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Model 6514 System Electrometer Instruction Manual

1. H n RINT Model 5156 Calibration Standard values RI 1 OUTPUT 14 CAL UNPR KI5156 Query 5156 standard values RI 1 ENTER 14 PUT 2 R100G R10G R1G R100M C1NF C100NF RINT 1 LOCAL 14 4 ia 1p Gl RINT 100 G ohm value R100G RINT 10 G ohm value R10G RINT 1 G ohm value RIG RINT 100 M ohm value R100M RINT 1 nF value CINF RINT 100 nF value C1lOONF D AvUyriuy ye GAO Ww oH Vie A O U w O O H 4 Calibration O ptions Remote calibration Calibration commands Table H 1 summarizes Model 6514 calibration commands Table H 1 Calibration commands Command Description CALibration PROTected CODE lt code gt CODE LOCK LOCK SENSe lt NRf gt DATA SAVE DATE lt NRf NRf NRf gt DATE NDUE lt NRf NRf NRf gt NDUE COUNt UNPRotected VOFFset IOFFset Eight character code password used to enable or unlock calibration Default KI0065 14 Calibration code query Lock out further calibration Return 1 if calibration is locked 0 otherwise Calibrate active function and range Query measurement cal constants Save all calibration data to non volatile memory Year Month Day when cal was last performed Query last cal date Year Month Day when 6514 is due for re cal Query cal due date
2. Figure 3 1 Insulator High impedance 6514 one of two voltage measurements HI oy i LO Vv rh ae RL1 5 lt RL2 c Leakage Path c COMMON M etal Mounting Plate GRD Disabled A Unguarded Insulator 6514 one of two On HI WI A GRD H j DUT i Tsg y EE Tig OV REL 4 common 2 M etal Mounting Plate GRD Enabled B Guarded Input cable leakage and capacitance In a similar manner to leakage in the test circuit leakage in the input cable could also corrupt high impedance measurements In the unguarded mode leakage in a triax cable occurs between the center conductor HI and the inner shield LO Inherently an input cable has capacitance that is formed by the center conductor HI inner shield LO and the insulator between them For high impedance measurements the RC time constant can significantly slow down measurement response To minimize the effects of cable leakage and input capacitance keep the input cable as short as possible and use guard With guard enabled the same potential is applied to both the center conductor and inner shield of the cable This eliminates leakage current and capacitor charging discharging NOTE Detailed information on Cable Leakage Resistance Input Capacitance Settling Time and Guarding Input Cables is provided in Volts and O
3. Model 6514 Pin 5 External Voltage Flyback Connection To other three 5 digital outputs External Power 5V Relay 4 aA 5V to 33V S Coil Digital O utput oa 9 T Flyback Diode 1ko Pull U p Resistor _ Pin 1 Digital Output 1 rA a Pin 9 Digital Ground Equivalent Circuit o Relay External Power Coil 3 4 a 5V to 33V Flyback O0 J Diode o lt Transistor Switch Digital I O Analog Outputs and External Feedback 11 5 Source mode logic control The digital outputs can be used as logic inputs to active TTL low power TTL or CMOS inputs For this mode of operation the output lines can source up to 2mA CAUTION Each output line can source up to 2mA Exceeding 2mA may cause damage to Model 6514 that is not covered by the warranty Figure 11 4 shows how to connect a logic device to one of the output lines When the output line is set HI the transistor will turn off transistor switch open to provide a reliable logic high output gt 3 75V When the output line is set LO the transistor turns on transistor switch closed to route current to digital ground As a result a low logic output OV is provided at the output If the second input B of the NAND gate is connected to another output line of the port the output of the NAND gate will go to logic 0 when both digital outputs are set HI Figure 11 4 Model 6514 NAND gate control 5V Logic 1kQ Dev
4. To allow many parallel connections to one instrument stack the connector Two screws are located on each connector to ensure that connections remain secure Current standards call for metric threads which are identified with dark colored screws Earlier versions had different screws which were silver colored Do not use these types of connectors on Model 6514 because it is designed for metric threads 12 6 Remote O peration Figure 12 2 shows a typical connecting scheme for a multi unit test system Figure 12 2 Instrument Instrument Instrument IEEE 488 connections oS ALLN Controller To avoid possible mechanical damage stack no more than three connectors on any one unit NOTE To minimize interference caused by electromagnetic radiation use only shielded IEEE 488 cables Available shielded cables from Keithley are Models 7007 1 and 7007 2 Remote O peration 12 7 To connect Model 6514 to the IEEE 488 bus follow these steps 1 Line up the cable connector with the connector located on the rear panel The connector is designed so that it will fit only one way Figure 12 3 shows the location of the TEEE 488 connector Figure 12 3 E PARTS SERVICE BY QUALIFIED PERSONNEL ONLY IEEE 488 connector location Misa IEEE 488 CHASSIS CHANGE IEEE ADDRESS WITH FRONT PANEL MENU RS232 AC AC A 2 Tighten the screws securely making sure not to over tighten them 3 Connect any additional connectors f
5. SCPI Reference Tables 17 9 Table 17 5 SOURce command summary Default Command Description parameter Ref SCPI SOURce2 Sec 10 TTL Program I O port LEVel lt NDN gt or lt NRf gt Specify 4 bit digital output pattern 15 LEVel Query output value CLEar Clear I O port return output to TTL pattern IMMediate Clear I O port immediately AUTO lt b gt Enable or disable auto clear OFF AUTO Query state of auto clear DELay lt n gt Specify delay pulse width for pass fail pattern 0 0001 0 to 60 sec DELay Query delay TTL4 Line 4 mode configuration MODE lt name gt Select output line 4 mode EOTest or BUSY EOT MODE Query line 4 mode BSTate lt ttl gt Select active TTL level for busy 1 HD or 0 LO 0 BSTate Query busy level lt NDN gt and lt NRf gt parameters lt NDN gt Bxxx Binary format each x 1 or 0 Hx Hexadecimal format x 0 to F Qx Octal format x 0 to 17 lt NRf gt Oto 15 Decimal format Table 17 6 STATus command summary Default Command Description parameter Ref SCPI STATus Note 1 Sec 13 v MEASurement Measurement event registers EVENt Read the event register Note 2 ENABle lt NDN gt or Program the enable register Note 3 lt NRf gt ENABle Read the enable register CONDition Read the condition register OPERation Operation event registers vV EVENt Read the event register Note 2 Vv 17 10 Table 17 6 c
6. OO0OO0O0000000 Ooo OOo oO DE ogo ogo O00 OO OC OO Calibrator Output r Model 6514 Electromete BN C to dual Banana Plug Adapter Connect Cable Shield to Output LO DC Voltage Calibrator 2 Turn on the power and allow a one hour warm up period Restore factory defaults and perform offset calibration as outlined above 3 Select the DC volts function on Model 6514 by pressing the V key and set the calibrator to output DC volts 4 Select Model 6514 2V range with the down RANGE key 5 Make sure zero check is enabled press ZCHECK then zero correct the instrument with ZCOR Disable zero check 6 Set the calibrator voltage to 0 0000V and turn on the output 7 Enable REL on Model 6514 Leave REL enabled for the remainder of the test Performance Verification 18 11 8 Verify voltage measurement accuracy for each of the voltages listed in Table 18 2 For each test point e Select the correct Model 6514 measurement range e Set the calibrator voltage to the indicated value e Verify that Model 6514 voltage reading is within the limits given in the table 9 Repeat the procedure for negative source voltages with the same magnitudes as those listed in Table 18 2 Table 18 2 Voltage measurement accuracy reading limits Mode 6514 volts reading limits 1 Year 18 C 28 C 2V 2 00000V 1 99946 to 2 00054V 20V 20 0000V 19 9947 to 20 0053V 200V 200
7. Recall 8 2 Recommended calibration equipment 19 3 Recommended test equipment 18 4 Register bit descriptions 13 11 Relative 7 1 7 2 Relative mX b and Percent 7 1 Remote calibration H 4 Remote calibration overview H 4 Remote Operation 12 1 Resetting the calibration code 19 19 Restoring factory defaults 18 9 Routine Maintenance 20 1 RS 232 connections 12 18 RS 232 interface reference 12 17 RS 232 settings 12 17 Safety symbols and terms 1 2 SCPI commands F 10 SCPI programming 1 15 2 3 2 18 3 7 4 8 5 5 8 4 9 9 10 12 SCPI programming digital output pattern 11 6 SCPI programming external feedback 11 17 SCPI programming filters 6 10 SCPI programming mX b and percent 7 6 SCPI programming range and digits 6 4 SCPI programming rate 6 7 SCPI programming relative 7 3 SCPI programming zero check and zero correct 2 15 SCPI Reference Tables 17 1 SCPI Signal Oriented Measurement Commands 15 1 Selecting and configuring an interface 12 2 Sending and receiving data 12 17 Serial polling and SRQ 13 9 Service request enable register 13 8 Setting and controlling relative 7 2 Setting digital output lines 11 5 Setting line voltage and replacing line fuse 20 2 Shielded fixture construction 11 12 Sink mode controlling external devices 11 3 Source mode logic control 11 5 Specifications A 1 Status and Error Messages 1 12 B 1 Status byte and service request SRQ 13 7
8. A Connections Input from n Prescaler vvv Pia Analog Output R Input Resistance of measuring device Fuse Model6514A B Equivalent Circuit Preamp out The preamp output of Model 6514 follows the signal amplitude applied to the input terminal The preamp output provides a guard output for volts measurements It can be used as an invert ing output or with external feedback in the amps and coulombs modes Connections and equiv alent circuits for the preamp output are shown in Figure 11 6 Full range outputs for the various functions and ranges are listed in Table 11 3 Digital I O Analog Outputs and External Feedback 11 9 Figure 11 6 Typical preamp out connections a Model 1683 Test Lead kit Model 6514 Rear Panel M easuring Device i e Chart recorder A Connections Vout Vin Vout linRe lt lt Preamp Out Preamp Out Common Common 0 12 lt Preamp Out Preamp Out Common Common 0 1Q Vout lout x RL Coulombs B Equivalent Circuit 11 10 Digital I O Analog O utputs and External Feedback Since the preamp output signal is not corrected during calibration gain error of up to 15 may appear at this output depending on function and range selection For all volts ranges preamp output accuracy is typically 1Oppm WARNING High voltage may be present between the preamp output and common ter minals depending on the input signa
9. The digital I O lines are available at the DB 9 connector on the rear panel of Model 6514 A custom cable using a standard female DB 9 connector is required for connection to Model 6514 Start of test The SOT start of test line of the Digital I O is used to control the start of the testing process When STest is the selected arm in event for the arm layer of the trigger model the testing pro cess will start when the SOT line is pulled low When test is the selected arm in event the test will start when the SOT line is pulled high Section 9 provides details on trigger model config uration NOTE Ifyou do not wish to use the SOT line to start the test you can use the immediate arm in event The testing process will start as soon as the LIMIT key is pressed assuming one or both limit tests are enabled The component handler will either maintain the SOT line high or low This is its not ready condition When the component handler is ready DUT properly position in the handler it will either pull the SOT line low or high to start the test Limit Tests 10 7 Digital output patterns Model 6514 uses digital output bit patterns to communicate test results to the component han dler For each limit test unique fail patterns are used for the HI and LO limits A pass pattern is used to indicate that there were no errors After a test is finished the appropriate output pattern is sent to the component handler The handler decodes
10. Bxxxx Binary format each x 1 or 0 Hx Hexadecimal format x 0 to F OQxx Octal format x 0 to 17 Note The lt NDN gt parameter type can be used to set the output pattern using non decimal values Convert the decimal value to its binary hexadecimal or octal equivalent and include the appropriate header B H or Q For example to set output lines 4 and 2 HI using the binary format send SOURce2 TTL B1010 More information about the lt NDN gt parameter type is provided in Section 13 see Programming Enable Registers Programming example The following command sequence sets output lines 4 and 2 HI and output lines 3 and 1 LO SOUR2 TTL 10 Set output lines 4 and 2 HI SOUR2 TTL Request output pattern value Analog outputs Digital 1 0 Analog Outputs and External Feedback 11 7 Model 6514 has two analog outputs on the rear panel The 2V ANALOG OUTPUT provides a scaled 2V output with a value of 2V corresponding to full range input The PREAMP OUT is especially useful in situations requiring buffering These two analog outputs are discussed in the following paragraphs WARNING CAUTION When floating input low above 30V RMS from earth ground hazardous voltage will be present at the analog outputs Hazardous voltage may also be present when the input voltage exceeds 30V RMS in the volts function or when input currents exceed 30pA in the amps function Connecting PREAMP OUT COMMON
11. Limit Limit LO HI Fail Pass Fail Limit Limit Limit 1 Test Wide Pass Band Limit 2 Test Narrow Pass Band Figure 10 2 shows an example where the HI and LO limits for limit 1 are 2V and the Hi and LO limits for limit 2 are 1 V A OV reading passes both limit 1 and limit 2 tests A 1 5V reading passes limit 1 but fails limit 2 A 2 5V reading fails both limit 1 and limit 2 Limit 1 Test Wide Pass Band Limit 2 Test Narrow Pass Band The 2 stage limit testing process is shown in Figure 10 3 If limit 1 fails the L1 message is displayed and the test is finished Limit 2 is not tested because the pass band relationship between the two stages implies that if limit 1 fails limit 2 must also fail If limit 1 passes the limit 2 test is performed If limit 2 fails the L2 message is displayed If both limit 1 and limit 2 pass the OK message is displayed The display messages for limit tests are summarized in Table 10 1 Limit Tests 10 3 A test is only performed if it is enabled Therefore you can perform a single stage test or a 2 stage test In the flowchart Figure 10 3 operation simply proceeds through a disabled test Figure 10 3 Operation model for limit test Measure DUT Display 1 Display o Yes Display OK Table 10 1 Test limit display messages Display Limit 1 Limit 2 Message Test Result Te
12. Set the calibrator current to 20 00000uA then adjust the display to agree with the cal ibrator current Allow 15 seconds for settling Press ENTER The unit will prompt for the negative full scale calibration point 20uA CAL Press ENTER Model 6514 will prompt for the negative full scale calibration current 20 00000 uA Set the calibrator output to 20 00000UA then adjust the display to agree with the cal ibrator value Allow 15 seconds for settling then press ENTER to complete calibration of the present range Press EXIT to return to normal display Repeat steps through 13 for the 200uA through 20mA ranges using Table 19 4 as a guide Figure 19 3 Connections for 20pA 2uA range calibration Calibration Table 19 4 20uA 20mA range amps calibration summary Mode 6514 range Calibrator currents Settling time 20uA OuA gt 15 sec 20 00000UA gt 15 sec 20 00000UA gt 15 sec 200UA OuA gt 15 sec 200 0000UA gt 15 sec 200 0000UA gt 15 sec 2mA OmA gt 15 sec 2 000000mA gt 15 sec 2 000000mA gt 15 sec 20mA OmA gt 15 sec 20 00000mA gt 15 sec 20 00000mA gt 15 sec Calibrate zero positive full scale and negative full scale for each range Triax cap used for zero cal points Allow calibration signal to settle for indicated time before calibrating each point 20pA 2pA range calibration 1 Connect the triax shielding cap to the Model 6514 INPUT ja
13. Using the zero check feature going from the enabled state to the disabled state causes a sud den change in the charge reading and is known as zero check hop This sudden change in charge also occurs when the auto discharge feature resets the charge reading to zero This hop in charge can be eliminated by taking a reading the instant zero check is disabled or when an auto dis charge occurs and subtracting it from all subsequent readings A better way to deal with this hop in charge is to enable Rel immediately after zero check is disabled or when auto discharge resets the charge reading This action nulls out the charge reading caused by the hop Application Capacitance measurements Figure 5 2 shows a general test circuit to measure a capacitor C Resistors R1 and R2 are used to limit current Select a value for R1 that will limit current to lt 100mA and select a value for R2 that will limit current to lt 20mA When switch S1 is closed the Keithley Model 230 voltage source charges the capacitor After waiting sufficient time for the capacitor to fully charge open switch S1 and close switch S2 to measure the charge The capacitance can now be calculated as follows C Q V where C is the capacitance in farads Q is the measured charge in coulombs V is the voltage used to charge the capacitor Figure 5 2 S1 S2 Measuring me T ra capacitors N RI R2 E c 230 V Source Co A e 6514 Range U nits Digits
14. screw is present connect it to safety earth ground using the wire recommended in the user documentation The A symbol on an instrument indicates that the user should refer to the operating instructions located in the manual The A symbol on an instrument shows that it can source or measure 1000 volts or more including the combined effect of normal and common mode voltages Use standard safety precautions to avoid personal contact with these voltages The Ai symbol indicates a connection terminal to the equipment frame The WARNING heading in a manual explains dangers that might result in personal injury or death Always read the associated information very carefully before performing the indicated procedure The CAUTION heading in a manual explains hazards that could damage the instrument Such damage may invalidate the warranty Instrumentation and accessories shall not be connected to humans Before performing any maintenance disconnect the line cord and all test cables To maintain protection from electric shock and fire replacement components in mains circuits including the power transformer test leads and input jacks must be purchased from Keithley Instruments Standard fuses with applicable national safety approvals may be used if the rating and type are the same Other components that are not safety related may be purchased from other suppliers as long as they are equivalent to the original component Note that selected parts sh
15. the handler to read the bit pattern and perform the binning operation This 10usec offset is used to make sure the correct bit pattern is read by the handler After the pass fail is read by the handler the digital output returns to the clear pattern 10 10 Limit Tests Front panel operation Limit test configuration Most aspects of limit testing are configured from the limit configuration menu When using a component handler the start of test STest Test or Immediate option is set from the arm layer configuration menu Once in a menu structure use the A and y keys to display menu items Use the cursor and p and the A and y keys to key in values To change polarity of a value place the cursor on or and press A and y To change range for the value place the cursor on the range symbol and use the a and y keys P pico y nano u micro m milli x1 K kilo M mega G giga T tera A menu item or value is selected by pressing ENTER Digital output bit patterns An output pattern is set by selecting a decimal value 0 to 15 that corresponds to the 4 bit BCD pattern of the output To determine the output pattern value add up the decimal weight values for the desired HI lines Output HI Line Out 4 Out 3 Out 2 Out 1 Decimal Weight 8 4 2 1 For example to set an output pattern to 0101 lines 3 and 1 HI set the output value to 5 4 1 Limits confi
16. tor to the Model 5156 TO 6517 DIGITAL I O connector using the optional Keithley CA 199 1A data transfer cable Also connect the Model 6514 to the GPIB or RS 232 port of the host com puter not shown Model 5156 Calibration Standard Model 6514 Electrometer Figure H 1 Data transfer connections CA 199 1A Cable Reading values To read out Model 5156 standard values send the following remote command to the Model 6514 CAL UNPR KI5 156 The unit will return an ASCII string of floating point values in the following order 100GQ 10GQ 1GQ 100M9 InF 100nF Note that the values will be delimited by commas Calibration Options H 3 Example program The program below demonstrates how to read back and display calibration standard values To use this program you will need the following e IBM PC compatible computer e Microsoft QBasic supplied with DOS 5 6 22 e CEC or Keithley IEEE 488 interface card installed in the computer e Installed CECHP EXE driver supplied with above interface card Program to read Model 5156 standard values via Model 6514 6514 primary address 14 PEN IEEE FOR OUTPUT AS 1 Open IEEE 488 output path PEN IEEE FOR INPUT AS 2 Open IEEE 488 input path RI 1 INTERM CRLF Set input terminator RI 1 OUTTERM LF Set output terminator RINT 1 REMOTE 14 Put 6514 in remote
17. 11 5ppm 19MQ 30ppm 100M2 120ppm Nominal resistance 2 100MQ 200ppm 1GQ 300ppm 10GQ 400ppm 100GQ 500ppm Nominal capacitance 2 InF 1 000ppm 100nF 1 000ppm Notes 1 90 day 23 5 C full range accuracy specifications shown 2 23 3 C accuracy of characterization 3 Connect red and black clips to make triax short Performance Verification 18 5 Table 18 1 cont Recommended verification equipment Description M anufacturer model Specifications Triax cable Keithley 7024 3 Low noise coax cable Keithley 4801 Triax to alligator clip cable3 Keithley 237 ALG 2 Triax to BNC adapter Keithley 7078 TRX BNC Triax shielding cap Keithley CAP 31 BNC to double banana plug adapter Pomona 1269 Notes 1 90 day 23 45 C full range accuracy specifications shown 2 23 3 C accuracy of characterization 3 Connect red and black clips to make triax short 18 6 Performance Verification The verification limits stated in this section have been calculated using only Model 6514 one year accuracy specifications and they do not include test equipment uncertainty If a particular measurement falls outside the allowable range recalculate new limits based on Model 6514 specifications and corresponding test equipment specifications Example reading limits calculation As an example of how verification limits are calculated assume you are testing the 20V range using a 20V input value Using M
18. 1GQ 10pF GQ Cin Input 10MQ Cr gt Ciy 10pF Coulombs Cp 1000pF 20nC 200nC O 1uF 2uC 20uC Zero correct Model 6514 has a zero correct feature to algebraically subtract the voltage offset term from the measurement Perform the following steps to zero correct the volts or amps function NOTE The ZCOR key toggles zero correct on and off If zero correct is enabled ZZ or CZ message displayed press ZCOR to disable it pO Aer ae Select the volts V or amps I function Enable zero check ZC message displayed Select the range that will be used for the measurement or select the lowest range Press ZCOR to enable zero correct ZZ message displayed Press ZCHK to disable zero check Readings can now be taken from the display The CZ message indicates that the dis played reading is zero corrected M easurement Concepts 2 15 NOTES Zero check will enable whenever the ohms function is selected Model 6514 will remain zeroed even if it is upranged If downranged re zero the instrument Model 6514 does not have to be re zeroed as long as the ambient temperature remains stable Zero correction cancels the voltage offset term of the amplifier With both zero check and zero correct enabled the instrument may not display a perfectly zeroed reading If Model 6514 is operating at or near Tc z zero correction will have very little affect Tcarz is the internal tempera
19. 3F 63 2 LAG Stays low 2E 46 3 Data Set high 2A 42 4 Data Stays high R 52 82 5 Data Stays high S 53 83 6 Data Stays high T 54 84 Assumes primary address 14 F 12 EEE 488 Bus Overview IEEE command groups Command groups supported by the Model 6514 are listed in Table F 5 Common commands and SCPI commands are not included in this list Table F 5 IEEE command groups HANDSHAKE COMMAND GROUP NDAC NOT DATA ACCEPTED NRFD NOT READY FOR DATA DAV DATA VALID UNIVERSAL COMMAND GROUP ATN ATTENTION DCL DEVICE CLEAR IFC INTERFACE CLEAR REN REMOTE ENABLE SPD SERIAL POLL DISABLE SPE SERIAL POLL ENABLE ADDRESS COMMAND GROUP LISTEN LAG LISTEN ADDRESS GROUP MLA MY LISTEN ADDRESS UNL UNLISTEN TALK TAG TALK ADDRESS GROUP MTA MY TALK ADDRESS UNT UNTALK OTA OTHER TALK ADDRESS ADDRESSED COMMAND GROUP ACG ADDRESSED COMMAND GROUP GTL GO TO LOCAL SDC SELECTIVE DEVICE CLEAR STATUS COMMAND GROUP RQS REQUEST SERVICE SRQ SERIAL POLL REQUEST STB STATUS BYTE EOI END EEE 488 Bus Overview F 13 Interface function codes The interface function codes which are part of the IEEE 488 standards define an instru ment s ability to support various interface functions and should not be confused with pro gramming commands found elsewhere in this manual The interface function codes for the Model 6514 are listed in Table F 6
20. VOLTage DC VOLT Secs 3 Vv CURRent DC RESistance or CHARge 4 5 FUNCtion Query measurement function V DATA Path to return instrument readings Secs 3 vV 4 5 LATest Return the last instrument reading v VOLTage DC Path to configure volts function vV NPLCycles lt NRf gt Set integration rate in line cycles PLC 0 01 to 6 60Hz Sec 6 vV 10 5 50Hz NPLCycles Query NPLC vV RANGe Configure measurement range Sec 6 vV UPPer lt NRf gt Select range 210 to 210 volts 21 v UPPer Query range value vV AUTO lt b gt Enable or disable autorange see Note vV ULIMit lt NRf gt Select autorange upper limit 210 to 210 210 volts ULIMit Query upper limit for autorange LLIMit lt NRf gt Select autorange lower limit 210 to 210 2 1 volts LLIMit Query lower limit for autorange AUTO Query state of autorange vV GUARd lt b gt Enable or disable driven guard OFF Sec 3 GUARd Query state of driven guard XFEedback lt b gt Enable or disable external feedback OFF Sec 11 XFEedback Query state of external feedback CURRent DC Path to configure amps function vV NPLCycles lt NRf gt Set integration rate in line cycles PLC 0 01 to 6 60Hz Sec 6 vV 10 5 50Hz NPLCycles Query NPLC vV RANGe Configure measurement range Sec 6 vV UPPer lt NRf gt Select range 0 021 to 0 021 amps 2 le 4 v UPPer Query range value vV AUTO lt b gt Enable
21. WARNING Themaximum common mode voltage voltage between analog common and chassis ground is 500V peak DC to 60Hz sine wave Exceeding this value may cause a breakdown in insulation creating a shock hazard CAUTION Themaximum input voltage is 250V peak DC to 60Hz sine wave E xceed ing this voltage may result in instrument damage Performance Verification 18 9 Restoring factory defaults Before performing each verification procedure restore the instrument to its factory front panel defaults as follows 1 Press SHIFT then SETUP The instrument will display the following prompt RESTORE FACT 2 Using either RANGE key select FACT then restore the factory default conditions by pressing ENTER NOTE You can use either RANGE key to select among FACT GPIB and USR setups Be sure to use FACT defaults for the verification procedures Input bias current and offset voltage calibration Before performing the performance verification procedures perform input bias current and offset voltage calibration as outlined below Note that these offsets will be lost if power is cycled unless you save them first O ffset voltage calibration 1 From the calibration menu use the down RANGE key to display the following CAL VOFFSET 2 Press ENTER The instrument will prompt for a short INPUT SHORT 3 Connect the triax short triax cable with red and alligator black clips connected together to the rear panel INPUT jack 4 Pre
22. a KEITHLEY MAQ5 IN IEEE 488 CHANGE IEEE ADDRESS 250V PK OUTPUT WITH FRONT PANEL MENU omeo omo O O INPUT 250V PK DIGITAL I O TRIGGER LINK RS232 LINE RATING INPUT e A S 6 onz PREAMP CHASSIS ESAN OUT ine OFF ON 2V ANALOG 630mAT 100 VAC SuIGWS ouput a 120 VAC FIR Fi H V GUARD INPUT PROGRAMMABLE 315mAT 220 VAC Vv INTERNAL SB 240 VAC GAUTION For CONTINUED PROTECTION AGAINST FIRE HAZARD REPLACE FUSE WITH SAME TYPE AND RATING 6514 Rear Panel GRD Enabled Step 6 Disable zero check and take a reading from the display V D rop and I Source for ohms Model 6514 performs ohms measurement by sourcing a known test current through the DUT and then measuring the voltage drop across it The resistance reading is then calculated R V I and displayed Volts and O hms Measurements 3 7 While the electrometer is measuring ohms the test current through the DUT and the voltage drop across it can be displayed as follows V Drop While displaying an ohms reading press SHIFT and then Q to display the voltage drop across the DUT The VQ message will indicate that a V Drop reading is being displayed To return to the normal ohms reading again press SHIFT and then Q Test current While displaying an ohms or V Drop reading press the Q key The test cur rent ISRC will be displayed for as long as you hold the key down WARNING Theohms function
23. amps function Commands Description Default Ref SENSe SENSe Subystem FUNCtion CURrent Select Amps function VOLT A DATA Return latest raw reading B CURRent DAMPing lt b gt Enable or disable damping OFF INITiate Trigger one or more readings B READ Trigger and return reading s B A SENSe FUNCtion lt name gt Parameters CURRent Amps function VOLTage Volts function RESistance Ohms function CHARge Coulombs function Note that the parameter names are enclosed in single quotes However double quotes can instead be used Each measurement function remembers its own unique range setting B SENSe D ATA This command does not trigger a reading It simply returns the last raw reading string It will not return the result of any instrument calculation The reading reflects what is applied to the input To return a fresh new reading you can send the INITiate command to trigger one or more readings before sending DATA Details on INITiate are provided in Section 9 While Model 6514 is busy performing measurements the DATA command will not return the reading string until the instrument finishes and goes into the idle state Amps M easurements 4 9 NOTES The format that the reading string is returned in is set by commands in the FORMat Subsystem see Section 16 If there is no reading available when DATA is sent an error 230 will occur
24. then press ENTER Model 6514 will prompt for the negative full scale calibration point 20PA CAL Press ENTER The instrument will prompt for the negative full scale current 20 00000 PA Set the calibrator output voltage to 2 000000V then calculate the calibration current from the calibrator voltage and standard resistor value I V R Adjust Model 6514 dis play to agree with the calculated current Allow the settling time listed in Table 19 5 then press ENTER to complete calibration of the present range Press EXIT to return to normal display Repeat steps through 13 for the 200pA through 2uA ranges using Table 19 5 as a guide Be sure to make connections to the correct standard resistor Calibration 19 13 Table 19 5 20pA 2uA range amps calibration summary Model 6514 range Calibrator voltages Standard resistor C alibration currents Settling time 20pA 100GQ OpA gt 2 min 2 000000V 100GQ 20pA gt 2 min 2 000000V 100GQ 20pA gt 2 min 200pA 10GQ OpA gt 2 min 2 000000V 10GQ 200pA gt 2 min 2 000000V 10GQ 200pA gt 2 min 2nA 1GQ OnA gt 15 sec 2 000000V 1GQ 2nA gt 15 sec 2 000000V 1GQ 2nA gt 15 sec 20nA 1GQ OnA gt 15 sec 20 00000V 1GQ 20nA gt 15 sec 20 00000V 1GQ 20nA gt 15 sec 200nA 100MQ OnA gt 15 sec 20 00000V 100MQ 200nA gt 15 sec 20 00000V 100MQ 200nA gt 15 sec 2uA 100MQ OuA gt 15 sec 200 0000V 100MQ 2uA gt 15 sec 20
25. u oE U vI N oE lt vI Su os vr o Tt tlt ud 6z ET W 6z ET a s9 YD ET ae 8 i E 8z ZI q 8z gt ZI Sd dd ZI o o ti t x LZ IL zJ LZ IL Osa IN IL T t o t z f 9z Z OT f 9z OT ans n OT o Tt o T A SZ A 6 Gz 6 6 dS Wa LOL LH 6 T o o t x y vz x 8 H vz 8 8 adS NYO 9 sg 8 o o o T M 6 EZ M L 5 EZ L L ga Bg L T ti tijo A 4 zz A 9 d zZz 9 9 x NAS OV 9 o Tt tifo n IZ n S a IZ S S xNdd AVN Odd ONS S T o t o 3 p oz Ll v a oz v v wa vod Sds LOA v o o tT O0O s 2 61 S D 6T A xa T t ojo J q ST Y z g ST z z ae zoa XIS z o T o o0o b e LI 0 T v LI T T i on t9q 19 HOS T T o o o d 9T d o 9T o o dS ma INN o oloj oj o mou 1 f t t zi Mz 9 W9 s Ms ri Wr e WE az MZ a T WTI o wo lt taunfod a a a fa sa O T o 7 T A 7 o a 7 T a 7 o o T O o ra T IT 3 z o a z o g z Tl o 3 T 3 o 3 o sa T t s t s t lt o lt o S o 3 o a x x x x x x x 2 x a Figure F 3 Command codes EEE 488 Bus Overview F 9 Addressed multiline commands Addressed commands are multiline commands that must be preceded by the device listen address before that instrument will respond to the command in question Note that only the addressed device will respond to these commands Both the commands and the address preced ing it are sent with ATN true SDC Selective Device Clear T
26. 178 Expression data not allowed EE 171 Invalid expression EE 170 Expression error EE 168 Block data not allowed EE 161 Invalid block data EE 160 Block data error EE Table B 1 cont Status and error messages Status and Error Messages Number Description Event 158 String data not allowed EE 154 String too long EE 151 Invalid string data EE 150 String data error EE 148 Character data not allowed EE 144 Character data too long EE 141 Invalid character data EE 140 Character data error EE 128 Numeric data not allowed EE 124 Too many digits EE 123 Exponent too large EE 121 Invalid character in number EE 120 Numeric data error EE 114 Header suffix out of range EE 113 Undefined header EE 112 Program mnemonic too long EE 111 Header separator error EE 110 Command header error EE 109 Missing parameter EE 108 Parameter not allowed EE 105 GET not allowed EE 104 Data type error EE 103 Invalid separator EE 102 Syntax error EE 101 Invalid character EE 100 Command error EE 000 No error SE Measurement events 101 Low limit 1 failed SE 102 High limit 1 failed SE 103 Low limit 2 failed SE 104 High limit 2 failed SE 105 Active limit tests passed SE 106 Reading available SE B 3 B 4 Status and Error M essages Table B 1 cont Status and error messages Number Description Event 107 Reading overflow SE 108 Buffer available SE 109 Buffer fu
27. B6 when error occurs The first command of the following sequence enables EAV error available When an invalid command is sent line 4 bits B2 EAV and B6 MSS of the status byte register set to 1 The last command reads the status byte register using the binary format which directly indicates which bits are set The command to select format FORMat SREGister is documented in Table 13 2 To determine the exact nature of the error you will have to read the error queue see Queues CLS Clear Error Queue SRE 4 Enable EAV FORM SREG BIN Select binary format BadCommand Generate error STB Read Status Byte Register NOTE An example program to demonstrate serial polling Generating SRQ on buffer full is provided in Appendix E Status Structure 13 11 Status register sets As shown in Figure 13 1 there are four status register sets in the status structure of Model 6514 standard event status operation event status measurement event status and questionable event status Register bit descriptions Standard event status The used bits of the standard event register shown in Figure 13 4 are described as follows Bit BO operation complete Set bit indicates that all pending selected device opera tions are completed and Model 6514 is ready to accept new commands This bit only sets in response to the OPC query command See Section 14 for details on OPC and OPC B
28. Cursor left arrow key STORE key RECALL key DELAY key DAMP key HALT key TRIG key EXIT key 16 10 DISPlay FORMat and SYSTem This command is used to simulate front panel key presses For example to select the volts measurement function send the following command to simulate pressing the V key SYSTem KEY 2 The key press codes are also shown in Figure 16 3 The queue for the KEY query command can only hold one key press When KEY is sent and Model 6514 is addressed to talk the key press code number for the last key pressed either physically or with KEY is sent to the computer Figure 16 3 1 2 3 4 5 6 7 8 16 11 Key press codes CONF ARM_CONF TRIG HALT TRIG 17 SCPI Reference Tables Table 17 1 CALCulate command summary Table 17 2 DISPlay command summary Table 17 3 FORMat command summary Table 17 4 SENSe command summary Table 17 5 SOURce command summary Table 17 6 STATus command summary Table 17 7 SYSTem command summary Table 17 8 TRACe command summary Table 17 9 TRIGger command summary 17 2 SCPI Reference Tables General notes Brackets are used to denote optional character sets These optional characters do not have to be included in the program message Do not use brackets in the program message Angle brackets lt gt are used to indicate parameter type Do not use angle brackets in the program message The Boo
29. Power up and CLS clears all bits STATus PRESet has no effect Enable registers Power up and STATus PRESet clears all bits CLS has no effect Error queue Power up and CLS empties the error queue STATus PRESet has no effect Error queue messages Power up enables error messages and disables status messages CLS and STATus PRESet have no effect SCPI Reference Tables 17 11 Table 17 7 SYSTem command summary Default Command Description parameter Ref SCPI SYSTem Sec 16 ZCHeck lt b gt Enable or disable zero check ON Sec 2 ZCHeck Query state of zero check ZCORrect Zero correct Sec 2 STATe lt b gt Enable or disable zero correct OFF STATe Query state of zero correct ACQuire Acquire a new zero correct value PRESet Return to SYSTem PRESet defaults Vv LFRequency lt freq gt Select power line frequency 50 or 60 Hz Sec 1 LFRequency AZERo Path to control autozero Sec 2 Vv STATe lt b gt Enable or disable autozero ON Vv STATe Query state of autozero Vv TIME Timestamp RESet Reset timestamp to 0 seconds POSetup lt name gt Select power on setup RST PRESet or SAVx where x 0 to 4 POSetup Query power on setup VERSion Query SCPI revision level vV ERRor Read error queue see Note Sec 13 v NEXT Read and clear oldest error status code and message ALL Read and clear all errors status code and message COUNt Read the number of messa
30. Read operation condition register MEASurement CONDition Read measurement condition register QUEStionable CONDition Read questionable condition register Event registers As Figure 13 1 shows each status register set has an event register When an event occurs the appropriate event register bit sets to 1 The bit remains latched to 1 until the register is reset Reading an event register clears the bits of that register CLS resets all four event registers The commands to read the event registers are listed in Table 13 5 For details on reading reg isters see Reading registers Table 13 5 Common and SCPI commands event registers Command Description ESR Read standard event status register STATus STATus subsystem OPERation EVENt Read operation event register MEASurement EVENt Read measurement event register QUEStionable EVENt Read questionable event register Note Power up and CLS resets all bits of all event registers to 0 STATus PRESet has no effect Event enable registers Status Structure 13 17 As Figure 13 1 shows each status register set has an enable register Each event register bit is logically ANDed amp to a corresponding enable bit of an enable register Therefore when an event bit is set and the corresponding enable bit is set as programmed by the user the output summary of the register will set to 1 which in turn sets the summary bit
31. See Programming Syntax in Section 12 None See Display Subsystem in Section 16 See Common Commands in Section 14 Section 19 Not applicable IEEE 488 and SCPI Conformance Information G 3 Table G 1 cont IEEE 488 documentation requirements Requirements Description or reference 15 Macro information Not applicable 16 Response to IDN identification See Common Commands in Section 14 17 Storage area for PUD and PUD Not applicable 18 Resource description for RDT and RDT Not applicable 19 Effects of RST RCL and SAV See Common Commands in Section 14 20 TST information See Common Commands in Section 14 21 Status register structure See Status Structure in Section 13 22 Sequential or overlapped commands All are sequential except INIT which is overlapped 23 Operation complete messages OPC OPC and WAI see Common Commands in Section 14 G 4 IEEE 488 and SCPI Conformance Information Table G 2 Coupled commands Sending Changes To CALC1 FORM KMAT PERC ACQ CALC2 NULL ACQ VOLT RANG UPP lt n gt CURR RANG UPP lt n gt RES RANG UPP lt n gt CHAR RANG UPP lt n gt VOLT NPLC lt n gt CURR NPLC lt n gt RES NPLC lt n gt CHAR NPLC lt n gt TRAC POIN lt n gt TRAC CLE CHAR RANG AUTO LGR lt n gt CHAR RANG AUTO ON CALC1 FORM KMAT PERC REF lt n gt CALC2 NULL OFFS lt n gt VO
32. Set trigger delay 0 to 999 9998 sec 0 0 AUTO lt b gt Enable or disable auto delay OFF TCONfigure DIRection lt name gt Enable SOURce or disable ACCeptor bypass ACC D AS YNchronous Configure input output triggers ILINe lt NRf gt Select input trigger line 1 2 3 4 5 or 6 1 E OLINe lt NRf gt Select output trigger line 1 2 3 4 5 or 6 2 E OUTPut lt name gt Output trigger after measurement SENSe or NONE not at all NONE TRIGger CLEar Clear pending input trigger NONE F 9 10 Triggering A ABORt If operation has been started by the INITiate command ABORt will cancel all operations and immediately return to the instrument to the idle state If operation has been started by READ or MEASure ABORt has no affect B INITiate 1 After sending this command to take the instrument out of idle the instrument will per form one or more measurements and then return to idle The FETch command can then be used to read the last reading that was measured 2 If INITiate is sent while the instrument is operating within the trigger model it will not execute until the operation returns to the idle state 3 One alternative to using INITiate is to use the READ command When READ is sent the instrument is taken out of idle and all readings that are taken are returned see Section 15 for details on READ C ARM SOURce lt name gt With the TIMer control source selected use the ARM TI
33. Trigger one reading Acquire zero correct value Disable zero check Perform zero correction The INITiate command in the above sequence is used to trigger a reading This reading is the offset that is acquired as the zero correct value See Section 9 for more information on INITiate NOTE Sending the ACQuire command while zero check is disabled will result in an error The command will not be executed M easurement Concepts 2 17 Input bias current and offset voltage calibration The input bias current and offset voltage calibration procedures that follow should be per formed periodically to actively cancel input bias current and offset voltage optimizing measure ment accuracy particularly at low levels Front panel Front panel input bias current calibration 1 Access the front panel calibration menu by pressing SHIFT then CAL NOTE See Section 19 for details on other calibration menu selections 2 From the calibration menu use the down RANGE key to display the following CAL IOFFSET 3 Press ENTER The instrument will prompt for the triax shielding cap as follows INPUT CAP 4 Connect a triax shielding cap to the rear panel INPUT jack Use a Keithley CAP 31 or equivalent Press ENTER to complete input bias current calibration 6 If you wish to perform front panel offset voltage calibration proceed to Step 2 of the pro cedure below Otherwise press EXIT to return to normal display de Front panel off
34. and the 20 model is 20 ft 6m in length CS 751 barrel adapter This is a barrel adapter that allows you to connect two triax cables together Both ends of the adapter are terminated with 3 lug female triax connectors GPIB and trigger link cables and adapters Models 7007 1 and 7007 2 shielded GPIB cables Connect Model 6514 to the GPIB bus using shielded cables and connectors to reduce electromagnetic interference EMI Model 7007 1 is Im long Model 7007 2 is 2m long M odels 8501 1 and 8501 2 trigger link cables Connect Model 6514 to other instruments with Trigger Link connectors e g Model 7001 Switch System Model 8501 1 is Im long Model 8501 2 is 2m long M odel 8502 trigger link adapter Lets you connect any of the six trigger link lines of Model 6514 to instruments that use the standard BNC trigger connectors M odel 8503 DIN to BNC trigger cable Lets you connect trigger link lines one Voltmeter Complete and two External Trigger of Model 6514 to instruments that use BNC trigger con nectors Model 8503 is Im long 1 4 Getting Started Rack mount kits Model 4288 1 single fixed rack mount kit Mounts a single Model 6514 in a standard 19 inch rack Model 4288 2 side by side rack mount kit Mounts two instruments Models 182 428 486 487 2000 2001 2002 2010 2400 2410 2420 2430 6430 6514 6517 A 7001 side by side in a standard 19 inch rack M odel 4288 4 side by side rack mount
35. and the result of the calculation will be displayed Note that the calculation will be applied to all measurement functions 8 To disable mX b again press SHIFT and then MX B The MATH annunciator will turn off Percent This math function determines percent deviation from a specified reference value The per cent calculation is performed as follows Input Reference x109 Percent where Input is the normal display reading Reference is the user entered constant Percent is the displayed result To configure and control the percent calculation perform the following steps 1 Press SHIFT and then to display the present reference value REF 1 000000 factory default 2 Key in a reference value The lt and p keys control cursor position and the A and w range keys increment and decrement the digit value To change range place the cursor on the range symbol and use the a and y keys With the cursor on the polarity sign the A and y keys toggle polarity 3 Press ENTER The MATH annunciator will turn on and the result of the calculation will be displayed Note that the calculation will be applied to all measurement functions 4 To disable percent again press SHIFT and then The MATH annunciator will turn off NOTES The result of the percent calculation is positive when the input exceeds the reference and negative when the input is less than the reference The result of the percent calculation may be displayed in expo
36. assume the following readings 20V 1V 3V The readings are re arranged in an ascending order as follows 1V 3V 20V From the above readings it is apparent that 3V is the median middle most reading The number of sample readings used for the median calculation is determined by the selected rank 1 to 5 as follows Sample readings 2x R 1 where R is the selected rank 1 to 5 For example a rank of 5 will use the last 11 readings to determine the median 2 x 5 1 11 Each new reading replaces the oldest reading and the median is then determined from the updated sample of readings Median filter operation The median filter operates as a moving type filter For example if the median filter is configured to sample 11 readings Rank 5 the first filtered reading will be calculated and displayed after 11 readings are acquired and placed in its filter stack Each sub sequent reading will then be added to the stack oldest reading discarded and another median filter reading will be calculated and displayed The median filter operation will reset start over whenever the Zero Check operation is performed or the function is changed Median filter configuration control The MEDN key is a toggle action key It will either disable the median filter displays MEDIAN OFP or access the configuration menu to enable the median filter 1 Press the MEDN key to display the present filter rank 2 Use the RANGE 4 or y ke
37. command This programming example demonstrates a simple method for taking and displaying on the computer CRT a specified number of readings The product of the arm count and trigger count determines the number of readings to take The RST default for both counters is one Therefore READ will trigger and return one reading 1 x 1 1 If for example you want to take 10 read ings you can set one of the counters to 10 while keeping the other counter set to one READ will trigger and return 10 readings 10 x 1 10 The following program takes 10 readings on the Volts function and displays them on the com puter CRT For QuickBASIC 4 5 and CEC PC488 interface card edit the following line to where the QuickBASIC libraries are on your computer SINCLUDE c qb45 ieeeqb bi Initialize the CEC interface as address 21 CALL initialize 21 0 Reset controls clear buffer and place 2182 in idle CALL SEND 14 rst status CALL SEND 14 trac cle status CALL SEND 14 trig coun 10 status CALL SEND 14 form elem read status CALL SEND 14 read status reading SPACES 300 CALL ENTER reading length 14 status PRINT reading Example Programs E 7 Controlling the Model 6514 via the RS 232 CO M2 port This example program illustrates the use of the Keithley Model 6514 interfaced to the RS 232 COM2 port The Model 6514 is set up to tak
38. 10 2 Limit tests example oo eee cece ceeceseeeeeeseeeeeeeeeeeeeseeeeeens 10 2 Figure 10 3 Operation model for limit test eee ceeeeseeeeeeeeeceeeteeeeeees 10 3 Figure 10 4 Binning systemi sisiicesciscissecsciaciuseveststaccugssteedeeoss Ean 10 4 Figure 10 5 Operation model for limit testing with binning 0 0 10 5 Figure 10 6 Handler interface connections eeeeeeeeeeseeeeeceeceseteeeeeeee 10 6 Figure 10 7 Digital output auto clear timing example eee 10 9 11 Digital 1 0 Analog O utputs and External Feedback Figure 11 1 Digital VO port senretene igen eee AE 11 2 Figure 11 2 Digital I O port simplified schematic eee eeeeeteeeeeeees 11 3 Figure 11 3 Controlling externally powered relays eee ee eeeeeeeeee 11 4 Figure 11 4 NAND Bate Control 5 cssccsscsscsenssescngscecsecaseovscsnsssdeeatesdosensesots 11 5 Figure 11 5 Typical 2V analog output Connections eee eeeeeeeee 11 8 Figure 11 6 Typical preamp out CONNECTIONS 00 0 eee ee eeeeee eee eeeeeeeeee 11 9 Figure 11 7 Electrometer input circuitry external feedback mode 11 12 Figure 11 8 Shielded fixture construction oe eee eeeeee teense teeeeeees 11 14 Figure 11 9 Transdiode logarithmic current configuration 11 15 Figure 11 10 Non decade current gains 0 0 eee eeeeeecseeeee cee eeseeeeneees 11 16 12 Figure 12 1 Figure 12 2 Figure 12 3 Figure 12 4 13 Figure 13 1 Figure 13 2 Figure 13 3 Figure 13 4 Fi
39. 5 For these mea surements circuit high is connected to the center conductor of the input connector while circuit low is connected to the COMMON banana jack terminal With guard GRD on the driven guard is available at the inner shell of the triax connector which is connected to the metal guard plate WARNING The guard voltage is at the same potential as the input Therefore hazard ous voltage on the input will also be present on the guard plate To prevent electric shock always use a metal safety shield as shown in Figure 2 5 for guarded voltage measurements above 30V rms 42V peak The metal safety shield must be connected to safety earth ground using 18 AWG or larger wire WARNING With an open input up to 250V peak may be present on the guard terminals while in Volts or Ohms To prevent this enable zero check whenever the input is open The driven guard is used to eliminate leakage current and capacitance in high impedance cir cuits which could corrupt the volts or ohms measurement The concept of guarding techniques are covered in Section 3 Figure 2 5 HI Basic connections for guarded Measure Volts measurements Chassis Ground TT TE Metal Guard Plate GRD y INPUT 250V PK eS a Safety Earth O LO Ground COMMON H M easure O hms Chassis Ground M etal Guard Plate M etal Safety Shield INPUT 250V PK I 4 e Safety O LO FZ E
40. 5733 7556 www keithley jp Korea Seoul 82 2 574 7778 Fax 82 2 574 7838 wwwkeithley com Netherlands Gorinchem 0183 635333 Fax 0183 630821 www keithley nl Singapore Singapore 65 6747 9077 Fax 65 6747 2991 www keithley com Sweden Solna 08 509 04 600 Fax 08 655 26 10 www keithley com Taiwan Hsinchu 886 3 572 9077 Fax 886 3 572 9031 www keithley com tw 3 04 M odel 6514 System Electrometer Instruction M anual 1998 Keithley Instruments Inc All rights reserved Cleveland Ohio U S A Fourth Printing May 2003 Document Number 6514 901 01 Rev D Manual Print History The print history shown below lists the printing dates of all Revisions and Addenda created for this manual The Revision Level letter increases alphabetically as the manual undergoes subsequent updates Addenda which are released between Revisions contain important change information that the user should incorporate immediately into the manual Addenda are numbered sequentially When a new Revision is created all Addenda associated with the previous Revision of the manual are incorporated into the new Revision of the manual Each new Revision includes a revised copy of this print history page Revision A Document Number 6514 901 01 ccecccccccsccssccssecessccssecesseesseeesseesseees Addendum A Document Number 6514 901 02 ceceseseseeeseeseeeeeeeeeseeeeeeeaeeeee Revision B Document Number 6514 901 01 Revisio
41. 6565 www keithley com France Saint Aubin 01 64 53 20 20 Fax 01 60 11 77 26 wwwkeithley fr Germany Germering 089 84 93 07 40 Fax 089 84 93 07 34 wwwkeithley de Great Britain Theale 0118 929 7500 Fax 0118 929 7519 e wwwkeithley co uk India Bangalore 91 80 2212 8027 Fax 91 80 2212 8005 wwwkeithley com Italy Milano 02 48 39 16 01 Fax 02 48 39 16 28 wwwkeithley it Japan Tokyo 81 3 5733 7555 Fax 81 3 5733 7556 www keithley jp Korea Seoul 82 2 574 7778 Fax 82 2 574 7838 wwwkeithley com Netherlands Gorinchem 0183 635333 Fax 0183 630821 wwwkeithley nl Singapore Singapore 65 6747 9077 Fax 65 6747 2991 wwwkeithley com Sweden Solna 08 509 04 600 Fax 08 655 26 10 wwwkeithley com Taiwan Hsinchu 886 3 572 9077 Fax 886 3 572 9031 wwweithley com tw Copyright 2004 Keithley Instruments Inc Printed in U S A 3 04
42. ARM SOURce PSTest Event detection for the arm layer is satisfied when a positive going pulse via the SOT line of the Digital I O is received from a component handle see Limit Testing in Section 10 BSTest ARM SOURce BSTest Event detection for the arm layer is satisfied when either a positive going or a negative going pulse via the SOT line of the Digital I O is received from a component handler see Limit Testing in Section 10 Trigger In source The Trigger In control sources are explained as follow Immediate TRIGger SOURce IMMediate Event detection for the trigger layer is satisfied immediately allowing operation to continue on to perform a measurement T Link TRIGger SOURce TLINk Event detection for the trigger layer is satisfied when an input trigger via the TRIGGER LINK connector is received by Model 6514 Note that if the source bypass is set to ONCE TRIGger DIRection SOURce operation will loop around the source detector on the initial pass through the arm layer Detection for each subsequent pass is satisfied by an input trigger The bypass resets when Model 6514 leaves the trigger layer Trigger delay A programmable delay is available after event detection It can be set manually 0 to 999 9998 seconds or an auto delay can be used With auto delay selected the Model 6514 automatically sets delay according to function and range The auto delay settings are listed in Table 9 1 9 6 Trigge
43. BINary Binary format A FEED lt name gt Name parameters CALCulate1 Limit tests will be performed on the result of a math calculation mX b or percent SENSe Limit tests will be performed on the input signal Note however that Rel can be used on the result of a math calculation as well as the input signal Limit tests will be performed on the result of the Rel operation see CALCulate2 NULL Details on rela tive mX b and percent are provided in Section 7 B lt NDN gt and lt NRf gt parameters lt NDN gt Bxxxx Binary format each x 1 or 0 Hx Hexadecimal format x 0 to F Qxx Octal format x 0 to 17 lt NRf gt Oto 15 Decimal format An output pattern is set by sending a parameter value that corresponds to the 4 bit BCD pat tern of the output The parameter value can be sent in the binary decimal hexadecimal or octal format For example if you wish to set lines 4 2 and 1 HI the binary parameter value would 10 14 Limit Tests be 1011 To use one of the other formats convert the binary number to its decimal hexadecimal or octal equivalent Binary 1011 Decimal 11 Hexadecimal B Octal 13 The lt NDN gt non decimal numeric parameter type is used to send non decimal values These values require a header B H or Q to identify the data format being sent The letter in the header can be upper or lower case The lt NRf gt numeric representation format paramet
44. C TEEE 488 BUS IMPLEMENTATION MULTILINE COMMANDS DCL LLO SDC GET GTL UNT UNL SPE SPD IMPLEMENTATION SCPI IEEE 488 2 SCPI 1996 0 DDC IEEE 488 1 UNILINE COMMANDS IFC REN EOI SRQ ATN INTERFACE FUNCTIONS SH1 AH1 T5 TEO L4 LEO SR1 RL1 PPO DC1 DT1 Co E1 PROGRAMMABLE PARAMETERS Function Range Zero Check Zero Correct EOI DDC mode only Trigger Terminator DDC mode only Data Storage 2500 Storage Calibration SCPI mode only Display Format SRQ REL Output Format Guard V offset Cal I offset Cal ADDRESS MODES TALK ONLY and ADDRESSABLE LANGUAGE EMULATION 6512 617 617HIQ emulation via DDC mode TRIGGER TO READING DONE 150ms typical with external trigger RS 232 IMPLEMENTATION Supports SCPI 1996 0 Baud Rates 300 600 1200 2400 4800 9600 19 2k 38 4k 57 6k Protocols Xon Xoff 7 or 8 bit ASCII parity odd even none Connector DB 9 TXD RXD GND A 3 A 4 Specifications GENERAL DISPLAY 6 2 digit vacuum fluorescent OVERRANGE INDICATION Display reads OVRFLOW RANGING Automatic or manual CONVERSION TIME Selectable 0 01 PLC to 10 PLC PROGRAMS Provide front panel access to IEEE address choice of engineering units or scientific notation and digital calibration MAXIMUM INPUT 250V peak DC to 60Hz sine wave 10s per minute maximum on mA ranges MAXIMUM COMMON MODE VOLTAGE DC to 60Hz sine wave Electrometer 500V peak ISOLATION Meter COMMON to ch
45. Codes reisos oreinen Arn sen e E e Ei F 8 Calibration O ptions Data transfer connections sssesesseeseereseereserersreersrrerereereerese H 2 List of Tables 1 Table 1 1 Getting Started Table 2 1 Table 2 2 Table 2 3 Table 2 4 Table 2 5 Table 2 6 3 Table 3 1 4 Table 4 1 Table 4 2 5 Table 5 1 6 Table 6 1 Table 6 2 Table 6 3 Table 6 4 7 Table 7 1 Table 7 2 Table 7 3 8 Table 8 1 Measurement Concepts Basic measurement capabilities ee eeseeseeeeeeeeeeeeneeeerees 2 2 SCPI commands autoZero 0 cc eeceeeeeeeecesseceececeeeeeeeeeneeens 2 3 Display messages for zero check and zero correct 2 13 SCPI commands zero check and zero correct 0 2 15 SCPI commands input bias current and offset voltage Calibration 00 eee eee ceeeeeceeeeeeeeseeeeeeaeeeneenee 2 18 Summary of measurement considerations 00 0 0 seers 2 19 Volts and O hms Measurements SCPI commands volts and ohms function eee 3 7 Amps Measurements SCPI commands amps function 2 0 eee eeeeeeseeeeeeecneeeeees 4 8 Minimum recommended source resistance values 4 11 Coulombs Measurements SCPI commands coulombs function 0 00 eeeeeeeeeeeeeeees 5 5 Range U nits Digits Rate and Filters Measurement ranges ooo cece eeeeseeeeceeeeeeceseeeeecaeeceeceeaeenaes 6 2 SCPI commands range and digits eee eeeeeeee 6 4 SCPI commands rat
46. E A 13 2 Clearing registers and queues sessseeesseeesrsrestrersrrerereersreeees 13 4 Programming and reading registers lees eeeeeeeeeeeeeeeeeeees 13 5 Programming enable registers eseseseseseeeesersrrererrererrese 13 5 Reading registers oo eee eeeeeeeseeeeeeeeeseceecaecsseeaeenaeeseens 13 6 Status byte and service request SRQ oo eceeeeesceseeceeeeeseeenees 13 7 St tus Dyte register ss ci cieecsbeescsvedassasssotetbvncvscustevumenietbe 13 7 Service request enable register eee ce eeeeeeeeeeeeeeeeeees 13 8 Serial polling and SRQ woe ce eeseeeeceseeeeeeeeeeeeneeeees 13 9 Status byte and service request commands eee 13 9 Status register SOUS ais cciesivsisssoestepnesnensteds riire k KEk eee rsr ERE 13 11 Register bit descriptions sesseesseeessereresrerrrrserrrrerrererree 13 11 Condition registers eeesseeessseeeereesrererrsessrrssrrrrereersreee 13 15 Eyent registers sarne eaa a R ioe 13 16 Event nable r gist rs csrocieesisscorercererscssrsvsodsetarcrissseess 13 17 QUENCES ei a E E E EN 13 18 Output QUCUC 2 25 cesccecscsesscs secescessssccsszeceesstsss cass eine DEE Earn 13 18 Error QUEUE sod vescctlecue cdegsscusecascevecenceszscgeestsecesnissocintosncauees 13 19 Common Commands SCPI Signal O riented Measurement Commands DISPlay FO RMat and SYSTem DISPlay subsystem oe eee eceeseeeceeeeeeceeeeecaeeaecaesaeeeenaes 16 2 FOR Mat subsystem 5 c sccccssesesssesevecesseessc
47. F message READing TIME and STATus CALCulate3 CALCulate3 Subsystem FORMat lt name gt Select buffer statistic MINimum MAXimum MEAN MEAN G SDEViation or PKPK DATA Read the selected buffer statistic H Note SYSTem PRESet and RST have no effect on TRACe commands The listed defaults are power on defaults A TRACe FREE Two values separated by commas are returned The first value indicates how many bytes of memory are available and the second value indicates how many bytes are reserved to store readings Buffer 8 5 B TRACe FEED lt name gt Name parameters e SENSe Raw input readings are stored in the buffer e CALCulate The results of the mX b or percent calculation are stored in the buffer See Section 7 for information on mX b and percent e CALCulate2 Test limit or Rel readings are stored in the buffer See Section 10 for information on limit tests C TRACe FEED CONTrol lt name gt Name parameters e NEXT Enables the buffer and turns on the asterisk annunciator After the buffer stores the specified number of readings the asterisk annunciator turns off e NEVer Disables the buffer D TRACe TSTamp FO RMat lt name gt Name parameters e ABSolute Each timestamp is referenced to the first reading stored in the buffer e DELTa Timestamps provide the time between each buffer reading e The timestamp data element can be included with each buffer
48. Keys Test allows you to test display digit segments and annunciators and check the functionality of front panel keys These tests are accessed by pressing SHIFT and then TEST Refer to Section 20 for details Status and error messages Status and error messages are displayed momentarily During operation and programming you will encounter a number of front panel messages Typical messages are either of status or error variety as listed in Appendix B D efault settings Model 6514 can be restored to one of five default setup configurations factory FACT GPIB and three user saved USRO USR1 and USR2 As shipped from the factory Model 6514 pow ers up to the factory default settings Factory default settings provide a general purpose setup for front panel operation while the GPIB default settings do the same for remote operation Factory and GPIB default settings are listed in Table 1 2 For front panel operation the instrument will power up to whichever default setup was last saved or restored For example if you save the present instrument setup as USRO the instrument will subsequently power up to the USRO setup NOTE At the factory the factory default setup is saved as the USRO USRI and USR2 setups Saving a user setup Perform the following steps to save a user setup 1 Configure Model 6514 for the desired measurement application Press SHIFT and then SAVE to access the save setup menu 3 Use the a or v key to display
49. LO When the test fails the HI LO HI bit pattern is sent to the handler When line 4 goes LO the bit pattern is latched into the register of the handler and the binning oper ation occurs Conversely if the handler requires a high going EOT pulse the EOT line of the digital output must initially be set low off When the EOT line is pulsed high the binning operation occurs Line 4 mode When using a category pulse component handler Model 6514 must be set to the Busy or Busy mode In the Busy mode the idle state for line 4 is LO When the test starts SOT line pulsed line 4 goes HI busy state After the test is finished it goes back to LO For the Busy mode the idle state for line 4 is HI and busy state is LO When using a catagory register component handler Model 6514 must be set for the End of Test mode In this mode Model 6514 sends the EOT pulse to the component handler as previ ously explained Digital output clear pattem After every binning operation the digital output needs to be reset to a clear pattern which serves as a no action condition for the component handler Model 6514 can be programmed to automatically clear the digital output after the pass or fail pattern is sent With auto clear you must specify the required pulse width delay for the pass or fail pattern When not using auto clear you must return the digital output to its clear pattern NOTE With the Busy line 4 mode selected the clear stat
50. Number will be the response NAN is returned as 9 9E37 Timestamp Timestamp references the returned data string to a point in time The times tamp operates as a timer that starts at zero seconds when the instrument is turned on or when the timestamp is reset SYSTem TIME RESet After 99 999 99 seconds the timer resets back to zero and starts over For buffer readings timestamp can be referenced to the first reading stored in the buffer absolute format which is timestamped at 0 seconds or to the time between each stored reading delta format The TRACe TSTamp FOR Mat command is used to select the timestamp format Status The status word provides information about Model 6514 operation The 16 bit sta tus word is sent in decimal form The decimal value has to be converted to the binary equivalent to determine the state of each bit in the word For example if the returned status value is 9 the binary equivalent is 00000001001 Bits 0 and 3 are set The bits are explained as follows Bit 0 OFLO Set to 1 if measurement performed while in over range overflowed reading Bit 1 Filter Set to 1 when measurement performed with the averaging filter enabled Bit 2 Math Set to 1 when measurement performed with CALC1 enabled Bit 3 Null Set to 1 if null for CALC2 is enabled Bit 4 Limits Set to 1 if a limit test CALC2 is enabled Bits 5 and 6 Limit Results Provides limit test results Bit6 Bit 5 0 0 All limit
51. Rate and Filters Range units and digits Provides details on measurement range reading units and display resolution selection Includes the SCPI commands for remote operation e Rate Provides details on reading rate selection Includes the SCPI commands for remote operation e Filters Explains how to configure and control the digital and median filters Includes the SCPI commands for remote operation 6 2 Range U nits Digits Rate and Filters Range units and digits Range The ranges for each measurement function are listed in Table 6 1 The range setting fixed or AUTO is remembered by each function Table 6 1 Measurement ranges V l Q Q 2V 20pA 2kQ 20nC 20V 200pA 20kQ 200nC 200V 2nA 200kQ2 2uC 20nA 2MQ 20uC 200nA 20MQ 2uA 200MQ 20uA 2GQ 200uA 20GQ 2mA 200GQ 20mA The full scale readings for every measurement range are 5 over range For example on the 20V range the maximum input voltage is 21 V Input values that exceed the maximum readings cause the overflow message OVERFLOW to be displayed Manual ranging To select a range press the RANGE A or y key The instrument changes one range per key press The selected range is displayed momentarily If the instrument displays the OVER FLOW message on a particular range select a higher range until an on range reading is dis played Use the lowest range possible without causing an overflow to en
52. Register Decimal 1024 64 32 1 Weights 210 26 29 2 Idle In Idle amp Logical AND Trig Waiting for trigger event OR Logical OR Arm Waiting for arm event Cal Calibrating 13 14 Status Structure Measurement event status The used bits of the measurement event register shown in Figure 13 6 are described as follows e Bit B1 low limit 1 fail LL1F Set bit indicates that the low limit 1 test has failed Bit B2 high limit 1 fail HL 1F Set bit indicates that the high limit 1 test has failed e Bit B3 low limit 2 fail LL2F Set bit indicates that the low limit 2 test has failed Bit B4 high limit 2 fail H L2F Set bit indicates that the high limit 2 test has failed Bit B5 limits pass LP Set bit indicates that all limit tests passed Bit B6 reading available R AV Set bit indicates that a reading was taken and processed Bit B7 reading overflow ROF Set bit indicates that the volts amps ohms or cou lombs reading exceeds the selected measurement range of Model 6514 e Bit B8 buffer available BAV Set bit indicates that there are at least two readings in the buffer Bit B9 buffer full BFL Set bit indicates that the buffer is full Figure 13 6 CONDition ___ BFL BAV ROF RAV LP JHL2F LL2F HLIF LLIF Measurement Measurem
53. Returns how many times a 6514 has been calibrated Voltage Offset correction Current Offset correction Remote calibration overview The steps below outline the general procedure for calibrating the Model 6514 using remote commands Refer to Section 19 for details on calibration steps calibration points and test equip ment connections 1 Send the following command to unlock calibration CAL PROT CODE KI0065 14 Note that the above command uses the factory default code 2 Perform current and voltage offset correction by sending the following commands CAL UNPR IOFF CAL UNPR VOFF Be sure the appropriate connections are made to the INPUT jack before sending each command cap for IOFF short for VOFF Calibration Options H 5 3 Send the appropriate commands to select the function and range to be calibrated For ex ample the following commands select the volts function and the 2V range SENS FUNC VOLT SENS VOLT RANG 2 4 Make appropriate connections then send the commands for each calibration point for the selected function and range For example send the following commands for the 2V range CAL PROT SENS 0 CAL PROT SENS 2 CAL PROT SENS 2 NOTE Be sure the appropriate calibration signal is applied to the INPUT jack before send ing the command for each calibration point See Section 19 for details 5 Repeat steps 3 and 4 for each function and range 6 After all functions and
54. SYSTem PRESet have no effect on the display circuitry Pressing LOCAL or cycling power enables ON the display circuit 2 RST and SYSTem PRESet have no effect on a user defined message Pressing LOCAL or cycling power cancels all user defined messages 3 RST and SYSTem PRESet have no effect on the state of the message mode Pressing LOCAL or cycling power disables OFF the message mode Table 17 3 FORMat command summary Default Command Description parameter Ref SCPI FORMat Sec 16 DATA lt type gt lt length gt Specify data format ASCii REAL 32 or SREal ASC v DATA Query data format v ELEMents lt item list gt Specify data elements READing TIME and All 3 STATus ELEMents Query data format elements BORDer lt name gt Specify byte order NORMal or SWAPped see Note vV BORDer Query byte order vV SREGister lt name gt Select data format for reading status registers ASC Sec 13 ASCii HEXadecimal OCTal or BINary SREGister Query format for reading event registers SOURce2 lt name gt Select data format for reading output patterns ASC Sec 10 SOURce2 ASCii HEXadecimal OCTal or BINary Query format for reading output patterns Note RST default is NORMal SYSTem PRESet default is SWAPped 17 6 SCPI Reference Tables Table 17 4 SENSe command summary Default Command Description parameter Ref SCPI SENSe 1 FUNCtion lt name gt Select function
55. Signal pin number pin number DCD data carrier detect 1 8 RXD receive data 2 3 TXD transmit data 3 2 DTR data terminal ready 4 20 GND signal ground 5 7 DSR data set ready 6 6 RTS request to send 7 4 CTS clear to send 8 5 RI ring indicator 9 22 Error messages See Appendix B for RS 232 error messages 12 19 13 Status Structure Overview Provides an operational overview of the status structure for Model 6514 Clearing registers and queues Covers the actions that clear reset registers and queues Programming and reading registers Explains how to program enable registers and read any register in the status structure Status byte and service request SR Q Explains how to program the status byte to generate service requests SRQs Shows how to use the serial poll sequence to detect SRQs Status register sets Provides bit identification and command information for the four status register sets standard event status operation event status measurement event sta tus and questionable event status Queues Provides details and command information on the output queue and error queue 13 2 Status Structure Overview Model 6514 provides a series of status registers and queues allowing the operator to monitor and manipulate the various instrument events The status structure is shown in Figure 13 1 The heart of the status structure is the status byte register This regi
56. Status byte and service request commands 13 9 Status byte register 13 7 Status register sets 13 11 Status Structure 13 1 Store 8 2 Storing readings in buffer E 5 Surface insulation resistance SIR 4 15 System electrometer features 1 4 SYSTem subsystem 16 8 Taking readings using the READ command E 6 Temperature and relative humidity 19 2 Test circuit leakage 3 2 Test considerations 18 8 Test fixture 2 9 Test summary 18 8 Triboelectric effects C 3 Trigger model configuration front panel 9 7 Trigger model operation 9 4 Trigger models 9 2 Triggering 9 1 Typical command sequences F 11 Unaddress commands F 9 Units 6 4 V Drop and I Source for ohms 3 6 Verification limits 18 6 Verification test requirements 18 3 Voltage burden 4 9 Volts and ohms measurement considerations 3 9 Volts and ohms measurement procedure 3 4 Volts and Ohms Measurements 3 1 Volts calibration 19 8 Volts measurement accuracy 18 10 Warm up period 2 2 18 3 19 2 Warranty information 1 2 Zero check 2 13 Zero check and zero correct 2 13 Zero check hop and auto discharge hop 5 7 Zero correct 2 14 Service Form Model No Serial No Date List all control settings describe problem and check boxes that apply to problem Q Intermittent Analog output follows display Particular range or function bad specify IEEE failure Obvious problem on power up Batteries and fuses are OK Front panel operational U All
57. Table F 6 Model 6514 interface function codes Code Interface function SH1 Source Handshake capability AHI Acceptor Handshake capability T5 Talker basic talker talk only serial poll unaddressed to talk on LAG L4 Listener basic listener unaddressed to listen on TAG SR1 Service Request capability RL1 Remote Local capability PPO No Parallel Poll capability DC1 Device Clear capability DT1 Device Trigger capability CO No Controller capability El Open collector bus drivers TEO No Extended Talker capability LEO No Extended Listener capability The codes define Model 6514 capabilities as follows SH Source Handshake Function SH1 defines the ability of the instrument to initiate the transfer of message data over the data bus AH Acceptor Handshake Function AH1 defines the ability of the instrument to guar antee proper reception of message data transmitted over the data bus T Talker Function The ability of the instrument to send data over the bus to other devices is provided by the T function Instrument talker capabilities T5 exist only after the instrument has been addressed to talk L Listener Function The ability for the instrument to receive device dependent data over the bus from other devices is provided by the L function Listener capabilities L4 of the instrument exist only after it has been addressed to listen SR Service R equest Function SR1 defines the ability
58. a high input imped ance and low output impedance is used Since the center conductor HI and the inner shield Guard of the cable are at virtually the same potential the potential across R is zero so no cur rent flows Also with a zero potential across C4 there is no capacitor charging process to slow down the measurement response For the volts and ohms functions the input of Model 6514 places the driven guard on the inner shield of the triax cable when GRD is enabled Source_ Center Triax Cable Conductor HI Rs i Hm x Inner Shield LO a Guard 6514 Input 150kQ 3 14 Volts and Ohms Measurements Application Capacitor dielectric absorption Dielectric absorption occurs when randomly oriented permanent dipoles of molecules with a capacitor dielectric are aligned by an applied electric field After a capacitor has been discon nected from a discharge circuit a residual charge remains on the capacitor and a voltage will be re established across the capacitor terminals For timing and integrating applications dielectric absorption or a residual capacitor voltage can seriously degrade the accuracy of the circuit Thus a capacitor s dielectric absorption must be known and compensated for in circuits where capacitance tolerance is a significant factor in circuit accuracy Dielectric absorption is not normally specified by a manufacturer since its importance is applicat
59. calibration DATES Displays calibration and due dates UNLOCK Unlocks calibration using code LOCK Locks cal exits to the main menu SAVE Saves calibration constants Press SHIFT then CAL to access Use up or down RANGE to scroll through selections Aborting calibration You can abort the calibration procedure at any time by pressing the EXIT key 19 6 Calibration Current and charge calculations When calibrating the 20pA 2uA current ranges and all charge ranges you must calculate the actual current or charge values from the applied calibrator voltages and the characterized Model 5156 Calibration Standard resistor and capacitor values You can either calculate these values manually as in this section or automatically as covered below Manual calculations Current calculations Calibration currents are calculated as follows I V R Where I calibration current V calibrator voltage R actual standard resistor value For example assume you are calibrating the 20pA range using a 2V calibrator voltage with an actual 100 5GQ standard resistor value The actual calibration current is 2V 100 5GQ 19 9004pA Charge calculations Calibration charge values are calculated as follows Q CV Where Q calibration charge C actual standard capacitance value V calibrator voltage For example the 200nC range calibration charge value using 2V with a 99 5nF standard capacitance value is 2V x 99 5nF 199nC A
60. calibration code 1 Press SHIFT then CAL The instrument will display the following CAL RUN Use the up or down RANGE key to display the following CAL UNLOCK Press ENTER The instrument will prompt for the present calibration code CODE Calibration 19 19 4 Enter the present calibration code on the display Factory default 006514 Use the up and down RANGE keys to select the letter or number and use the left and right arrow keys to choose the position Press ENTER to complete the process and the unit will display NEW CODE Y N 5 Select Y then press ENTER The unit will prompt for the new code CODE 000000 6 Enter the new code then press ENTER 7 Using the LOCK selection in the calibration menu lock out calibration after changing the code Resetting the calibration code If you forget the calibration code you can unlock calibration by shorting together the CAL pads which are located on the display circuit board inside the unit Doing so will also reset the code to the factory default 006514 Displaying calibration dates To display calibration dates at any time 1 From normal display press SHIFT then CAL The unit will display the following CAL RUN 2 Use either RANGE key to select CAL DATES then press ENTER Model 6514 will dis play the last calibration date for example DATE 06 15 98 3 Press ENTER to view the calibration due date for example NDUE 06 15 99 4 Press EXIT to retu
61. calibration resistance INPUT 2KOHM Press ENTER The unit will prompt for the actual resistance 2 000000KOHM Connect the resistance calibrator to the Model 6514 INPUT jack as shown in Figure 19 5 Select the 1 9kQ calibrator resistance Adjust Model 6514 display to agree with the actual calibration resistance then press ENTER to complete calibration of the present range Press EXIT to return to normal display Repeat steps 3 through 10 for the 2M range using the 1 9MQ calibrator resistance See Table 19 7 Calibration 19 17 12 Disconnect the resistance calibrator and connect the 1GQ calibration standard resistor to Model 6514 INPUT jack as shown in Figure 19 6 Be sure to remove the link between Model 5156 SHIELD and CHASSIS terminals Also connect Model 5156 CHASSIS ter minal to Model 6514 COMMON jack WARNING Hazardous voltages may be present on Model 5156 SHIELD and OUTPUT terminals 13 Using the GRD key enable Model 6514 guard mode 14 Repeat steps 3 through 10 for the 2GQ range Be sure to set Model 6514 display to the actual standard resistance value Figure 19 6 Model 5156 Calibration Standard Model 6514 Electrometer Connections for ohms calibration 2GQ range 1062 inF 100nF OUTPUT Remove SHIELD to CHASSIS link Connect SHIELD to 6514 COMMON To Shield Triax Cable Note Enable guard mode Table 19 7 Ohms calibration summary Mo
62. data to any IBM PC 16 8 SYSTem subsystem DISPlay FORMat and SYSTem Table 16 3 SCPI commands system Command Description Default Ref SYSTem ZCHeck lt b gt Enable or disable zero check ON Sec 2 ZCORrect Zero correct Sec 2 STATe lt b gt Enable or disable zero correct OFF ACQuire Acquire a new zero correct value PRESet Return to SYSTem PRESet defaults A LFRequency lt freq gt Select power line frequency 50 or 60 Hz Sec 1 AZERo Path to control autozero Sec 2 STATe lt b gt Enable or disable autozero ON TIME Timestamp RESet Reset timestamp to 0 seconds B POSetup lt name gt _ Select power on setup RST PRESet or SAVx C where x 0 to 4 VERSion Query SCPI revision level D ERRor Read messages in error queue see Note Sec 13 NEXT Return and clear oldest error code and message ALL Return and clear all errors code and message COUNt Return the number of errors CODE Error code numbers only NEXT Return and clear oldest error code only ALL Return and clear all errors codes only CLEar Clear messages from error queue Sec 13 KEY lt NRf gt Simulate key press see Figure 16 3 E RS 232 interface Sec 12 LOCal Take Model 6514 out of remote RS 232 only REMote Put Model 6514 in remote RS 232 only RWLock Enable or disable local lockout RS 232 only Note Clearing the error queue power up and CLS clears the error queue RST SYST
63. disables Zero Check ZCOR Enables disables Zero Correct GRD Enables disables Guard 1 6 Getting Started Shifted V D ROP AUTO DIS GPIB RS 232 Middle Row Unshifted AVG MEDN REL LIM IT DIGIT RATE lt qand p Shifted MX B VAL CONF LIM UNITS NPLC Bottom Row Unshifted STO RE RCLL DELAY DAMP HALT TRIG EXIT ENTER Shifted TEST CAL SAVE SETU P CONF ARM CONF TRIG 3 Range keys A v AUTO Enables disables V drop measurements for Q function Sets and enables disables Auto Discharge for charge measurements Configures and enables disables GPIB interface Configures and enables disables RS 232 interface Configures and enables disables digital filter Configures and enables disables median filter Enables disables Relative Rel Performs configured limit tests Sets display resolution Selects measurement rate Controls cursor position for making selections or editing values Configures and enables disables mX b math function Configures and enables disables Percent math function Sets Rel value and enables Rel Configures limit tests Selects engineering units for scientific notation for display readings Set rate by setting PLC value Sets the number of readings to store and enables the buffer Displays stored readings including maximum minimum peak to peak average and standard deviation The A and range keys scroll through the buffer and the lt orp
64. electrostatic inter ference include 1 Shielding Possibilities include a shielded room a shielded booth shielding the sensi tive circuit and using shielded cable The shield should always be connected to a solid connector that is connected to signal low If circuit low is floated above ground observe safety precautions and avoid touching the shield Meshed screen or loosely braided cable could be inadequate for high impedances or in string fields Note however that shielding can increase capacitance in the measuring circuit possibly slowing down response time 2 Reduction of electrostatic fields Moving power lines or other sources away from the experiment reduces the amount of electrostatic interference seen in the measurement Magnetic fields A magnetic field passing through a loop in a test circuit will generate a magnetic EMF volt age that is proportional to the strength of the field the loop area and the rate at which these factors are changing Magnetic fields can be minimized by following these guidelines e Locate the test circuit as far away as possible from such magnetic field sources as motors transformers and magnets e Avoid moving any part of the test circuit within the magnetic field e Minimize the loop area by keeping leads as short as possible and twisting them together Electromagnetic Interference EMI The electromagnetic interference characteristics of the Model 6514 comply with the electro ma
65. enabled when a different function is selected With zero check disabled it will remain disabled when the volts amps or coulombs function is selected NOTE Zero check will always enable whenever the ohms function is selected Zero check is enabled by pressing the ZCHK key Pressing ZCHK a second time disables zero check NOTE To ensure proper operation always enable zero check before changing functions For coulombs enabling zero check dissipates the charge That is the charge reading is reset to zero When zero check is disabled a sudden change in the charge reading zero check hop occurs This effect can be cancelled by enabling Relative REL immediately after zero check is disabled Relative is explained in Section 7 2 14 Measurement Concepts Figure 2 10 Equivalent input impedance with zero check enabled For volts amps and ohms leave zero check enabled when connecting or disconnecting input signals For coulombs disable zero check before connecting the input signal If zero check is left enabled when you connect the input signal the charge will dissipate through the 1OMQ resistor see Figure 2 10 C IN Input 1mo gt Cin 10pF Volts and Ohms Ze 1kQ mA 1MQ 1000pF uA 1GQ 10pF nA 1TQ 1pF pA gt Cin Input 10M Ze Ciy 10pF Amps Cin Input 10M2 Zp f gt LJ Cin 10pF lin Ohms Zp 1kQ KQ 1MQ 1000pF M Q9
66. external feedback mode The display will show the voltage measured at the out put of the input preamplifier PREAMP OUT NOTE To disable external feedback press XFBK and select the OFF option 11 14 Digital I O Analog O utputs and External Feedback Figure 11 8 Input LO Inner Shield Shielded fixture Input HI Center Conductor construction LO 2 4 To 6514 From Signal input HI To Preamp Out Feedback Element Ww A Construction Feedback Element r TERN BA gt gt Preamp Out i i HI i To Ranging 1 Amp and A D Lo gt 40 aii GND 1 i 5 gt GND 6514 Input S Amp YN Shielded See rh Fixture 237 ALG 2 7078 TRX 3 Cable Cable B Equivalent Circuits Parts List Item Description MFR Part Number 1 Shielded Fixture Pomona 2390 2 Female Triaxial Keithley 7078 TRX TBC 3 Banana Jack Keithley BI 9 2 4 Triaxial Cable Keithley 237 ALG 2 5 Triaxial Cable Keithley 7078 TRX 3 Digital I O Analog Outputs and External Feedback 11 15 Logarithmic currents The use of a diode junction in the external feedback path permits a logarithmic current to voltage conversion This relationship for a junction diode is given by the equation V mkT q In Ig Irs where q unit of charge 1 6022 x 10 k Boltzmann s constant 1 3806 x 10 23 T temperature
67. group press SHIFT and then the RANGE key See Section 6 for details on range Step 3 If desired set and enable auto discharge See Auto Discharge to set an auto discharge level and enable it Step 4 Connect the input cable to Model 6514 open input Make sure that the test circuit is not connected to the input Step 5 Disable zero check and press the REL key When zero check is turned off a charge may be induced on the input Pressing the REL key zeroes the display See Zero Check Hop in Coulombs Measurement Considerations in this section Details on Relative are provided in Section 7 NOTE Ifthe zeroed reading drifts significantly after REL is enabled disable REL and toggle zero check on and off until drift is minimized Enable zero check and repeat Step 5 5 4 Coulombs Measurements Step 6 Connect the charge to be measured to the electrometer Basic connections for amps measurements are shown in Figure 5 1 NOTE See Connection Basics in Section 2 for fundamental information on making con nections to the electrometer input Figure 5 1 Red HI Typical connections for coulombs Metal Noise Shield O ptional arder Back to Cable Input LO connected to shield VICE BY QUALIFIED PERSONNEL ONLY a KEITHLEY AQ5 WARNIM Gio INTERNAL OPERATO IEEE 488 PREAMP OUT 2V ANALOG COMMON CHASSIS eS EAEL ME 250V PK OUTPUT D cwe owo o INPU
68. has a 250V compliance To prevent electric shock always enable zero check to disable the test signal before making or break ing connections to DUT SCPI programming Table 3 1 SCPI commands volts and ohms function Commands Description Default Ref SENSe SENSe Subystem FUNCtion lt name gt Select function VOLTage or RESistance VOLT A DATA Return latest raw reading B VOLTage GUARd lt b gt Enable or disable guard OFF C RESistance GUARd lt b gt Enable or disable guard OFF C INITiate Trigger one or more readings B READ Trigger and return reading s B A SENSe FUNCtion lt name gt Parameters VOLTage Volts function RESistance Ohms function CURRent Amps function CHARge Coulombs function Note that the parameter names are enclosed in single quotes However double quotes can instead be used Each measurement function remembers its own unique range setting 3 8 Volts and Ohms Measurements B SENSe D ATA This command does not trigger a reading It simply returns the last raw reading string It will not return the result of any instrument calculation The reading reflects what is applied to the input To return a fresh new reading you can send the INITiate command to trigger one or more readings before sending DATA Details on INITiate are provided in Section 9 While Model 6514 is busy performing measurement
69. in parallel will maintain a low impedance across a wide frequency range Keep in mind however that such filtering may have detrimental effects such as increased response time on the measurement DDC Emulation Commands D 2 DDC Emulation Commands DDC language The Model 6514 can be configured to accept device dependent commands DDCs of the Keithley Model 6512 617 or 617 HIQ electrometer The commands for controlling the Model 6514 with the DDC language are provided in Table D 1 For details on Model 6512 617 and 617 HIQ operation refer to the appropriate instruction manual Since the architecture of the Model 6514 differs from that of the other electrometers some commands are different and cannot be used Be sure to refer to the notes at the end of the table for information on command restrictions CAUTION TheDDC language is intended to be used only over the IE E E 488 bus Using front panel controls in conjunction with this language may cause erratic operation In this case results cannot be guaranteed Table D 1 Device dependent command summary Mode Command _ Description Note Calibration Value none A calibration commands not supported Reading Mode BO Electrometer Bl Buffer reading B2 Maximum reading B3 Minimum reading Zero Check CO Zero Check off Cl Zero Check on Function FO Volts F1 Amps F2 Ohms F3 Coulombs F4 External Feedback Data Format GO Reading with prefix NDCV 1 23456E 00 Gl Rea
70. in the instrument s one year accuracy specifications You can perform these verification procedures e When you first receive the instrument make sure that it was not damaged during shipment e Verify that the unit meets factory specifications e Determine if calibration is required e Following calibration make sure it was performed properly WARNING _ Theinformation in this section is intended only for qualified service person nel Do not attempt these procedures unless you are qualified to do so Some of these procedures may expose you to hazardous voltages which could cause personal injury or death if contacted U sestandard safety precautions when working with hazardous voltages NOTE Ifthe instrument is still under warranty and its performance is outside specified lim its contact your Keithley representative or the factory to determine the correct course of action Performance Verification 18 3 Verification test requirements Be sure that you perform the verification tests e Under the proper environmental conditions e After the specified warm up period e Using the correct line voltage e Using the proper test equipment e Using the specified test signals and reading limits Environmental conditions Conduct your performance verification procedures in a test environment with e An ambient temperature of 18 28 C 65 82 F e A relative humidity of less than 70 unless otherwise noted Warm up period A
71. increases measurement speed However the zero and gain reference points will eventually drift resulting in inaccurate readings of the input signal It is recommended that autozero only be dis abled for short periods of time Autozero cannot be disabled from the front panel however it can be enabled from the front panel by restoring factory or GPIB default conditions M easurement Concepts 2 3 SCPI programming Table 2 2 SCPI commands autozero Command Description Default SYSTem SYSTem Subsystem AZERo STATe lt b gt Enable or disable autozero ON Programming example The following command sequence will perform one zero corrected amps measurement SYST AZER OFF Disable autozero SYST AZER ON Enable autozero Connection fundamentals The following provides important fundamental information on input connections to Model 6514 Typical connection drawings are included with the various measurement procedures pro vided in subsequent sections of this manual Input connector The rear panel INPUT connector is a 3 lug female triax connector that will mate to a cable terminated with a male triax connector 2 4 Measurement Concepts Input configurations As shown in Figure 2 1 the input connector can be configured in two ways With guard off Figure 2 1A input low is connected to the inner shell of the connector This configuration is used for Amps Coulombs unguarded Volts and ungu
72. letters A Z MXB MUNits Query units PERCent Configure percent math calculation REFerence lt NRf gt Specify reference value 9 99999e20 to 1 0 9 99999e20 ACQuire Use input signal as reference value PERCent Query reference value STATe lt b gt Enable or disable CALC1 calculation OFF vV SCPI Reference Tables 17 3 Table 17 1 cont CALCulate command summary NOTE The lt NDN gt and lt NRf gt parameter values for the SOURce2 command are provided at the end of this table Default Command Description parameter Ref SCPI STATe Query state of CALC1 calculation vV DATA Return all CALC results triggered by INITiate vV LATest Return last latest reading CALCulate2 Path to configure and control limit testing CALC2 Sec 10 V FEED lt name gt Select input path for limit testing CALCulate 1 SENS vV or SENSe 1 FEED Query input path for limit tests vV LIMit 1 Limit 1 Testing v UPPer Configure upper limit vV DATA lt n gt Set limit 9 99999e20 to 9 99999e20 1 0 v DATA Query upper limit vV SOURce2 lt NDN gt or Specify 4 bit output fail pattern 15 V lt NRf gt SOURce2 Query output pattern value vV LOWer Configure lower limit vV DATA lt n gt Set limit 9 99999e20 to 9 99999e20 1 0 v DATA Query lower limit v SOURce2 lt NDN gt or Specify 4 bit output fail pattern 15 vV lt NRf gt SOURce2 Query output pattern value vV STAT
73. mX b and Percent A FEED lt name gt Specify reading to Rel With SENSe 1 selected the Rel operation will be performed on the input signal With CALCulate 1 selected the Rel operation will be performed on the result of the Percent or mX b calculation B DATA and DATA LATest With Rel enabled these commands will return one or more Rel ed readings They will not trigger fresh new readings Use the INITiate command to trigger new readings see Section 9 for details on INITiate If the instrument is programmed to perform a finite number of measurements the DATA command will return all the Rel ed readings after the last reading is taken The DATA LATest command will only return the last latest Rel ed reading If the instrument is programmed to perform an infinite number of measurements arm count or trigger count set to infinite you cannot use the DATA command to return Rel ed readings However you can use the DATA LATest command to return the last Rel ed reading after abort ing the measurement process After sending the INITiate command to start the measurement process use the ABORt command to abort the measurement process then use DATA LATest to return to the last Rel ed reading Programming example relative This program fragment establishes a 1V baseline for voltage measurements FUNC VOLT Select V function CALC2 NULL OFFS 1 Set Rel value of
74. make sure the calibrator output is turned on and set the output to OV 5 Press SHIFT then CAL then press ENTER at the CAL RUN prompt The unit will prompt for the positive full scale calibration point 20nC CAL 6 Press ENTER The unit will prompt for the positive full scale calibration value 20 0000nC 7 Set the calibrator voltage to 20 00000V Compute the actual charge from the calibrator voltage and actual capacitance value Q CV Adjust Model 6514 display to agree with that charge value then press ENTER 8 Model 6514 will prompt for the zero calibration point 2nC ZERO 9 Press ENTER to complete zero calibration for the present range and then set the calibrator to output OV Model 6514 will next prompt for the negative full scale calibration point 20nC CAL pa Calibration 19 15 10 Press ENTER Model 6514 will prompt for the negative full scale charge value 20 0000nC 11 Set the calibrator output voltage to 20 00000V Calculate the actual charge from the cal ibrator voltage and actual standard capacitor value Q CV Adjust Model 6514 display to agree with the calculated charge value then press ENTER to complete calibration of the present range 12 Press EXIT to return to normal display 13 Repeat steps 4 through 12 for the 200nC through 20uC ranges using Table 19 6 as a guide Table 19 6 Coulombs calibration summary Model 6514 range Calibrator voltage Standard capacitance Calibr
75. mopona uenon E ER RS 20 4 Specifications Status and Error Messages General Measurement Considerations Measurement considerations ccccccccecessseceeceescececeeesseeeeees C 2 Ground LOOPS sissscssisssscteenscassesesssesocsedaciess atasespdsvensssbasesseedes C 2 Triboelectric effects oo ecccesssccececssssceceecssssceeecesesseseeees C 3 Piezoelectric and stored charge effects 1 0 0 0 eee C 3 Electrochemical effects cccccccccecessceceecessscesecesesseeeeees C 4 Humidity oeieo iietra aenean eee aaaeei Eere tree C 4 DDta reer er eereercre ree orereere renee cerentr er reerier siete rere C 4 Electrostatic interference cccccccecesssceceeceesssececeeesssaneeees C 4 Magnetic elds ssicsscccsssesvsecegecsbassseveetatessaescasesssacseasssbaessnesen C 5 Electromagnetic Interference EMI eseeeeeseceeneeeeees C 5 DDC Emulation Commands DDC Jan guages ciciwusiaieiain in e EE Ei D 2 Example Programs Programming examples 00 eeeeesseeeeecseceececeeeceeeceeeecnseeeneeeee E 2 Changing function and range cee ee eeeeeeeeeeeeeeeeeeeeeaee E 2 One shot triggering eee ee cece ceseeeeceeeeeeceeeeeeeeeeeeeeeneeaee E 3 Generating SRQ on buffer full oo ee eee eee ceeeeeeteeteeeeees E 4 Storing readings in buffer oo eee eeeseseeeeeeecneeseeeeeeeenees E 5 Taking readings using the READ command 00 000 E 6 Controlling the Model 6514 via the RS 232 COM port E 7 IEEE 488 Bus O verview Intr
76. of 1 is 1V on the 2V range 1V on the 20V range and 1V on the 200V range Note that function changes dis ables Rel When a Rel value is larger than the selected range the display is formatted to accommodate the Rel ed reading However this does not increase the maximum allowable input for that range An over range input signal will still cause the display to overflow For example on the 20V range Model 6514 still overflows for a 20 1 V input NOTE Relcan be used on the result of the percent or mX b calculations However Rel will disable whenever a math function is enabled or disabled Setting and controlling relative From the front panel there are two ways to set the Rel value You can use the input reading as the Rel value or you can manually key in the Rel value REL key When the REL key is used to enable Rel the present display reading is used as the Rel value Perform the following steps to set a Rel value 1 Display the reading you want as the Rel value This could be a zero offset reading that you want to null out or it could be an applied level that you want to use as a baseline 2 Press REL The REL annunciator turns on and subsequent readings will be the difference between the actual input and the Rel value 3 To disable REL press the REL key a second time or select a different measurement func tion The REL annunciator turns off NOTE When Rel is disabled the Rel value is remembered and can be reinst
77. of the overlapped command are still in progress The WAI command is used to suspend the execution of subsequent commands until the device operations of all previous overlapped commands are finished The WAI command is not needed for sequential commands O15 SCPI Signal O nented M easurement Commands 15 2 SCPI Signal O riented Measurement Commands The signal oriented measurement commands are used to acquire readings You can use these high level instructions to control the measurement process These commands are summarized in Table 15 1 NOTE The readings acquired by these commands depend on which data elements are selected see FORMat Subsystem in Section 16 for details Table 15 1 Signal oriented measurement command summary Command Description Ref CONFigure lt function gt Places Model 6514 in a one shot measurement A mode for the specified function CONFigure Queries the selected function FETCh Requests the latest reading s B READ Performs an INITiate and a FETCh C MEASure lt function gt Performs a CONFigure lt function gt and a READ D A CONFigure lt function gt Configure Model 6514 for one shot measurements lt function gt VOLTage DC Configure voltage CURRent DC Configure current RESistance Configure resistance CHARge Configure charge This command configures the instrument for one shot measurements on the specified func tion Eac
78. or 2V ANALOG OUTPUT to earth while floating the input may damage the instrument 2V analog output The 2V analog output provides a scaled 2V output that is non inverting in the volts mode Connections for using this output are shown in Figure 11 5 For a full range input i e 2V on the 2V range the output will be 2V Example analog outputs are listed in Table 11 2 The 2V analog output signal is not corrected during calibration Gain errors of up to 15 may appear at this output depending on function and range The output impedance is 10k To minimize the effects of loading the input impedance of the device connected to the 2V analog output should be as high as possible For example for a device that has an input impedance of 10M the error due to loading will be approximately 0 1 NOTE _ Rel and the result of mX b or percent have no affect on the analog output The 2V analog output is scaled only to the actual input Table 11 2 Example 2V analog output values Analog output Range Applied signal value nominal 20pA 10 5pA 1 05V 2uA 1 65pA 1 65V 200mV 140mV 1 4V 200V 36V 0 36V 200kQ 175kQ 1 75V 20nC 19nC 1 9V Output values are within 15 of nominal value 11 8 Digital I O Analog O utputs and External Feedback Figure 11 5 Typical 2V analog output connections Model 1683 Model 6514 Rear Panel Test Lead kit Measuring Device i e Chart recorder
79. programmed to generate an SRQ and command queries can be per formed to check for specific error conditions GPIB status indicators The REM remote TALK talk LSTN listen and SRQ service request annunciators show the GPIB bus status Each of these indicators is described below REM This indicator shows when the instrument is in the remote state REM does not necessarily indicate the state of the REM line as the instrument must be addressed to listen with REM true before the REM indicator turns on When the instrument is in remote all front panel keys except for the LOCAL key are locked out When REM is turned off the instrument is in the local state and front panel operation is restored TALK This indicator is on when the instrument is in the talker active state Place the unit in the talk state by addressing it to talk with the correct MTA My Talk Address command TALK is off when the unit is in the talker idle state Place the unit in the talker idle state by sending a UNT Untalk command addressing it to listen or sending the IFC Interface Clear command LSTN This indicator is on when Model 6514 is in the listener active state which is activated by addressing the instrument to listen with the correct MLA My Listen Address command LSTN is off when the unit is in the listener idle state Place the unit in the listener idle state by sending UNL Unlisten addressing it to talk or sending the IFC Interface Cl
80. ranges or functions are bad UQ Checked all cables Display or output check one Drifts Unable to zero Unstable Overload Will not read applied input Calibration only Certificate of calibration required Data required attach any additional sheets as necessary Show a block diagram of your measurement including all instruments connected whether power is turned on or not Also describe signal source Where is the measurement being performed factory controlled laboratory out of doors etc What power line voltage is used Ambient temperature F Relative humidity Other Any additional information If special modifications have been made by the user please describe Be sure to include your name and phone number on this service form Specifications are subject to change without notice All Keithley trademarks and trade names are the property of Keithley Instruments Inc All other trademarks and trade names are the property of their respective companies KEITHLEY A GREATER MEASURE OF CONFIDENCE Keithley Instruments Inc Corporate Headquarters 28775 Aurora Road Cleveland Ohio 44139 440 248 0400 Fax 440 248 6168 1 888 KEITHLEY 534 8453 wwwkeithley com Belgium Sint Pieters Leeuw 02 363 00 40 Fax 02 363 00 64 www eithley n China Beijing 8610 82251886 Fax 8610 82251892 wwwkeithley com cn Finland Helsinki 09 5306 6560 Fax 09 5306
81. reading see Ref F E TRACe DATA 1 The response message will include one to three data elements for each stored reading Use the FORMat ELEMents command see Ref F to specify the elements 2 Reading an empty buffer will result in the ERROR 230 display message 3 Buffer data can be sent in the binary format See the FORMat Subsystem in Section 16 for details F FORMatELEMents lt list gt 1 List parameters e READing Includes the buffer reading in each data string e TIME Includes the timestamp for each reading Timestamp can be in the absolute or delta format see Ref D e STATus Includes a status word for each reading It provides status information on instrument operation See FORMat Subsystem in Section 16 for details 2 Atleast one data element must be in the list Listed elements must be separated by a comma i e FORMat ELEMents READing TIME Elements not listed will not accompany the response message for TRACe DATA 8 6 Buffer G CALCulate3 FO RMat lt name gt This command selects the statistic to be returned by CALCulate3 DATA see Ref H Name parameters MINimum Select the lowest reading stored in the buffer MAXimum Select the largest reading stored in the buffer MEAN Select the mean average statistic for the readings stored in the buffer SDEViation Select the standard deviation statistic for the readings stored in the buffer PKPK Select the peak to peak
82. set the source sets DAV low indicating to accepting devices that the byte on the data lines is now valid NRFD will then go low and NDAC will go high once all devices have accepted the data Each device will release NDAC at its own rate but NDAC will not be released to go high until all devices have accepted the data byte The previous sequence is used to transfer both data talk and listen addresses as well as mul tiline commands The state of the ATN line determines whether the data bus contains data addresses or commands as described in the following paragraphs DATA x J SOURCE DAV SOURCE VALID ALL READY ACCEPTOR NRFD ua ALL ACCEPTED NDAC ACCEPTOR Bus commands EEE 488 Bus Overview F 7 The instrument may be given a number of special bus commands through the IEEE 488 interface The following paragraphs briefly describe the purpose of the bus commands which are grouped into the following three categories 1 Uniline commands Sent by setting the associated bus lines true For example to assert REN Remote Enable the REN line would be set low true 2 Multiline commands the ATN line true low 3 Common commands Commands that are common to all devices on the bus sent with ATN high false 4 SCPI commands Commands that are particular to each device on the bus sent with ATN false General bus commands which are sent over the data lines with These bus commands and their gene
83. source capacitance will also affect the noise performance of the Model 6514 ammeter In general as source capacitance increases the noise also increases To see how changes in source capacitance can affect noise gain again refer to the simplified ammeter model in Figure 4 5 The elements of interest for this discussion are the capacitance Cs and the feedback capac itance Cp Taking into account the capacitive reactance of these two elements the previous noise gain formula must be modified as follows Output Vyoisp Input Vyorsell Zp Zs Here Zp represents the feedback impedance made up of Cp and Ryp while Zs is the source impedance formed by Rg and Cs Furthermore R Zp Se 2xfR Cp 1 and R Z gt 2afRsCs 1 Note that as C increases in value Z decreases in value thereby increasing the noise gain Again at the point where Zs Z the input noise is amplified by a factor of two The maximum value of source capacitance Cs for Model 6514 ammeter is 10 000pF You can however usually measure at higher source capacitance values by inserting a resistor in series with the ammeter input but remember that any series resistance will increase the voltage burden by a factor of Im Rserw s For example the range of resistance listed in Table 4 2 will result in voltage burden values in range of 1mV to 1V A useful alternative to a series resistor is a series diode or two diodes in parallel back to back The diodes can
84. statistic for readings stored in the buffer Peak to Peak is calculated as follows PKPK MAXimum MINimum H CALCulate3 D ATA 1 If the number of data points in the buffer is one or none CALCulate3 DATA will result in an error 230 If there is a lot of data in the buffer some statistic operations may take too long and cause a bus time out error To avoid this send calc3 data and then wait for the MAV message available bit in the Status Byte Register to set before addressing the Model 6514 talk see Section 13 Programming example The following program fragment stores 20 readings into the buffer and then calculates the mean average on the buffer readings Select data elements RST Return 6514 to RST defaults FORM ELEM READ TIME Select reading and timestamp Store and Recall Readings TRAC POIN 20 Set buffer size to 20 RAC FEED SENS Store raw input readings RAC FEED CONT NEXT Start storing readings TRAC DATA Request all stored readings Acquire Mean Statistic for Buffer Readings CALC3 FORM MEAN Select mean statistic CALC3 DATA Request mean statistic Tnggenng Trigger models Explains the various components of the trigger models which con trol the triggering operations of the instrument Also explains how to configure the trig ger model from the front panel SCPI programming Includes the commands use
85. tests passed 0 1 CALC2 LIM1 test failed 1 0 CALC2 LIM2 test failed DISPlay FORM at and SYSTem 16 7 Bits 7 and 8 Measure Provides measurement status Bit8 Bit7 0 0 Voltage function selected 0 1 Current function selected 1 0 Resistance function selected 1 1 Charge function selected Bit 9 Zero Check Set to 1 when zero check is enabled Bit 10 Zero Correct Set to 1 when zero correct is enabled Example The ASCII data string in Figure 16 1 contains all three data elements The status value of 138 has a binary equivalent of 01001010 which indicates that bits B1 B3 and B7 are set Therefore the reading is 1 04056uA with null REL and the AVG filter enabled The read ing was taken 223 6299 seconds after the instrument was turned on C FORMat BORDer lt name gt Parameters NORMal Normal byte order for IEEE 754 binary format SWAPped Reverse byte order for IEEE 754 binary format For normal byte order the data format for each element is sent as follows Bytel Byte2 Byte3 Byte4 For reverse byte order data is sent as follows Byte4 Byte3 Byte2 Bytel The 0 header see Figure 16 2 is not affected by this command The header is always sent at the beginning of the data string for each measurement conversion The ASCII data format can only be sent in the normal byte order The SWAPped selection is ignored when the ASCII format is selected NOTE The SWAPped byte order must be used when transmitting binary
86. the sum of the two currents I Ip 10nA Obviously if Ip is a low level current then the 10nA leakage will corrupt the measurement Figure 4 3B shows the guarded version of the same circuit Notice that the only difference is that the connections to the electrometer are reversed Resistor Ry now represents the leakage from ammeter input HI to ammeter input LO and resistor Rg represents the leakage from amme ter input LO guard to test circuit common As previously mentioned the ammeter drops almost OV If the actual voltage drop across the ammeter is lt 2mV it then follows that there is a lt 2mV drop across R Therefore the current through R is lt 2pA lt 2mV 1GQ lt 2pA The current that is being measured by Model 6514 is the sum of the two currents I Ip lt 2pA The use of guarding reduced the leakage current from 10nA to lt 2pA Note that the 10nA leakage current Ig from ammeter input LO to test circuit common still exists but it is of no consequence since it is not measured by Model 6514 Amps M easurements 4 7 Figure 4 3 10V Floating current HI 6514 measurements I I 10nA lt hr LO v Wy R RL 10V _ ito gt iGa 10nA k d eo Z A Unguarded 10V 6514 k d Ik lt 2pA R 2mV R 2m _ nn 4 iGo 7 lt 2PA e Re f s 10V_ 10nA 1GQ 1GQ B Guarded 4 8 Amps Measurements SCPI programming Table 4 1 SCPI commands
87. the various commands are listed in Table F 2 Table F 2 Hexadecimal and decimal command codes Command Hex value Decimal value GTL 01 1 SDC 04 4 GET 08 8 LLO 11 17 DCL 14 20 SPE 18 24 SPD 19 25 LAG 20 3F 32 63 TAG 40 5F 64 95 SCG 60 7F 96 127 UNL 3F 63 UNT SF 95 EEE 488 Bus Overview F 11 Typical command sequences For the various multiline commands a specific bus sequence must take place to properly send the command In particular the correct listen address must be sent to the instrument before it will respond to addressed commands Table F 3 lists a typical bus sequence for sending the addressed multiline commands In this instance the SDC command is being sent to the instru ment UNL is generally sent as part of the sequence to ensure that no other active listeners are present Note that ATN is true for both the listen command and the SDC command byte itself Table F 3 Typical bus sequence Data bus Step Command ATN state ASCII Hex Decimal 1 UNL Set low 3F 63 2 LAG Stays low 2E 46 3 SDC Stays low EOT 04 4 4 Returns high Assumes primary address 14 Table F 4 gives a typical common command sequence In this instance ATN is true while the instrument is being addressed but it is set high while sending the common command string Table F 4 Typical addressed command sequence Data bus Step Command ATN state ASCII Hex Decimal 1 UNL Set low
88. to the equipment and within easy reach of the operator For maximum safety do not touch the product test cables or any other instruments while power is applied to the circuit under test ALWAYS remove power from the entire test system and discharge any capacitors before connecting or disconnecting 5 03 cables or jumpers installing or removing switching cards or making internal changes such as installing or removing jumpers Do not touch any object that could provide a current path to the common side of the circuit under test or power line earth ground Always make measurements with dry hands while standing on a dry insulated surface capable of withstanding the voltage being measured The instrument and accessories must be used in accordance with its specifications and operating instructions or the safety of the equipment may be impaired Do not exceed the maximum signal levels of the instruments and accessories as defined in the specifications and operating information and as shown on the instrument or test fixture panels or switching card When fuses are used in a product replace with same type and rating for continued protection against fire hazard Chassis connections must only be used as shield connections for measuring circuits NOT as safety earth ground connections If you are using a test fixture keep the lid closed while power is applied to the device under test Safe operation requires the use of a lid interlock Ifa
89. 0 00 eee eee ee cseeseeceeeaecaeeeaeceeeaeees 1 5 Rear panel SumMMaLy ssc c ccciccavside euciitieeviieraneasieecsees 1 8 POWEE UP iespschiseticietvies actin eet dane sias teens ued S 1 10 Line power CONNECTION eee eeeeeecseeeeeceecnaeceenseeerens 1 10 Line frequency selection eee eseeeteecnseceeeeseeeeees 1 10 POWeT UP SEQUENCE eeeceeeecsseceeeceneecesceeneeesneeceeceeeeenees 1 11 Display a s25 22h eyes e e ENa a EESE Ta 1 12 Status and error Messages eesseesereeeseeerrererrerrereersreerrreet 1 12 Default settings s s nesseneseessessesseserseeessteessetstssrsesessrsresreeeseenens 1 12 SCPI progtamminE onesie o ernes no EE Rn E EERS 1 15 Measurement Concepts Measurement overview ceecceecsseecssceecsscecessueeceesececsseeeesseeeenees 2 2 Performance considerations eseseeesseresseresrsreserrstrrerrererrereses 2 2 Warm Up Period ou eee isser tssgsrarrin niie i 2 2 PULO ZERO M E AE 2 2 Connection fundamentals ssseeeeeeeeseeeeeeiereeereerersererrsrsrereerene 2 3 Input C nNeCtOT seasic secteeisseccasssessuseaseessacscaaesesdenssnetbaseseveeons 2 3 Low noise input cables 0 0 eee cece cseeseceeceseeeeeeseeeneeees 2 5 Basic connections tO DUT oo eee eeeeseceeceeeceeeeeeeeneeees 2 6 Test DX CULE ui sci esigere Erene erderan EEE aE E EE EE 2 9 Input ProtectiONy vss sictacsastissessccdiseeAuiasenuldanawrine 2 11 Floating measurements 0 eee ceeeeeseceeeeeeeeeeeceeeeesaeeenees 2 11 Zero che
90. 0 0000V 100MQ 2uA gt 15 sec Nominal resistance values 2 Nominal currents Calculate actual currents from calibrator voltage and actual standard resistor value I V R Calibrate zero posi tive full scale and negative full scale for each range Triax cap used for zero cal points 3 Allow calibration signal to settle for indicated time before calibrating each point 19 14 Calibration Coulombs calibration 1 Connect the voltage calibrator and Model 5156 Calibration Standard to Model 6514 INPUT jack as shown in Figure 19 4 Initially make connections to the InF capacitor Also be sure to connect the link between SHIELD and CHASSIS Figure19 4 Connec tions for coulombs DC Voltage Calibrator Model 6514 Electrometer eee cmo oce a OO0OO0OO0OO0OOOO0OO0OO O 26 O00 000 DD 000 000 000 OO 2 LD lJo00 000 0D O00 Oco OO Connect Cable Shield to O utput LO Low noise Coax Cable Note Connect voltage calibrator to appropriate capacitor Be sure shield LO to chassis link is connected Charge Filter Adapter 1062 ice 100nF 100M Q Triax Cable Model 5156 Calibration Standard 2 Select Model 6514 coulombs function by pressing the Q key and set the calibrator to output volts Using the GRD key disable Model 6514 guard mode 4 Select Model 6514 20nC range
91. 000V 199 877 to 200 123V Model 6514 range Calibrator voltage 18 12 Performance Verification Amps measurement accuracy Follow the steps below to verify that Model 6514 amps function measurement accuracy is within specified limits The test involves applying accurate DC currents and then verifying that Model 6514 current readings are within required limits 20uA 20mA range accuracy 1 Connect the current calibrator to Model 6514 INPUT jack as shown in Figure 18 2 Use the appropriate triax to BNC low noise coaxial cable and BNC to dual banana plug adapters where shown Figure 18 2 Connections for 20pA 20mA range verification Soe z OO0O0O00 0000 0 O00 O00 OO0O00 ooo ool OO ooo OOO OO O00 OC OO e Low noise Coax BNC Cable Model 6514 Electrometer BN C to dual Banana Plug Adapter Connect Cable Shield to Output LO DC Current Calibrator 2 Select Model 6514 DC amps function with the I key and set the calibrator to output DC current Set Model 6514 to the 20uA range using the up or down RANGE key With zero check enabled zero correct Model 6514 then disable zero check Set the calibrator current to 0 0000uUA and make sure the output is turned on Enable Model 6514 REL mode Leave REL enabled for the remainder of the test Verify current measurement accuracy for each of the currents listed in Table 18 3 For each test point e Select t
92. 02 1 200V 1mV 0 06 3 0 002 1 Note 1 When properly zeroed 5 digit Rate Slow 100ms integration time NMRR 60dB on 2V 20V gt 55dB on 200V at 50Hz or 60Hz 0 1 CMRR gt 120dB at DC 50Hz or 60Hz INPUT IMPEDANCE gt 200TQ in parallel with 20pE lt 2pF guarded 10MQ with zero check on SMALL SIGNAL BANDWIDTH AT PREAMP OUTPUT Typically 100kHz 3dB AMPS ACCURACY TEMPERATURE 1 Year COEFFICIENT 5 DIGIT 18 28 C 0 18 C amp 28 50 C RANGE RESOLUTION Yordg counts Yordg counts C 20 pA 100 aA 1 30 0 1 5 200 pA 1 fA2 1 38 0 1 1 2 nA 10 fA 0 2 30 0l 2 20 nA 100 fA 0 2 5 0 03 1 200 nA 1pA 0 2 5 0 03 1 2 pA 10 pA 0 1 10 0 005 2 20 pA 100 pA 0l 5 0 005 1 200 pA 1nA 014 5 0 005 1 2mA 10nA 0 1 10 0 008 2 20mA 100 nA 014 5 0 008 1 Notes 1 When properly zeroed 5 digit Rate Slow 100ms integration time 2 aA 10718a fA 10715A INPUT BIAS CURRENT lt 3fA at Tcay user adjustable Temperature coefficient 0 5fA C INPUT BIAS CURRENT NOISE lt 750aA p p capped input 0 1Hz to 10Hz band width damping on Digital filter 40 readings INPUT VOLTAGE BURDEN at Tcay 1 C user adjustable lt 20pV on 20pA 2nA 20nA 2A 201A ranges lt 100pV on 200pA 200nA 200A ranges lt 2mV on 2mA range lt 4mV on 20mA range TEMPERATURE COEFFICIENT OF INPUT VOLTAGE BURDEN lt 10uV C on pA nA yA ranges PREAMP SETTLING TIME to 10 of final value 2 5s typical on pA
93. 05nA 200nA 20V 100MQ 200 000nA V 199 595 to 200 405nA 2uA 200V 100MQ 2 00000u A V 1 99790 to 2 00210uA l Nominal resistance values shown Use actual characterized value for calculations 2 Calculate actual calibrator voltage as follows V IR where I is desired applied current and R is actual standard resistance value Performance Verification 18 15 Ohms measurement accuracy Follow the steps below to verify that Model 6514 ohms function measurement accuracy is within specified limits This procedure involves applying accurate resistances from a resistance calibrator or standard and then verifying that Model 6514 resistance measurements are within required limits WARNING Withtheohmsfunction selected the M odel 6514 can output an open circuit voltage up to 250V Place the unit in zero check when leads are not con nected 2kQ 20M Q range accuracy 1 Connect the resistance calibrator to Model 6514 INPUT jack as shown in Figure 18 4 Figure 18 4 Connections for ohms verification 2kQ 20MQ ranges Low noise Coax BNC Cable Input Calibrator Output Model 6514 Electrometer BNC to dual Resistance Calibrator Banana Plug Adapter Connect Cable Shield to Output LO 2 Select Model 6514 ohms function by pressing the Q key and set the calibrator to the resistance function With zero check enabled zero correct the instrument then disable zero check 4 Output OQ from th
94. 0k 20nC 20V R4 200V 2nA 2MQ 200nC 200V R5 200V 20nA 20M9 2uC 200V R6 200V 200nA 200MQ 20uC 200V R7 200V 2uA 2GQ 20uC 200V R8 200V 20uA 20GQ 20uC 200V R9 200V 200uA 200GQ 20uC 200V R10 200V 2mA 200GQ 20uC 200V R11 200V 20mA 200GQ 20uC 200V R12 Cancel Auto range for all functions Trigger Mode TO Continuous triggered by talk Tl One shot triggered by talk T2 Continuous triggered by GET T3 One shot triggered by GET T4 Continuous triggered by X TS One shot triggered by X T6 Continuous triggered by External Trigger T7 One shot triggered by External Trigger Status Word U0 Return status word FRRCZNTOBGOQMMKY Y D YY LFCR CRLF 0 LF 0 CR 00 None Ul Send error conditions U2 Send data conditions E U3 Buffer size and readings stored F Execute X Execute other device dependent commands F Table D 1 cont Device dependent command summary DDC Emulation Commands Mode Command _ Description Note Terminator YO LFCR line feed carriage return D Y1 CRLF carriage return line feed Y2 LF line feed Y3 CR carriage return Y4 None Zero Correct ZO Zero Correct disabled Z1 Zero Correct enabled A The hit key command Hn is not used by the SYSTem KEY command see Section 16 for B The buffer size command In is not used by Models 6512 617 and 617 HIQ The hit command is similar to the SCPI details he Models 6512 617 and 617 HIQ The buffer size command is similar to the SCPI TRACe P
95. 1 BO Enable Register Decimal 128 _ 32 16 8 4 1 Weights 27 2 24 23 2 2 OSB Operation Summary Bit amp Logical AND MSS Master Summary Status OR Logical OR RQS Request for Service ESB Event Summary Bit MAV Message Available QSB Questionable Summary Bit EAV Error Available MSB Measurement Summary Bit Status byte register The summary messages from the status registers and queues are used to set or clear the appro priate bits BO B2 B3 B4 B5 and B7 of the status byte register These summary bits do not latch and their states 0 or 1 are solely dependent on the summary messages 0 or 1 For exam ple if the standard event register is read its register will clear As a result its summary message will reset to 0 which in turn will reset the ESB bit in the status byte register 13 8 Status Structure The bits of the status byte register are described as follows Bit BO measurement status MSB Set summary bit indicates that an enabled mea surement event has occurred Bit B1 Not used Bit B2 error available E AV Set summary bit indicates that an error or status mes sage is present in the error queue Bit B3 questionable summary bit QSB Set summary bit indicates that an enabled questionable event has occurred Bit B4 message available M AV Set summary bit indicates that a response message is present in the output queue Bit B
96. 1 2 outputs a trigger pulse Since the instrument is pro grammed to scan 10 channels operation loops back to point B where it waits for an input trigger With Model 6514 at point A the output trigger pulse from Model 7001 2 triggers a mea surement of DUT 1 point E After the measurement is complete Model 6514 outputs a trigger pulse and then loops back to point A where it waits for another input trigger The trigger applied to Model 7001 2 from Model 6514 closes the next channel in the scan which then triggers Model 6514 to measure that DUT This process continues until all 10 chan nels are scanned and measured 10 Limit Tests Limit testing Explains the basic Limit 1 and Limit 2 testing operations Binning Explains how to use a component handler to perform binning operations Front panel operation Explains how to configure and run tests from the front panel SCPI programming Covers the SCPI commands for remote operation 10 2 Limit Tests Limit testing As shown in Figure 10 1 there are two limit tests that can be performed on a DUT Limit 1 is used as the wide pass band and Limit 2 is used as the narrow pass band It is up to the user to specify limits that conform to this pass band relationship Figure 10 1 Limit tests Figure 10 2 Limit tests example 2V 2V te Fail Pass Fail LO Limit HI Limit 1V 1V Fail Pass Fail LO Limit HI Limit LO HI w Fail Pass Fail
97. 18 6 External feedback 11 11 External feedback procedure 11 13 External trigger example 9 12 External triggering 9 11 External voltage source 5 6 Filters 6 8 Floating measurements 2 11 FORMat subsystem 16 4 Front and rear panel familiarization 1 5 Front panel 2 17 Front panel GPIB operation 12 10 Front panel operation 10 10 Front panel summary 1 5 Front panel tests 20 4 General bus commands 12 8 General information 1 2 General Measurement Considerations C 1 General notes 17 2 Generating SRQ on buffer full E 4 Getting Started 1 1 GPIB bus connections 12 5 GPIB bus standards 12 5 GPIB operation and reference 12 5 Ground loops C 2 Guarding 3 2 Guarding input cable 3 12 Handshake lines F 6 High impedance measurement techniques 4 5 Humidity C 4 Idle and initiate 9 4 IEEE command groups F 12 IEEE 488 and SCPI Conformance Information G 1 IEEE 488 Bus Overview F 1 Input bias current 4 9 5 6 Input bias current and offset voltage calibration 2 17 18 9 19 7 Input bias current calibration 18 9 Input cable leakage and capacitance 3 3 Input capacitance settling time 3 10 Input connector 2 3 Input protection 2 11 Input trigger requirements 9 11 Inspection 1 2 Interface function codes F 13 Interface selection and configuration procedures 12 2 Interfaces 12 2 Introduction 18 2 19 2 20 2 F 2 G 2 H 2 KEY test 20 4 Languages 12 2 Light C 4 Limit test configuration 10 10 Limit testi
98. 1V CALC2 NULL STAT ON Enable Rel CALC2 FEED SENS Rel input signal INIT Trigger reading s CALC2 DATA Request Rel ed reading mX b and percent This math operation manipulates normal display readings X mathematically according to the following calculation Y mX b where X is the normal display reading m and b are user entered constants for scale factor and offset Y is the displayed result To configure and control the mX b calculation perform the following steps 1 Press SHIFT and then MX B to display the present scale factor M 1 0000000 factory default 2 Key ina scale factor value The lt and p keys control cursor position and the A and w range keys increment and decrement the digit value To change range place the cursor Relative mX b and Percent 7 5 on the range symbol and use the a and y keys With the cursor on the polarity sign the A and keys toggle polarity NOTE Range symbols are defined in Table 7 1 3 Press ENTER to enter the M value and display the offset B value B 00 000000 P factory default 4 Key in the offset value 5 Press ENTER to enter the B value and display the three character UNITS designator UNITS MXB factory default 6 Use the lt and cursor keys and the a and w keys if you wish to change the units des ignator Each character can be any letter in the alphabet A through Z 7 Press ENTER The MATH annunciator will turn on
99. 2 Red H1 Connections for unguarded volts and ohms o M etal N oise Shield T Metal Safety Shield Safety 237 ALG 2 Earth Cable Ground we WARNIN Gino INTERNAL OPERATOR SERVICABLE PARTS SERVICE BY QUALIFIED PERSONNEL ONLY KEITHLEY 48n IEEE 488 PREAMP OUT 2V ANALOG COMMON CHASSIS CHANGE IEEE ADDRESS P 250V PK OUTPUT WITH FRONT PANEL MENU we omo Gam g INPUT 250V PK DIGITAL I O TRIGGER LINK RS232 LINE RATING INPUT riae A 50 60Hz PREAMP m VA MAX ore 10K OUT Line 2V ANALOG er OUTPUT Pe 100 VAC faa Q GUARD INPUT 120 VAC TrpRoGRaMMaBte sismat 220 vac TIS INTERNAL 6B NA CAUTION FOR CONTINUED PROTECTION AGAINST FIRE HAZARD REPLACE FUSE WITH SAME TYPE AND RATING 6514 Rear Panel GRD Disabled 3 6 Volts and Ohms Measurements Guarded connections Connections for guarded volts and ohms measurements are shown in Figure 3 3 The driven guard GRD must be enabled for these measurements WARNING Withan open input up to 250V peak may be present on the guard terminals while in Volts or Ohms To prevent this make sure zero check is enabled whenever the input is open Figure3 3 0 Connections for Le Metal Safety Shield Metal Guard Plate guarded volts and P Safety ohms Earth Red H1 Ground LO 237 ALG 2 Cable Chassis WARMIN G no mT Yy PREAMP OUT 2V ANALOG COMMON TS SERVICE BY QUALIFIED PERSONNEL ONLY
100. 5 event summary bit E SB Set summary bit indicates that an enabled standard event has occurred Bit B6 request service RQS master summary status MSS Set bit indicates that an enabled summary bit of the status byte register is set Bit B7 operation summary OSB Set summary bit indicates that an enabled oper ation event has occurred Depending on how it is used bit B6 of the status byte register is either the request for service RQS bit or the master summary status MSS bit When using the serial poll sequence of Model 6514 to obtain the status byte a k a serial poll byte B6 is the RQS bit See serial polling and SRQ for details on using the serial poll sequence When using the STB command see Table 13 3 to read the status byte B6 is the MSS bit Service request enable register The generation of a service request is controlled by the service request enable register This register is programmed by you and is used to enable or disable the setting of bit B6 RQS MSS by the status summary message bits BO B2 B3 B4 B5 and B7 of the status byte register As shown in Figure 13 3 the summary bits are logically ANDed amp with the corresponding enable bits of the service request enable register When a set 1 summary bit is ANDed with an enabled 1 bit of the enable register the logic 1 output is applied to the input of the OR gate and there fore sets the MSS RQS bit in the status byte regist
101. 6 vV 10 5 50Hz NPLCycles Query NPLC vV RANGe Configure measurement range Sec 6 V UPPer lt NRf gt Select range 21e 6 to 21e 6 coulombs 2 le 6 v UPPer Query range value vV AUTO lt b gt Enable or disable autorange see Note vV 17 8 SCPI Reference Tables Table 17 4 cont SENSe command summary Default Command Description parameter Ref SCPI LGRoup lt name gt Specify autorange limit HIGH or LOW HIGH LGRoup Query upper limit for autorange AUTO Query state of autorange V ADIScharge Path for auto discharge Sec 5 LEVel lt NRf gt Set auto discharge level 21e 6 to 21e 6 2e 6 LEVel Query auto discharge level STATe lt b gt Enable or disable auto discharge OFF STATe Query state of auto discharge AVERage Path to control the Digital Filter Sec 6 TCONtrol lt name gt Select filter control MOVing or REPeat REP TCONtrol Query filter control COUNt lt n gt Specify filter count 2 to 100 10 COUNt Query filter count STATe lt b gt Enable or disable digital filter OFF STATe Query state of digital filter MEDian Path to control median filter Sec 6 RANK lt NRf gt Specify n for rank 1 to 5 rank 2n 1 1 RANK Query rank STATe lt b gt Enable or disable median filter OFF STATe Query state of median filter Note RST default is ON and SYSTem PRESet default is OFF
102. 60 LFRequency Read present line frequency setting Getting Started 1 11 Power up sequence The following power up sequence occurs when the Model 6514 is turned on 1 The Model 6514 performs self tests on its EPROM and RAM with all digits and annun ciators turned on If a failure is detected the instrument momentarily displays an error message and the ERR annunciator turns on Error messages are listed in Appendix B NOTE Ifa problem develops while the instrument is under warranty return it to Keithley Instruments Inc for repair 2 Ifthe instrument passes the self tests the firmware revision levels are displayed For example 6514 REV A01 3 The detected line frequency is then displayed For example FREQ 60Hz 4 Lastly information on the selected remote interface is displayed a GPIB If the GPIB is the selected interface the instrument will display the selected language SCPI or DDC and primary address Examples SCPI ADDR 14 DDC ADDR 14 b RS 232 If RS 2372 is the selected interface the instrument will display the baud rate setting For example RS 232 9600b 1 12 Getting Started Display Readings can be displayed in engineering units or scientific notation see Units in Section 6 for details Annunciators indicate various states of operation See Front Panel Summary presented earlier in this section for a complete listing of display annunciators NOTE The Display and
103. 8 Charge calculations 18 7 Clearing registers and queues 13 4 Command F 10 Command codes F 10 Common Commands 14 1 F 10 Component handler interface 10 6 Component handler types 10 7 Condition registers 13 15 Connection fundamentals 2 3 Contact information 1 2 Controlling the Model 6514 via the RS 232 COM2 port E 7 Coulombs calibration 19 14 Coulombs measurement accuracy 18 18 Coulombs measurement considerations 5 6 Coulombs measurement procedure 5 3 Coulombs Measurements 5 1 Current and charge calculations 19 6 Current calculations 18 7 Damping 4 4 Data lines F 5 Data transfer connections H 2 DDC Emulation Commands D 1 DDC language D 2 Default settings 1 12 Digital 6 9 Digital filter 6 9 Digital I O port 11 2 Digital I O Analog Outputs and External Feedback 11 1 Digital output clear pattern 10 8 Digits 6 4 Diode leakage current 4 13 DISP test 20 4 Display 1 12 DISPlay subsystem 16 2 DISPlay FORMat and SYSTem 16 1 Displaying calibration dates 19 19 Displaying the calibration count 19 20 Electrochemical effects C 4 Electromagnetic Interference EMI C 5 Electrometer input circuitry 11 11 Electrostatic interference C 4 Entering calibration dates and saving calibration 19 18 Environmental conditions 18 3 19 2 Error messages 12 19 Error queue 13 19 Event enable registers 13 17 Event registers 13 16 Example program H 3 Example Programs E 1 Example reading limits calculation
104. ASure While operating within the trigger model not in idle most commands will not be executed until the instrument completes all of its programmed operations and returns to the idle state The IFC SDC and DCL commands can be executed under any circumstance while operating within the trigger model They will abort any other command or query The following commands can be executed while operating within the trigger model except when a READ or MEASure is being processed e ABORt e SYSTem PRESet e TRG or GET e RST e RCL lt NRf gt NOTE _ For fastest response use SDC or DCL to return to idle see Section 12 for details on general bus commands Trigger model operation Once the instrument is taken out of idle operation proceeds through the trigger model to per form a measurement measure action NOTE The following discussion focuses on the front panel trigger model Figure 9 1 How ever equivalent SCPI commands are included where appropriate Event detectors and control sources A control source holds up operation until the programmed event occurs and is detected Note that there are two detector bypasses A bypass around a detector is only enabled if the appropri Triggering 9 5 ate TLink control source is selected See TLink control source Arm In and Trigger In as fol lows for details Arm In source The Arm In control sources are explained as follows Immediate ARM SOURce IMMediate Event detec
105. AXimum When the DEFault parameter is used the instrument is programmed to the RST default value When the MINimum parameter is used the instrument is programmed to the lowest allowable value When the MAXimum parameter is used the instrument is programmed to the largest allowable value ARM TIMer 0 1 Sets timer to 100 msec ARM TIMer DEFault Sets timer to 0 1 sec ARM TIMer MINimum Sets timer to 1 msec ARM TIMer MAXimum Sets timer to 999999999 sec e Angle brackets lt gt Used to denote a parameter type Do not include the brackets in the program message DISPlay ENABle lt b gt The lt b gt indicates that a Boolean type parameter is required Thus to enable the display you must send the command with the ON or 1 parameter as follows DISPlay ENABle ON or 1 Query commands The query command requests the presently programmed status It is identified by the question mark at the end of the fundamental form of the command Most commands have a query form ARM TIMer Queries the timer interval Most commands that require a numeric parameter lt n gt can also use the DEFault MINimum and MAXimum parameters for the query form These query forms are used to determine the RST default value and the upper and lower limits for the fundamental command ARM TIMer DEFault Queries the RST default value ARM TIMer MINimum Queries the lowest allowable value ARM TIMer MAXimum Queries the largest allowable val
106. B No effect On at factory No effect On at factory Address No effect 14 at factory No effect 14 at factory Language No effect SCPI at factory No effect SCPI at factory 1 14 Getting Started Table 1 2 cont Default settings Setting Factory GPIB Limit Tests Limit 1 and Limit 2 Disabled Disabled HI and LO Values 1 1 1 1 Digital Fail Output Patterns 15 15 Digital Output Pass Pattern 15 15 Auto Clear Off Off Delay 0 00010 sec 0 00010 sec Output Clear Pattern 15 15 Line 4 Mode End of Test End of Test Median Filter Off Off Rank 1 1 MX B Disabled Disabled M Value 1 0 1 0 B Value 0 0 0 0 Units MXB MXB Percent Disabled Disabled Reference 1 0 1 0 Range 20V Auto Rate Slow Slow NPLC 6 0 60Hz or 5 0 50Hz 6 0 60Hz or 5 0 50Hz Rel Off Off Rel Value VAL 0 0 0 0 RS 232 No effect Off at factory No effect Off at factory All Settings No effect No effect Trigger Layer CONF TRIG Trig In Source Event IMM IMM Trigger Count 1 1 Trigger Delay 0 0 Input Trigger Link Line 1 1 Source Bypass NEVER NEVER Output Trigger Link Line 2 2 Units No effect No effect V Drop Disabled Disabled Zero Check Enabled Enabled Zero Correct Disabled Disabled Getting Started 1 15 SCPI programming SCPI programming information is integrated with front panel operation throughout this man ual SCPI commands are listed in tables and additional informati
107. BNC to double banana plug Fluke 5700A Fluke 5450A Keithley Model 5156 Keithley 7024 3 Keithley 4801 Keithley 237 ALG 2 Keithley 7078 TRX BNC Keithley CAP 31 Pomona 1269 I 90 day 23 5 C full range accuracy specifications shown Jaaa eRe Eia 23 3 C accuracy of characterization 3 Short red and black clips to make triax short DC voltage 2V 7ppm 20V S5ppm 200V 7ppm DC current 20uA 550ppm 200uUA 100ppm 2mA 55ppm 20mA 55ppm Nominal resistance 1 9kQ 8ppm 1 9MQ 11 5ppm Nominal resistance 2 100MQ 200ppm 1GQ 300ppm 10GQ 400ppm 100GQ2 500ppm Nominal capacitance 2 InF 1 000ppm 100nF 1 000ppm Calibration 19 5 Calibration errors Model 6514 checks for errors after each calibration step minimizing the possibility that improper calibration may occur due to operator error If an error is detected during calibration the instrument will display an appropriate error message The unit will then prompt you to repeat the calibration step that caused the error Calibration menu You can access the calibration menu by pressing SHIFT then CAL The various selections are summarized in Table 19 2 Use the up or down RANGE key to scroll through these selections Table 19 2 Calibration menu Menu item Description RUN Calibrates present function and range COUNT Displays calibration count IOFFSET Performs input bias current calibration VOFFSET Performs offset voltage
108. Checking changing R S 232 settings Press SHIFT and then RS 2372 to access the RS 232 menu and perform the following steps 1 2 Use the A or y key to display the RS 232 settings If these settings are correct press EXIT to exit the menu Otherwise continue on to change one or more settings Use the A or y key to display the baud rate BAUD To retain this baud rate press ENTER To change the baud rate a Press the lt or key to move the cursor over to the baud rate value b Use the or y key to display the desired baud rate 300 to 57 6k c Press ENTER The data bits setting is then displayed To retain the displayed data bits setting BITS press ENTER To change the data bits setting a Press the lt or p key to move the cursor over to the data bits value b Use the or w key to display the desired number of data bits 8 or 7 c Press ENTER The parity setting is then displayed To retain the displayed parity setting PARITY press ENTER To change the parity setting a Press lt or p to move the cursor over to the parity setting b Use A or w to display the desired parity NONE ODD or EVEN c Press ENTER The terminator is then displayed To retain the displayed terminator TX TERM press ENTER To change the terminator a Press lt or p to move the cursor over to the terminator setting b Use A or w to display the desired terminator LFCR CR CRLF or LF c Press ENTER The flow control s
109. EVER the source bypass e ARM OUT Configure the output trigger LINE Select the output trigger link line 1 to 6 EVENT Enable ON or disable OFF the trigger layer done output trigger e COUNT Seta finite FIN arm count 1 to 2500 or select infinite INF arm count NOTE Input trigger and output trigger cannot share the same Trigger Link line Defaults set line 1 as the input and line 2 as the output Trigger layer configuration menu The configuration menu for the trigger layer is struc tured as follows Bullets denote the main items of the menu To access the menu press SHIFT and then CONF TRIG e TRIG IN Select the Trig In control source IMM Immediate or TLINK After selecting TLINK select the input trigger link line 1 to 6 You will then be prompted to enable ONCE or disable NEVER the source bypass 9 8 Triggering e TRIG OUT Configure output triggers LINE Select the output trigger link line 1 to 6 VMC Enable ON or disable OFF the VMC voltmeter complete output trigger e DELAY Configure the trigger delay of the trigger layer MAN Manually set the delay 0 to 999 9998 seconds AUTO Selects auto delay The delay is set according to function range see Table 9 1 e COUNT Seta finite FIN trigger count 1 to 2500 or select infinite INF trigger count NOTE Input trigger and output trigger cannot share the same trigger link line Defaults set
110. Figure 2 4 shows typical shielding for unguarded measure ments A noise shield is used to prevent unwanted signals from being induced on the electrom eter input Measurements that may benefit from effective shielding include unguarded volts and ohms amps below 1uA and low level coulombs Typically the noise shield is connected to electrometer input LO However better noise per formance may be achieved by connecting the noise shield to both input LO and chassis ground Electrometer LO can be connected to chassis ground by installing the ground link between the COMMON and CHASSIS binding posts A safety shield is required whenever a hazardous voltage gt 30V is present on the noise shield or when the test circuit DUT is floated above earth ground at a hazardous voltage level see Floating Measurements Connections for the safety shield is shown in Figure 2 4B The metal safety shield must completely surround the noise shield or floating test circuit and it must be connected to safety earth ground using 18 AWG or larger wire HI De M etal N oise Shield a INPUT 250V PK A Noise Shield HI ky ey Metal N oise Shield OSE ee Chassis Metal Safety Shield Gi Goud i p INPUT be Safe 250V PK Jo faa Path Ground B Safety Shield 2 8 Measurement Concepts Guarded connections The basic guarded connections for volts and ohms are shown in Figure 2
111. K The limitations in this equation center on the factors Ip m and RB I is the extrapolated cur rent for Vo An empirical proportional constant m accounts for the different character current conduction recombination and diffusion mechanisms within the junction typically varying between 1 and 2 Finally RB constitutes the ohmic bulk resistance of the diode junction mate rial Io and RB limit the usefulness of the junction diode at low and high currents respectively The factor m introduces non linearity s between those two extremes Because of these limita tions most diodes have a limited range of logarithmic behavior A solution to these constraints is to use a transistor configured as a transdiode in the feed back path as shown in Figure 11 9 Analyzing the transistor in this configuration leads to the relationship V kT q In W p In hpp 1 hpp where hpg is the current gain of the transistor Figure 11 9 Transdiode logarithmic current configuration Current gt Input gt Model 6514 Input 1oMe gt gt r NVV 5 LO lt 1Q I COM i NNN Q1 i Preamp p Out Chassis gt VS To Ranging Amplifier From this equation proper selection of Q1 would require a device with high current gain hpg which is maintained over a wide range of emitter currents Suitable devices for this appli cation include Analog Devices AD8 12 and Precision Monolithics MAT 01
112. KEITHLEY Model 65 14 System Electrometer Instruction Manual A GREATER MEASURE OF CONFIDENCE WARRANTY Keithley Instruments Inc warrants this product to be free from defects in material and workmanship for a period of year from date of shipment Keithley Instruments Inc warrants the following items for 90 days from the date of shipment probes cables rechargeable batteries diskettes and documentation During the warranty period we will at our option either repair or replace any product that proves to be defective To exercise this warranty write or call your local Keithley representative or contact Keithley headquarters in Cleveland Ohio You will be given prompt assistance and return instructions Send the product transportation prepaid to the indicated service facility Repairs will be made and the product returned transportation prepaid Repaired or replaced products are warranted for the balance of the original warranty period or at least 90 days LIMITATION OF WARRANTY This warranty does not apply to defects resulting from product modification without Keithley s express written consent or misuse of any product or part This warranty also does not apply to fuses software non rechargeable batteries damage from battery leakage or problems arising from normal wear or failure to follow instructions THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED INCLUD ING ANY IMPLIED WARRANTY OF MERCHAN
113. LO 2 Select Model 6514 volts function by pressing the V key and set the calibrator to output DC volts 3 Select Model 6514 2V range and make sure the calibrator output is turned on 4 Press SHIFT then CAL to access the calibration menu The unit will display the following CAL RUN 5 Press ENTER The unit will prompt for the zero calibration point 2V ZERO 6 Connect a triax short to the INPUT jack and then press ENTER 7 The unit will prompt for the 2V cal point 2V CAL Calibration 19 9 8 Press ENTER The unit will display the following for the positive full scale calibration voltage 2 000000 DCV 9 Set the calibrator output voltage to 2 000000V then adjust Model 6514 display to agree with that value NOTE _ If your calibrator cannot source the recommended calibration values use the closest values then set Model 6514 display to agree with the calibrator signal levels Use the up and down RANGE keys to select the digit value and use the left and right arrow keys to choose the digit position 10 Press ENTER The unit will prompt for the negative full scale calibration point 2V CAL 11 Press ENTER The Model 6514 will prompt for the negative full scale calibration volt age 2 000000 VDC 12 Set the calibrator output voltage to 2 000000V then adjust the display to agree with the calibrator voltage Press ENTER to complete calibration of the present range 13 Press EXIT to return to normal display 14 Re
114. LT RANG AUTO lt b gt CURR RANG AUTO lt b gt RES RANG AUTO lt b gt CHAR RANG AUTO lt b gt CURR NPLC lt n gt RES NPLC lt n gt CHAR NPLC lt n gt VOLT NPLC lt n gt RES NPLC lt n gt CHAR NPLC lt n gt VOLT NPLC lt n gt CURR NPLC lt n gt CHAR NPLC lt n gt VOLT NPLC lt n gt CURR NPLC lt n gt RES NPLC lt n gt TRAC FEED CONT lt name gt TRAC FEED CONT lt name gt TRAC CLE CHAR RANG UPP lt n gt Acquired value Acquired value OFF OFF OFF OFF Volts PLC value Volts PLC value Volts PLC value Amps PLC value Amps PLC value Amps PLC value Ohms PLC value Ohms PLC value Ohms PLC value Charge PLC value Charge PLC value Charge PLC value NEV NEV If autorange ON then 2uC if old range lt 2nC and LRG UPPer or 200nC if old range gt 200nC and LGR LOWer H Calibraton O ptons H 2 Calibration Options This appendix contains information on reading Model 5156 Electrometer Calibration Stan dard values as well as a summary of Model 6514 remote calibration commands See Section 19 for complete calibration information Reading calibration standard values Instead of manually computing calibration currents and charge values you can read out Model 5156 Electrometer Calibration standard values via remote then use a computer to calculate those values Data transfer connections Figure H 1 shows data transfer connections Connect the Model 6514 DIGITAL I O connec
115. Mer command to set the timer interval D DiRection lt name gt The source bypass can only be used if the TLINk control source is selected E ILINe lt name gt and OLINe lt name gt Input trigger and output trigger cannot share the same trigger link line Defaults set line 1 as the input and line 2 as the output F TRIGger CLEar When this action command is sent any pending latched input triggers are cleared immedi ately When the Model 6514 is being latched by another instrument it may inadvertently receive and latch input triggers that do not get executed These pending triggers could adversely affect subsequent operation When using external triggering it is recommended that TRIGger CLEar be sent after sending the ABORt command and at the beginning of a program before sending an initiate command See INITiate command Programming example The following command sequence will trigger and return 10 readings RST ARM SOURce IMMediate ARM COUNt 1 Return 6514 to RST defaults Set arm control source Immediate Set arm count to 1 4 4 4 4 TRIGger SOURce IMMediate Set trigger control source Immediate TRIGger COUNt 10 Set trigger count to 10 READ Trigger and return 10 readings Triggering 9 11 External triggering Input and output triggers are received and sent via the rear panel TRIGGER LINK connector The trigger link has six lines At the factory line 2 is selected for output trigg
116. N 6 With N displayed press ENTER Input bias current and offset voltage calibration Before performing the remaining calibration steps perform input bias current and offset volt age calibration as outlined below O ffset voltage calibration 1 From the calibration menu use the up or down RANGE key to display the following CAL VOFFSET 2 Press ENTER The instrument will prompt for a short INPUT SHORT 19 8 Calibration 3 Connect the triax short triax cable with red and black alligator clips connected together to the rear panel INPUT jack 4 Press ENTER to complete offset voltage calibration Input bias current calibration 1 From the calibration menu use the down RANGE key to display the following CAL IOFFSET 2 Press ENTER The instrument will prompt for an open input INPUT CAP Connect the triax shielding cap to the rear panel INPUT jack 4 Press ENTER to complete input bias current calibration Volts calibration 1 Connect the voltage calibrator to Model 6514 INPUT jack as shown in Figure 19 1 Be sure to use the low noise coaxial cable and appropriate adapters as shown ya Figure 19 1 Connections for volts calibration Low noise Coax BNC Cable BOOD oOo O GG O GI O00 ODG GOGO Calibrator 7 000 00 Output Ooo og oc o0 Model 6514 Electrometer BN C to dual DC Voltage Calibrator Banana Plug Adapter Connect Cable Shield to Output
117. OINts command see Section 8 for details C The moving filter cannot be selected from the DDC language D For the Models 6512 617 and 617 HIQ the terminator commands Y to set the terminator are different from the Y commands used by the Models 6512 617 and 617 HIQ Also note that the YY response to the UO command is different D 5 E For the Model 6514 the Buffer Full bit in the U2X status word does not get cleared until either the buffer is resized or buffer stor age is reactivated Note that requesting a buffer reading does not clear the U2 Buffer Full bit F The U3 status command is not used by the Models 6512 617 and 617 HIQ The response message indicates the buffer size In and the actual number of readings stored in the buffer Example Programs Example Programs Programming examples All examples assume QuickBASIC version 4 5 or higher and a CEC TEEE 488 interface card with CEC driver version 2 11 or higher with the Model 6514 at address 14 on the IEEE 488 bus Changing function and range The Model 6514 has independent range control for each of its four measurement functions This means for example that autorange can be turned on for Volts while leaving it off for the rest of the functions Another difference is in the parameter for the range command The parameter value for the RANGe command is given as the maximum value to measure The instrument interprets this parameter and goes to
118. Quire Use input signal as Rel value OFFSet lt NRf gt Specify Rel value 9 999999e20 to 0 0 vV 9 999999e20 OFFSet Query Rel value vV STATe lt b gt Enable or disable Rel OFF vV STATe Query state of Rel V DATA Return all CALC2 readings triggered by INITiate vV LATest Return only the last latest reading CALCulate3 Path to configure and control CALC3 calculations Sec8 Vv on buffer data FORMat lt name gt Select buffer statistic MEAN SDEViation MEAN v Maximum MINimum or PKPK FORMat Query selected statistic vV DATA Read the selected buffer statistic vV SOU Rce2 lt N DN gt and lt NRf gt parameters lt NDN gt Bxxxx Binary format each x 1 or 0 Hx Hexadecimal format x 0 to F Qxx Octal format x 0 to 17 lt NRf gt 0to15 Decimal format SCPI Reference Tables 17 5 Table 17 2 DISPlay command summary Default Command Description parameter Ref SCPI DISPlay Sec 16 DIGits lt n gt Set display resolution 4 to 7 6 Sec 6 DIGits Query display resolution ENABle lt b gt Turn front panel display on or off Note 1 vV ENABle Query display state vV WINDow 1 Path to control user text messages Vv TEXT Note 2 Vv DATA lt a gt Define ASCII message a up to 12 characters V DATA Read text message v STATe lt b gt Enable or disable text message mode Note 3 vV STATe Query state of text message mode vV Notes 1 RST and
119. Rear Panel Step 5 Disable zero check and take a reading from the display If the readings are noisy you may want to use damping and or filtering to reduce noise Use filtering if the noise is caused by a noisy input signal and use damping if noise is caused by input capacitance Filtering is covered in Section 6 and damping is discussed next Damping High capacitance seen at the input will increase reading noise This capacitance can be attrib uted to a long input cable or to the capacitance of the source or a combination of both Enabling damping will reduce this type of noise for current measurements However damping will also slow down the response of the measurement Perform the following steps to enable or disable damping 1 Press DAMP to display the present state of damping 2 Use the a or w key to display ON or OFF 3 Press ENTER Amps M easurements 4 5 High impedance measurement techniques Significant leakage could occur across a high impedance gt 1GQ DUT through the insulators as shown in Figure 4 3A where R and R represent the leakage resistance Instead of measur ing just the current Ip through R you are also measuring the leakage current I The current measured by the ammeter is Ip By connecting ammeter input LO to the metal mounting guard plate as shown in Figure 4 2B the leakage current I is shunted to ammeter input LO and is not measured by the amme ter Therefore the amm
120. SOURce2 lt name gt Select data format for reading output patterns ASC Sec 10 ASCii HEXadecimal OCTal or BINary Note RST default is NORMal SYSTem PRESet default is SWAPped A FORMat DATA lt type gt lt ength gt Parameters ASCii ASCII format REAL 32 Binary IEEE 754 single precision format SREal Binary IEEE 754 single precision format NOTE lt length gt is not used for the ASCii or SREal parameters It is optional for the REAL parameter If you do not use lt length gt with REAL lt length gt defaults to 32 single precision format The double precision format lt length gt 64 is not supported by Model 6514 The response to READ FETCh MEASure TRACe DATA CALC1 DATA or CALC2 DATA over the GPIB can be returned in either the ASCii or binary format All other queries are returned in ASCii regardless of the selected format Over the RS 232 interface only the ASCII format is allowed NOTE Regardless of which data format for output strings is selected the instrument will only respond to input commands using the ASCII format ASCII data format The ASCII data format is in a direct readable form for the operator Most BASIC languages easily convert ASCII mantissa and exponent to other formats However some speed is compro mised to accommodate the conversion Figure 16 1 shows an example ASCII string that includes all the data elements See ELEMents for information on the data elements DI
121. SPlay FORM at and SYSTem 16 5 Figure 16 1 also shows the byte order of the data string Data elements not specified by the ELEMents command are simply not included in the string Figure 16 1 1 040564E 06 2 236299E 02 1 380000E 02 ASCII data format Reading Timestamp Status lE E E 754 single precision format REAL 32 or SREal will select the binary IEEE 754 single precision data format Figure 16 2 shows the normal byte order format for each data element For example if all three data elements are selected the data string for each reading conversion is made up of three 4 byte data blocks Note that the data string for each reading conversion is preceded by a 2 byte header that is the binary equivalent of an ASCII sign and 0 Figure 16 2 does not show the byte for the terminator that is attached to the end of each data string Note that the byte order of the data string can be sent in reverse order see BORDer Figure 16 2 Header Byte 1 Byte 2 Byte 3 Byte 4 IEEE 754 single rrrrrererflourrrrrerfaurarrrerd furavrads ol Pororrtbtb bf te tet to bt bt bt yf bt bt to bob ot bt yo bt bt to tot td precision data ENO Cee Oc Ee i a T a a ae format 32 data Pieces Ort Or Ofaa bits s sign bit 0 positive 1 negative e exponent bits 8 f fraction bits 23 Normal byte order shown For swapped byte order bytes sent in reverse order Header Byte 4 Byte 3 Byte 2 Byte 1 The header a
122. T 250V PK DIGITAL I O TRIGGER LINK RS232 LINE RATING INPUT PREAMP A 50 0H PREAMP o oa on 10K our FUSE LINE m Eoia ASIT 630mAT 100 VAC v 2 GUARD INPUT 8 OVA A iy COM PROGRAMMABLE 315mAT 220 VAC INTERNAL 88 240 VAC CAUTION FoR CONTINUED PROTECTION AGAINST FIRE H 6514 Rear Panel Step 7 Take the charge reading from the display If using auto discharge use the REL key to zero the display when the integrator resets Remember that Rel was enabled in Step 5 Therefore you will have to press REL twice The first press disables Rel and the second press re enables it to zero the display See Auto Discharge Hop in Coulombs Measurement Considerations in this section Coulombs M easurements 5 5 SCPI programming Table 5 1 SCPI commands coulombs function Commands Description Default Ref SENSe SENSe Subystem FUNCtion CHARge Select coulombs function VOLT A DATA Return latest raw reading B CHARge ADIScharge Auto discharge STATe lt b gt Enable or disable auto discharge OFF LEVel lt NRf gt Set auto discharge level 2 le 5 to 2 le 5 2e 6 INITiate Trigger one or more readings B READ Trigger and return reading s B A SENSe FUNCtion lt name gt Parameters CHARge Coulombs function CURRent Amps function VOLTage Volts function RESistance Ohms function Note that the parameter names are enc
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124. TO ON SYST ZCH OFF CALC2 NULL STAT ON ai READ Coulombs measurement considerations Some considerations for making accurate Coulombs measurements are summarized as fol lows Additional measurement considerations are covered in Appendix C For comprehensive information on precision measurements refer to the Low Level Measurements handbook which is available from Keithley Instruments Input bias current A primary consideration when making charge measurements is the input bias offset current of the integrating amplifier Any such current is integrated along with the input signal and reflected in the final reading Model 6514 has a maximum input bias of 4fA for charge at Tear temperature at time of calibration This input offset translates into a charge of 4fC per second at the Tear temperature This value must be subtracted from the final reading to obtain the cor rect value Input bias current may be reduced by performing the offset correction procedure explained in Section 19 External voltage source When using an external voltage source the input current should be limited to less than 1mA by placing a resistor in series with the high input lead The value of this resistor should be at least R 1000 x V ohms where V is the voltage across the resistor or the compliance of the current being integrated Coulombs M easurements 5 7 Zero check hop and auto discharge hop
125. Table B 1 D Table D 1 SCPI Reference Tables CALCulate command summary 0 0 0 0 cece eeeeeeeeteeeereeeeeee 17 2 FORMat command summary 0 0 0 eee eeeeeeeeeeeeeeeeeeeeeeeeene 17 5 DISPlay command summary 0 0 ce eeeeeeeeeeeeeeeeeeeeeeeeee 17 5 SENSe command summary 0 eee eseeeeeecseessecneeeneeseeaes 17 6 STATus command summary eee ece esses cseessecseeeaeeneeees 17 9 SOURce command summary 0 cece eeeeeeeseeeeeeneeeecseeeees 17 9 SYSTem command summary ou eee eee eeeeeeceseeeeeeeees 17 11 TRACe command summary ou eeeceeeeseeseeeeeeseeeeeeeesaee 17 12 TRIGger command sUMMALY 200 ee eee eee ereeeeeeeeeeee 17 13 Performance Verification Recommended verification equipment 0 0 0 eeeeeeeeeseeeeeeee 18 4 Voltage measurement accuracy reading limits 0 18 11 20mA 20mA range current measurement accuracy reading liMitS oss caste dietastecsias eeatsavsboshans E EEE EE 18 13 20pA 2uA range current measurement accuracy redding liMitS ics iicedssevesteet sks esobieesccdens cache EEE TE 18 14 2kQ 20M Q range resistance measurement ACCULACY IMIS 23s cssesctiecuecteeoss jobsdcevocbsnbeceueresiaeacoenesnsvese 18 16 200MQ2 200GQ resistance measurement ACCULACY IMIS escacier esseen aa oaea 18 17 Coulombs measurement accuracy reading limits 18 19 Calibration Recommended calibration equipment 0 0 0 eee eee 19 4 Calibration Menu vssiccvsccsasevesssessseivescansstapsesuntasadbeances
126. The READ command can be used to return fresh readings This command triggers and returns the readings See Section 15 for details Programming example The following command sequence will perform one zero corrected amps measurement RST Return 6514 to RST defaults SYST ZCH ON Enable zero check FUNC CURR Select the Amps function CURR RANG 20e 12 Select the 20pA range SYST ZCOR ON Perform zero correction CURR RANG AUTO ON Enable auto range SYST ZCH OFF Disable zero check READ Trigger and return one reading Amps measurement considerations Some considerations for making accurate amps measurements are summarized as follows Additional measurement considerations are covered in Appendix C For comprehensive infor mation on precision measurements refer to the Low Level Measurements handbook which is available from Keithley Instruments Input bias current An ideal ammeter would read 0A with an open input In practice however ammeters do have some current that flows when the input is open This current is known as the input bias offset current and may be large enough to corrupt low current measurements The input bias current for Model 6514 is listed in the specifications Input bias current may be reduced by performing the current offset correction procedure explained in Section 19 Voltage burden The input resistance of the ammeter causes a small voltage drop across the input terminal
127. UTO range key will initially select the 2uA range and then enable autorange If the range group is then changed to LOW the instrument will initially go to the 200nC range with autorange enabled Therefore the instrument will always stay within the selected range group with autorange enabled NOTE With the low range group selected the OVERFLOW message will be displayed when the input signal exceeds 210nC Perform the following steps to select autorange group for Q 1 Select the Q function 2 Press Shift and then one of the follow RANGE keys a Press the RANGE a key to select the HIGH range group 2uC and 20uC b Press the RANGE y key to select the LOW range group 20nC and 200nC 6 4 Range U nits Digits Rate and Filters Units Readings can be displayed using engineering ENG units i e 1 236 MQ or scientific SCI notation i e 1 236E 06 Perform the following steps to change the units setting 1 Press SHIFT and then DIGIT to display the present units setting ENG or SCI 2 Press the RANGE 4 or y key to display the desired units setting 3 Press ENTER NOTE _ 1 The units setting can only be changed from the front panel no remote operation 2 Scientific notation provides more resolution on small values than engineering units Digits The DIGIT key sets display resolution for Model 6514 Display resolution can be set from 3 to 62 digits This single global setting affects display resolution for
128. Use the enclosure in Figure 11 8 to shield the device 11 16 Digital I O Analog O utputs and External Feedback Frequency compensation stabilization is accomplished by adding a feedback capacitor Crp The value of this capacitor depends on the particular transistor being used and the maximum cur rent level expected Compensation at maximum current is required because the dynamic imped ance will be minimum at this point It should be noted that the response speed at lower currents will be compromised due to the increasing dynamic impedance which is given by the following formula Using the above transistors a minimum RC time constant of 100usec at maximum input cur rent would be used At In max of 100A this value would correspond to 0 4uF Note that at 100nA this value would increase the RC response time constant to 100msec A minimum capac itance of 100pF is recommended Although the input signal to this particular circuit is assumed to be a current conversion to voltage input could be performed by placing a shunt resistor across the input However the nom inal voltage burden of 1mV must be considered as an error signal that must be taken into account Further processing of the current response can be achieved by using the suppress feature For example REL could be enabled with a reference input current applied For all subsequent cur rents the natural logarithm of the ratio of the measured current to the suppressed current w
129. V FEED Query source of readings for buffer vV TSTamp Timestamp FORMat lt name gt Select timestamp format ABSolute or DELta ABS FORMat Query timestamp format Note SYSTem PRESet and RST have no effect on the commands in this subsystem The listed defaults are power on defaul SCPI Reference Tables 17 13 Table 17 9 TRIGger command summary Default Command Description parameter Ref SCPI INITiate Path to initiate measurement cycle s Sec 9 vV IMMediate Initiate one trigger cycle V ABORt Reset trigger system goes to idle state vV ARM SEQuence 1 Path to configure arm layer v LAYer 1 SOURce lt name gt Select control source IMMediate TIMer BUS IMMediate v TLINk STESt PSTest NSTest BSTest or MANual SOURce Query arm control source Vv COUNt lt n gt Set measure count 1 to 2500 or INF infinite 1 Vv COUNt Query measure count vV TIMer lt n gt Set timer interval 0 001 to 99999 999 sec 0 100 Vv TIMer Query timer interval vV TCONfigure v DIRection lt name gt Enable SOURce or disable ACCeptor ACCeptor v bypass DIRection Query arm source bypass vV ASYNchronous Configure input output triggers ILINe lt NRf gt Select input trigger line 1 2 3 4 5 or 6 1 ILINe Query input trigger line OLINe lt NRf gt Select output trigger line 1 2 3 4 5 or 6 2 OLINe Query output trigger line OUTPut lt name gt Output tr
130. YST AZER ON Enable autozero Clean up and quit CLOSE 1 Close file CLEAR Clear interface END F IEEE 488 Bus O verview F 2 IEEE 488 Bus O verview Introduction The IEEE 488 bus is a communication system between two or more electronic devices A device can be either an instrument or a computer When a computer is used on the bus it serves as a supervisor of the communication exchange between all the devices and is known as the con troller Supervision by the controller consists of determining which device will talk and which device will listen As a talker a device will output information and as a listener a device will receive information To simplify the task of keeping track of the devices a unique address num ber is assigned to each On the bus only one device can talk at a time and is addressed to talk by the controller The device that is talking is known as the active talker The devices that need to listen to the talker are addressed to listen by the controller Each listener is then referred to as an active listener Devices that do not need to listen are instructed to unlisten The reason for the unlisten instruc tion is to optimize the speed of bus information transfer since the task of listening takes up bus time Through the use of control lines a handshake sequence takes place in the transfer process of information from a talker to a listener This handshake sequence helps ensure the credibil
131. age replace the fuse only with the type and rating listed If the instrument repeatedly blows fuses it will require servicing 3 Ifconfiguring the instrument for a different line voltage remove the line voltage selector from the assembly and rotate it to the proper position When the selector is installed into the fuse holder assembly the correct line voltage appears inverted in the window 4 Install the fuse holder assembly into the power module by pushing it in until it locks in place Routine Maintenance 20 3 Figure 20 1 Model 6514 Electrometer Power module Rial aaa Ag r ven 00 g gt O 0m0 owo oE 0 Window Fuse Holder Assembly Table 20 1 Power line fuse Line voltage Rating K eithley part no 100 120V 0 63A 250V 5x20mm FU 106 630 slow blow 220 240V 0 315A 250V 5x20mm FU 106 315 slow blow 20 4 Routine Maintenance Front panel tests The front panel tests are summarized in Table 20 2 To run a test simply press SHIFT then TEST then scroll through the menu choices and press ENTER Table 20 2 Front panel tests Test Description DISP Test display KEY Test front panel keys DISP test The display test allows you to verify that each segment and annunciator in the vacuum fluo rescent display is working properly Perform the following steps to run the display test 1 KEY test Press SHIFT and then TEST to acce
132. ail pattern has to be HI HI HI LO When the failure occurs line 4 will be pulled low and the DUT will be placed in the bin assigned to that pulsed line If the handler requires a high going pulse the four digital output lines of Model 6514 must initially be set low The LO LO LO LO clear pattern represents the no action condition for the handler When one of those lines are pulled high by a defined pass or fail bit pattern i e LO LO LO HD the DUT will be placed in the bit assigned to that pulsed line Category register component handler When using this type of handler Model 6514 sends a bit pattern to three handler lines when a pass or fail condition occurs This bit pattern determines the bin assignment for the DUT With the pass fail pattern on the output line 4 is then pulsed This EOT end of test pulse latches the bit pattern into the register of the handler which places the DUT in the assigned bin When interfacing to this type of handler a maximum of eight component handler bins are supported 10 8 Limit Tests If the handler requires a low going EOT pulse line 4 of the digital output must initially be set high When the EOT line is pulsed low the binning operation occurs When using the CON FIG LIMITS MENU to define pass fail bit patterns line 4 must be set low If for example the required fail pattern by the handler is HI LO HI then you must define the fail pattern of the test to be HI LO HI
133. al 128 64 32 16 8 4 2 Weights 27 25 25 24 23 22 29 PON Power On amp Logical AND URQ User Request OR Logical OR CME Command Error EXE Execution Error DDE Device Dependent Error QYE Query Error OPC Operation Complete Standard Event Register Standard Event Enable Register Status Structure 13 13 O peration event status The used bits of the operation event register shown in Figure 13 5 are described as follows e Bit BO calibrating Set bit indicates that Model 6514 is calibrating e Bit B5 waiting for trigger event Trig Set bit indicates that Model 6514 is in the trigger layer waiting for a TLINK trigger event to occur e Bit B6 waiting for arm event Arm Set bit indicates that Model 6514 is in the arm layer waiting for an arm event to occur e Bit B10 idle state Idle Set bit indicates Model 6514 is in the idle state Figure 13 5 CONDition Idle Arm Trig Cal Operation Condition Operation event B15 B11 B10 B9 B7 B6 B5 B4 B1 BO Regiser EVEN t Idle Arm Trig a Cal Operation Event B15 B11 B10 B9 B7 B6 B5 B4 B1 BO Regiser To OPC bit lg j of Status Byte OR Register Ba amp F Idle Arm Trig OPC Operation Event ENABLE SNR 15 811 B610 89 87 B6 B5 B4 B1 Bo Enable
134. all measurement functions To set display resolution press and release the DIGIT key until the desired number of digits is displayed NOTE Changing the integration rate changes display resolution but changing display reso lution does not change the rate setting see RATE for details SCPI programming range and digits Table 6 2 SCPI commands range and digits Commands Description Default For Range SENSe SENSe Subsystem VOLTage Measure voltage RANGe Range selection UPPer lt n gt Specify expected reading 210 to 210 V 20V AUTO lt b gt Enable or disable autorange see Note ULIMit lt n gt Specify upper range limit for autorange 210 to 210 V 200V LLIMit lt n gt Specify lower range limit for autorange 210 to 210 V 2V Range Units Digits Rate and Filters 6 5 Table 6 2 cont SCPI commands range and digits Commands Description Default CURRent Measure current RANGe Range selection UPPer lt n gt Specify expected reading 0 021 to 0 021 A 200uA AUTO lt b gt Enable or disable autorange see Note ULIMit lt n gt Specify upper range limit for autorange 0 021 to 0 021 A 20mA LLIMit lt n gt Specify lower range limit for autorange 0 021 to 0 021 A 20pA RESistance Measure resistance RANGe Range selection UPPer lt n gt Specify expected reading 0 to 2 1e11 Q 200kQ AUTO lt b gt Enable or disable autorange see No
135. an examine the state of the SRQ line without performing a serial poll thereby detecting when the 6514 has completed its task without interrupting it in the process The following example program segment sets up the Model 6514 to assert SRQ when the reading buffer has completely filled and then arms the reading buffer initiates readings and waits for the Model 6514 to indicate that the buffer is full This is not acomplete program The commands to configure the trigger model and the reading buffer see the next example are not shown The example shown here can be modified for any event in the Model 6514 status reporting system For QuickBASIC 4 5 and CEC PC488 interface card edit the following line where the QuickBASIC libraries are on your computer SINCLUDE c qb45 ieeeqb bi I nitialize the CEC interface as address 21 CALL initialize 21 0 Reset STATus subsystem not affected by RST CALL SEND 14 stat pres cls status CALL SEND 14 stat meas enab 512 status enable BFL CALL SEND 14 sre 1 status enable MSB CALL SEND 14 trac feed cont next statuss Start everything CALL SEND 14 init status WaitSRQ IF NOT srq THEN GOTO WaitSRQ CALL SPOLL 14 poll status IF poll S AND 64 0 THEN GOTO WaitSRQ After the program has detected an asserted SRQ line it serial polls the Model 6514 to deter mine if it is th
136. ands reset registers and ClEAL QUEUES ccsssaccessersea cies scisaecvsatisbastaevessasteonreastasipesteatss 13 4 SCPI command data formats for reading Statis TESISLETS ciscscsscsoescesastsonencbetissbceais senptensacnvesesenesbsaste 13 6 Common commands status byte and service request CMADILS TESISLELS is csesscvsenccbascssaessoansseacenihszassentocseestatupcsenatys 13 9 Common and SCPI commands condition registers 13 16 Common and SCPI commands event registers 13 16 Common and SCPI commands event enable TEDISTETS sisaendicdastscnsaveastased E raTa EEEE ERE ETEA E E EEEE 13 17 SCPI commands error queue 0 0 ce eee eeeeeeceeeeseeteeeeees 13 20 Common Commands TEEE 488 2 common commands and queries 14 2 SCPI Signal O riented Measurement Commands Signal oriented measurement command summary 15 2 DISPlay FO RMat and SYSTem SCPI commands display 00 eee eeeeeeeeseeeeceeeeeeeeeeeeeeees 16 2 SCPI commands data format 00 0 eee ee eeeeeeeeeeeeeeees 16 4 SCPI commands system 0 eee eeeeseesseeseceeeeereeeeeeeeees 16 8 17 Table 17 1 Table 17 2 Table 17 3 Table 17 4 Table 17 5 Table 17 6 Table 17 7 Table 17 8 Table 17 9 18 Table 18 1 Table 18 2 Table 18 3 Table 18 4 Table 18 5 Table 18 6 Table 18 7 19 Table 19 1 Table 19 2 Table 19 3 Table 19 4 Table 19 5 Table 19 6 Table 19 7 20 Table 20 1 Table 20 2
137. ands are used by the controller to remove any talkers or listeners from the bus ATN is true when these commands are asserted UNL Unlisten Listeners are placed in the listener idle state by the UNL command UNT Untalk Any previously commanded talkers will be placed in the talker idle state by the UNT command F 10 EEE 488 Bus Overview Common commands Common commands are commands that are common to all devices on the bus These com mands are designated and defined by the IEEE 488 2 standard Generally these commands are sent as one or more ASCII characters that tell the device to perform a common operation such as reset The IEEE 488 bus treats these commands as data in that ATN is false when the commands are transmitted SCPI commands SCPI commands are commands that are particular to each device on the bus These com mands are designated by the instrument manufacturer and are based on the instrument model defined by the Standard Commands for Programmable Instruments SCPI Consortium s SCPI standard Generally these commands are sent as one or more ASCII characters that tell the device to perform a particular operation such as setting a range or closing a relay The IEEE 488 bus treats these commands as data in that ATN is false when the commands are transmitted Command codes Command codes for the various commands that use the data lines are summarized in Figure F 3 Hexadecimal and the decimal values for
138. arded Ohms measurements With guard on Figure 2 1B the driven guard is connected to the inner shell of the triax con nector Input low is accessed via the COMMON terminal through an internal 0 1 fuse This configuration is used for guarded Volts and guarded Ohms measurements only The GRD key toggles guard on and off NOTE The state of guard on or off has no affect on the Amps and Coulombs functions The unguarded configuration is always selected for the Amps and Coulombs functions Figure 2 1 Input High Input connector configurations Input Low INPUT Chassis Ground 250V PEAK Volts Amps Ohms amp Coulombs A Unguarded GRD off Input High 7 lt 1Q Guard K Fuse ____ Chassis INPUT Ground COMMON Input Low 250V PEAK Volts and Ohms only B Guarded GRD on M easurement Concepts 2 5 Maximum input levels The maximum input levels to Model 6514 are summarized in Figure 2 2 WARNING Themaximum common mode input voltage which is the voltage between theinput HI or LO and chassis ground is 500V peak Exceeding this value may create a shock hazard CAUTION Connecting PREAMP OUT COMMON or 2V ANALOG OUTPUT to earth while floating the input may damage the instrument Figure 2 2 Input High Maximum input levels M ax Input Signal j Input Low 500V Peak Chassis Ground O Max Input Signal 250V Peak DC to 60Hz sine wave 10 seconds maximum in mA ranges 500V Peak Low noise in
139. arth Ground COMMON NOTE GRD must be on Test fixture Whenever possible use a shielded low leakage test fixture to make precision measurements A general purpose test fixture is shown in Figure 2 6 This test fixture will accommodate a vari ety of connection requirements Figure 2 6 General purpose test fixture DUT Metal Guard Plate B 3 Lug Female Triax Connector Metal Chassis ___ To External a Source Ce ce To 6514 Input Se To 6514 COMMON amp A Banana Jacks Test fixture chassis M easurement Concepts 2 9 Insulated Terminal Post 6 AT gt Safety j Earth ea Ground e The chassis of the test fixture should be metal so that it can function as a shield for the DUT or test circuit The metal chassis should be connected to chassis ground of Model 6514 via the triax cable e The test box must have a lid that closes to prevent contact with live circuitry e The test fixture must have a screw terminal that is used exclusively for connection to safety earth ground WARNING To provide protection from shock hazards the test fixture chassis must be properly connected to safety earth ground A grounding wire 18 AWG or larger must be attached securely to the test fixture at a screw terminal designed for safety grounding T he other end of the ground wire must be attached to a known safety earth g
140. as a timestamp The timestamp for each reading is referenced to the time the measure store process is started In addition recalled data includes statistical information maximum minimum peak to peak average and standard deviation The buffer fills with the specified number of readings and stops Readings are placed in the buffer after any math operations are performed Math operations include relative mX b percent or limits Buffered data is overwritten each time the storage operation is selected The data is volatile it is not saved through a power cycle Measurement function changes are permissible during the storage process Note however that the statistics will be based on the readings of the different measurement functions Perform the following steps to store readings I Set up the instrument for the desired configuration Press the STORE key Use the cursor keys and p and the RANGE keys and y to set the number of readings to store 1 to 2500 Press ENTER to enable the buffer If in the immediate trigger mode the storage process will start immediately If in the external input trigger mode each input trigger or press of TRIG key will store a reading See Section 9 for information on triggering NOTE The asterisk annunciator turns on to indicate that the data storage operation is Recall enabled It will turn off when the storage process is finished buffer full Perform the following steps to view st
141. assis Typically 101092 in parallel with 500pE INPUT CONNECTOR Three lug triaxial on rear panel 2V ANALOG OUTPUT 2V for full range input Inverting in Amps and Coulombs mode Output impedance 10kQ PREAMP OUTPUT Provides a guard output for Volts measurements Can be used as an inverting output or with external feedback in Amps and Coulombs modes DIGITAL INTERFACE Handler Interface Start of test end of test 3 category bits Digital I O 1 Trigger input 4 outputs with 500mA sink capability Connector 9 Pin D subminiature male pins EMC Conforms with European Union Directive 89 336 EEC EN55011 EN50082 1 EN61000 3 2 EN61000 3 3 FCC part 15 class B SAFETY Conforms with European Union Directive 73 23 EEC EN61010 1 GUARD Switchable voltage and ohm guard available TRIGGER LINE Available see manual for usage READING STORAGE 2500 readings READING RATE To internal buffer 1200 readings second To IEEE 488 bus 500 readings secondh3 To front panel 17 readings second at 60Hz 2 2 15 readings second at 50Hz Notes 10 01 PLC digital filters off front panel off auto zero off 21 00 PLC digital filters off 3 Binary transfer mode DIGITAL FILTER Median and averaging selectable from 2 to 100 readings DAMPING User selectable on Amps function ENVIRONMENT Operating 0 50 C relative humidity 70 non condensing up to 35 C Storage 25 to 65 C WARM UP 1 hour to rated accuracy see manual for recommend
142. asurement process After sending the INITiate command to start the measure ment process use the ABORt command to abort the measurement process then use DATA LATest to return the last CALC2 reading Sending DATA or DATA LATest without first sending INITiate will return old readings or cause an error 220 if limit is not enabled or there are no readings available E ARM SOURce lt name gt Typical start of test options e IMMediate Test starts when LIMIT key is pressed e NSTest Test starts when component handler pulls the SOT line low e PSTest Test starts when component handler pulls the SOT line high Limit Tests 10 15 Programming example The following command sequence will test DUT using the limit tests example shown in Fig ure 10 2 RST Restore RST defaults Volts function CALC2 LIM UPP 2 Set upper limit for Limit 1 2V CALC2 LIM LOW 2 Set lower limit for Limit 1 2V CALC2 LIM STAT ON Enable Limit 1 test CALC2 LIM2 UPP 1 Set upper limit for Limit 2 1V CALC2 LIM2 LOW 1 Set lower limit for Limit 2 1V CALC2 LIM2 STAT ON Enable Limit 2 test Connect DUT to input INIT Perform tests on DUT one measure ment CALC2 LIM FAIL Return result of Limit 1 test CALC2 LIM2 FAIL Return result of Limit 2 test dl Digital I O Analog O utouts and Extemal Feedback Digital I O port Explains how to u
143. ated from the VAL key Relative mX b and Percent 7 3 VAL key The SHIFT VAL key sequence displays the present Rel value From this display you can enable Rel using that Rel value or you can key in a different Rel value 1 Press SHIFT and then VAL to display the present Rel value To change the Rel value use the lt gt a and w keys to change the value To change polar ity place the cursor on the polarity sign and press A or V To change range place the cur sor on the range symbol at the end of the reading and use the A and y keys see Table 7 1 3 With the desired Rel value displayed press ENTER to enable Rel Table 7 1 Range symbols for rel values Symbol Prefix Exponent P pico 10 N nano 10 u micro 10 m milli 10 j none 10 K kilo 103 M mega 10 G giga 10 T tera 10 SCPI programming relative Table 7 2 SCPI commands relative null Commands Description Default Ref CALCulate2 CALCulate2 Subsystem FEED lt name gt Specify reading to Rel SENSe 1 or CALCulate 1 SENS A NULL Configure and control Relative ACQuire Use input signal as Rel value OFFSet lt NRf gt Specify Rel value 9 999999e20 to 9 999999e20 0 0 STATe lt b gt Enable or disable Rel OFF DATA Return Rel ed readings triggered by INITiate B LATest Return only the latest Rel ed reading B INITiate Trigger one or more readings 7 4 Relative
144. ation charge 20nC 20 00000V 1nF 20nC 20 00000V 1nF 20nC 200nC 200 0000V 1nF 200nC 200 0000V 1nF 200nC 2uC 20 00000V 100nF 2uC 20 00000V 100nF 2uC 20uC 200 0000V 100nF 20uC 200 0000V 100nF 20uC l Nominal value Based on nominal capacitance values Calculate actual charge from calibrator voltage and actual standard capacitance value Q CV Calibrate positive full scale and negative full scale values for each range 19 16 Calibration Ohms calibration NOTE Calibration is required only for the 2kQ 2MQ and the 2GQ ranges However other 1 Figure 19 5 Connections for ohms calibration 2kQ and 2MQ Input ranges pa Model 6514 Electromete ranges may also be calibrated using appropriate calibration resistances if desired Volts should be calibrated before ohms Connect the triax short to the INPUT jack triax alligator cable with red and black leads connected together Low noise Coax BNC Cable Calibrator Output r BNC to dual Resistance Calibrator Banana Plug Adapter Connect Cable Shield to Output LO Select Model 6514 ohms function by pressing the Q key Select Model 6514 2k range Press SHIFT then CAL At the CAL RUN prompt press ENTER The unit will prompt as follows 2KOHM ZERO NOTE Zero calibration is performed only on the 2kQ range 5 10 11 Press ENTER The unit will prompt for the
145. ator between the shield and the inner conductor is being measured The cable sample should be kept as short as possible to minimize input capacitance to the ammeter For this test a fixed bias voltage is applied across the insulator for a specified time to allow the charging effects of cable capacitance to stabilize The current is then measured Cable resis tance R can then be calculated as follows R V I where V is the sourced bias voltage I is the measured current Figure 4 8 e M e Connections cable HI Cable HI A ah Resistance 6 insulation resistance 230 514 V Source Ammeter test z LO LO Equivalent Circuit Amps M easurements 4 15 Surface insulation resistance SIR NOTE For this test Model 6514 uses the source voltage measure current method to determine resistance Once a current measurement is performed resistance can be calculated Figure 4 9 shows how to measure the insulation resistance between PC board traces Note that the drawing shows a Y test pattern for the measurement This is a typical test pattern for SIR tests A bias voltage typically 50V is applied to the test pattern for a specified time typically one second to polarize the test pattern The test voltage typically 100V is then applied and after a specified time typically one second Model 6514 measures the current Surface insulation resistance can now be calculated as follows SIR V I where V is the
146. ay want to close a switching channel and measure the resistance of a DUT connected to that channel Such a test system is shown in Figure 9 7 which uses a Model 6514 to measure 10 DUTs switched by a Model 7011 multiplexer card in a Model 7001 or 7002 switch system Figure 9 7 7001 or 7002 Switch System DUT test ce system Model 6514 Electrometer cm Ti J Trigger Link Trigger Link Link Cable 8501 Triggering 9 13 The trigger link connections for this test system are shown in Figure 9 8 The trigger link of Model 6514 is connected to the trigger link IN or OUT of the switching mainframe Note that with the default trigger settings of the switching mainframe line 1 is an input and line 2 is an output Figure 9 8 7001 or 7002 Switch System Model 6514 Electrometer Trigger irna EER _ v link con nections n Trigger Link Trigger ed Link Cable 8501 For this example Model 6514 and switching mainframe are configured as follows Model 6514 Switching Mainframe Factory Defaults Restored Factory Defaults Restored Trig In Event TLink Scan List 1 1 1 10 Trigger Input Line 2 Number of Scans 1 Trigger Output Line 1 Channel Spacing TrigLink Trigger Output Event ON Trigger Count 10 Trigger Delay Auto To store readings in Model 6514 buffer press STORE and set the buffer size to 10 When ENTER is pressed the asterisk annunciator turns on to indica
147. be small signal types and should be in a light tight enclosure Amps M easurements 4 13 Applications The following applications require an external voltage source The Keithley Model 230 volt age source is fully programmable and can source up to 100V at 100mA With the proper use of external triggering between Models 6514 and 230 the tests can be automated All of the applications require a bias time or delay which can be provided by the delay feature of Model 6514 When Model 6514 is triggered a measurement will not be per formed until the delay period expires NOTE External triggering and delay are covered in Section 9 Diode leakage current Figure 4 6 shows how to measure the leakage current for a diode By sourcing a positive volt age the leakage current through the diode will be measured Note that if you source a negative voltage you will forward bias the diode Resistor R is used to limit current in the event that the diode shorts out or it becomes forward biased Select a value of R that will limit current to20mA or less A profile for leakage current can be developed by measuring current at various voltage levels For example you can program Model 230 to source from 1 to 10V in 1V steps With the proper use of external triggering Model 6514 will perform a current measurement on each voltage step To ensure that the voltage is settled before each current measurement you can program Model 6514 for a delay For exampl
148. cation cccccecsseeereeeseeeeeeees 18 10 Connections for 20HA 20mA range verification 18 12 Connections for 20pA 20uA range verification 18 13 Connections for ohms verification 2kQ 20MQ ranges 18 15 Connections for ohms verification 200ME2 200GQ2 ranges eeeeceeeeceeeeeseceeeecteeeeeeeeee 18 17 Connections for coulombs verification ccccceeeeeeees 18 18 Calibration Connections for volts calibration 0 e ee eeeeeeeeeereeeeeeeeeeeees 19 8 Connections for 20uA 20mA range calibration 19 10 Connections for 20pA 2mA range calibration 19 11 Connections for coulombs calibration cccceeeseeeeeee 19 14 Connections for ohms calibration 2kQ and 2MQ ranges 00 ee eeeeeceeeecseceeneeeeeeeseeeeeneees 19 16 Connections for ohms calibration 2GQ range 19 17 Routine Maintenance Power module se eeeeeseceseeceseeeeeeceeeecseceeeeeeeeeaaeceeeenaeeenees 20 3 C Figure C 1 Figure C 2 F Figure F 1 Figure F 2 Figure F 3 H Figure H 1 General Measurement Considerations Power line ground l00p8 cc ceeeeceseeseeeeceeeeeeeeseeeeeeseeeneeaee C 2 Eliminating ground loops 0 ce ee ceeeeeeeeeeeeeeeeeseeeeeeseeeseeaee C 3 IEEE 488 Bus O verview TEEE 488 bus Configuration 0 0 0 eeesesseeeeeseeeeceeeeceaeeeeeereees F 4 TEEE 488 handshake sequence eceeeeeeesceeeeeeeeeeeeeeenes F 6 Command
149. ck DC Voltage Calibrator Model 6514 Electrometer BN C to dual Banana Plug Adapter o o a Connect Cable Shield to Output LO DOOIE oo oO 10 ODO 0o00 OO O00 Triax Cable 1062 ise momo 10062 int A uor OUPPUT Model 5156 Calibration Standard Low noise Coax Cable Note Connect Calibrator to Appropriate Resistor Link Shield and Chassis 19 11 19 12 Calibration 9 10 11 12 13 14 Select the amps function on Model 6514 Select Model 6514 20pA range Press SHIFT then CAL then press ENTER at the CAL RUN prompt The unit will prompt for the zero calibration point 20PA ZERO Allow the settling time listed in Table 19 5 then press ENTER The instrument will prompt for the positive full scale calibration point 20PA CAL Connect the voltage calibrator and Model 5156 Electrometer Calibration standard to the Model 6514 INPUT jack as shown in Figure 19 3 Initially make connections to the 100GQ resistance Press ENTER The instrument will prompt a full scale calibration current 20 00000 PA Set the calibrator voltage to 2 000000V Calculate the actual calibration current from the calibrator voltage and the actual standard resistor value I V R Adjust Model 6514 display to agree with the calculated current Allow the settling time listed in Table 19 5
150. ck and starts over Response time The various filter parameters have the following effects on the time needed to display store or output a filtered reading Filter type The time to the first reading is the same for both types but thereafter the moving mode yields a faster reading than repeating mode Number of reading conversions Speed and accuracy are tradeoffs 6 10 Range Units Digits Rate and Filters Operation consideration The digital filter operation will reset start over whenever the zero check operation is performed or the function is changed Digital filter configuration and control The AVG key is a toggle action key It will either disable the digital filter display AVER AGE OFF or access the configuration menu to enable the digital filter NOTE For the following procedure use the aand p keys and the RANGE 4 and keys to set values The qand keys provide cursor control while the and keys increment and decrement the value 1 Press the AVG key to display the present number of reading conversions to average filter count 2 Key in desired filter count value 1 to 100 and press ENTER The present filter type repeating or moving is displayed 3 Use the a or w key to display the desired filter type REPEAT or MOVNG AV and press ENTER SCPI programming filters Table 6 4 SCPI commands filters Commands Description Default For median filter SENSe 1 SENSe S
151. ck and zero correct oo eee esse eeeeseeeeeceessecseesaeeeesaes 2 13 Leroi check ga sid che neh tole iis eohae ave es Saeed 2 13 ZTO COOC oiaoi eeri e ceases E E E RE 2 14 SCPI programming zero check and zero correct 2 15 Input bias current and offset voltage calibration 0 2 17 Front panel xc 2siccisec cs itacdecestivs sastiseenssdaseeen ea abrdideeted cd 2 17 SCPI programming 0 0 se eeeeeesseessesseeencesseensessenseeneees 2 18 Measurement considerations ccceeeeeesescececeecececeeeeeeecesesenees 2 19 Volts and O hms Measurements Measurement OVErVieW ooo eee eceseeseeseeesecseeesecsseeaeceeeeeseeeeseeeees 3 2 GUAT S oroen io oN E AA E ENR 3 2 Test circuit leakage scc ssccssscecsessascesveesoasszsescasesssacsseasseicsens 3 2 Input cable leakage and capacitance esesseeessseeeseeereeeeee 3 3 Volts and ohms measurement procedure eee eeeeeeeeees 3 4 V Drop and I Source for ohms 0 00 eee eee eeeeeeeeeeeeeeeeeees 3 6 SCP programing sereset erein s Ei e rE Ee EEE ese 3 7 Programming example sessescriirsiserorsesrodsisessrsnesreseissi 3 8 Volts and ohms measurement considerations 0 0 0 sees 3 9 Loading Effects As cpccifessssacneszatdstevecsintaeiavs2ideesssaesecaconennecaceies 3 9 Cable leakage resistance 0 ee eeeececeeeceeeeeeeeeeeeesenetaeeees 3 9 Input capacitance settling time eee cere ereeeees 3 10 Guarding input cable o eee e ee eeeeeeeeeeeseeeeeceesne
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153. controlling relative e eee ee eseee tees 7 2 SCPI programming relative eee eeeeeeeeeeeeeees 7 3 mX b and percent P eesceececsseesseceeeecseceeeeeeseceseeceeeecseeeeneeeee 7 4 rna DC a o B EE E EE E TS 7 4 Percent Mo os ciscesssescusea cid stds ci tecsegech cape ce aatecddes Ma welavtllecanass 7 5 SCPI programming mX b and percent oe 7 6 Buffer Butler OPStatiOns suics cessicth sates scneeds ener desea asr okn EREA 8 2 LOLS dash sents eh E E E 8 2 Recall ergene an ocon ea tee E EERE E E EA REEE 8 2 Butter Statlsues sissie ierse eesis iom seues oisienedaiik 8 3 SCPI Programme p cscscccscdssccsieecsssonsscesessscesscvessensesocsvseebeesesonsaee 8 4 Programming example 0 0 cece cesses ceeeeeeeeeeeeeeeeeeeeeeneeaes 8 6 Triggering Tee per models pinisrcre isori enr s ssa baste EER 9 2 Idle and initiate srscrececctnc ccc 9 4 Trigger model operation 0 eee eee ceeceseceeceseeeeeeeeeeeeeaes 9 4 Trigger model configuration front panel 0 0 0 eee 9 7 SCPI programming sesse ecenin eerie seere ETE EEE NIR EE KEE RS 9 9 Programming example sssesssseseeseeeeseererrsresrressrrresrrererrer 9 10 External ris Serine sesiis eaea iR 9 11 Input trigger requirements 00 el eee cee eens ceeeeteeeeees 9 11 Output trigger specifications oo ee eee eeteceeeeeeeeeees 9 12 External trigger example 0 0 eee eseeseceeceseceeeeseeenees 9 12 10 11 12 Limit Tests Lit testing 5s decsud detadeesedavegsv
154. d ese a cii ee bt pl a et ee ed M easured 6514 Resistance Ohmmeter tT RC B High Impedance O hms Measurement U nguarded 3 12 Volts and Ohms Measurements Figure 3 6 100 Settling time Percent of Final Value 63 Guarding input cable Guarding should be used for high impedance measurements and for low voltage measure ments that use long input cables To better understand the concept of guarding review the unguarded circuit shown in Figure 3 7 Eg and Rg represents the resistance and voltage components of the source and Ry and C represents the leakage resistance and cable capacitance of the triax input cable The equivalent circuit shows the divider that is formed If Rg is large enough the divider will significantly atten uate the voltage seen at the input of Model 6514 see Cable Leakage Resistance Also Rg and the cable capacitance C could create a long RC time constant resulting in a slow measurement response see Input Capacitance Figure 3 7 Center Unguarded input cable Triax Cable Conductor Source OHI Sh To 6514 Input Es Inner Shield O LO OHI To 6514 CL Input LO Equivalent Circuit Figure 3 8 Guarded input cable Volts and O hms Measurements 3 13 Guarding the circuit minimizes these effects by driving the inner shield of the triax cable at signal potential as shown in Figure 3 8 Here a unity gain amplifier with
155. d Select the DC amps function on Model 6514 and set the calibrator to output DC voltage Set Model 6514 to the 20pA range With zero check enabled zero correct the instrument then disable zero check Set the calibrator voltage to 0 0000V and make sure the output is turned on Enable Model 6514 REL mode Leave REL enabled for the remainder of the test OV SY 18 14 Performance Verification Verify current measurement accuracy for each of the currents listed in Table 18 4 For each test point e Make connections to the indicated calibration standard resistor e Select the correct Model 6514 measurement range e Calculate the actual required calibrator voltage V IR where I is the desired applied current and R is the actual standard resistor value e Set the calibrator to the calculated voltage e Verify that Model 6514 current reading is within the reading limits listed in the table Repeat the procedure for negative source currents with the same magnitudes as those listed in Table 18 4 Table 18 4 20pA 2uA range current measurement accuracy reading limits Nominal Calibration Model calibrator standard Actual Model 6514 amps reading 6514 range voltage resistor Applied current voltage2 limits 1 Year 18 C 28 C 20pA 2V 100GQ 20 0000pA V 19 7970 to 20 2030pA 200pA 2V 10GQ 200 000pA V 197 995 to 202 005pA 2nA 2V 1GQ 2 00000nA V 1 99570 to 2 00430nA 20nA 2V 100MQ 20 0000nA V 19 9595 to 20 04
156. d to configure the trigger model and the commands to control the measurement process E xternal triggering Explains external triggering which allows Model 6514 to trigger other instruments and be triggered by other instruments 9 2 Triggering Trigger models The flowcharts in Figures 9 1 and 9 2 summarize triggering for Model 6514 They are called trigger models because they are modeled after the SCPI commands to control triggering operation Figure 9 1 Turn 6514 ON Trigger model front panel operation Press HALT O Idle Arm Immediate Another Arm Layer GPIB Arm Count ME INF anua A Arm Event ae Test O utput Trigger E gt O n O ff BSTest TL Done Trigger Bypass Layer Trigger Count 1 Immediate Trigger In TLINk Source 0 0 sec O Eo Tigger gt On Off Trigger Delay MEASU RE Action Factory Default gt Output Trigger Triggering 9 3 Figure 9 2 Trigger model remote operation See Note SOU Rce ARM DIRection ARM SOURce IMM ediate ARM SOURce BUS ARM SOURce TIM er ACCeptor ARM SOURce NSTest ARM SOURce PSTest ARM SOURce MANual 2 1 Arm Event Detector ARM SOURce BSTest gt TRIG ger NONE ARM SOURce TLINk Trigger Layer TRIG ger DIRection ACCeptor TRIGger COUNt lt n gt 1 TRIGger SOURce IM Mediate Trigger In Trigger Event TRIGger SOURce TLINK Source Detector TRIG ger D ELay lt n gt TRIGg
157. de 6514 range Calibration resistance 2kQ I 9KQU 2MQ 1 9MQ 2GQ 1GQ Nominal values Use actual values for calibration Use resistance calibrator for 2kQ and 2MQ ranges Use calibration standard resistor for 1GQ range Zero also calibrated on 2kQ range 19 18 Calibration Entering calibration dates and saving calibration NOTE For temporary calibration without saving new calibration constants proceed to Lock ing out calibration Press SHIFT then CAL to access the calibration menu Use either RANGE key to display the following CAL DATES Press ENTER The unit will display DATE 06 15 98 Use the arrow and RANGE keys to set the date then press ENTER The unit will then prompt for the calibration due date NDUE 06 15 99 Set the due date as desired then press ENTER Select CAL SAVE from the calibration menu then press ENTER The unit will prompt as follows SAVE CAL YES With the YES prompt displayed press ENTER to save and lock out calibration The unit will display CAL SAVED NOTE Calibration will also be locked out once saved Locking out calibration Use the following procedure to lock out calibration without saving new calibration constants 1 Press SHIFT then CAL then use the up RANGE key to display the following CAL LOCK Press ENTER The instrument will display the following message CAL LOCKED Changing the calibration code Follow the steps below to change the
158. ding without prefix 1 23456E 00 G2 Reading with prefix and buffer suffix if in B1 NDCV 1 23456E 00 00 012 Hit Key HO Manual trigger Hn Hit front panel key where n 1 to 32 see Figure A 16 3 for key press codes Buffer Size In Set buffer size where n 1 to 2500 B Table D 1 cont Device dependent command summary DDC Emulation Commands Mode Command _ Description Note EOI and Bus Hold off KO Enable both EOI and bus hold off on X K1 Disable EOI enable bus hold off on X K2 Enable EOI disable bus hold off on X K3 Disable both EOI and bus hold off on X Store Calibration none L1 store calibration command not supported SRQ MO Disable SRQ M1 Reading overflow M2 Buffer full M8 Reading done M16 Ready M32 Error Baseline Suppression NO Suppression Rel disabled Rel N1 Suppression Rel enabled Digital Filter PO Filter off P1 Filter off Pn Repeat Filter on where filter size n 2 to 100 C Data Store Buffer QO Conversion rate Ql One reading per second Q2 One reading every 10 seconds Q3 One reading per minute Q4 One reading every 10 minutes Q5 One reading per hour Q6 Trigger mode Q7 Disabled D 3 D 4 DDC Emulation Commands Table D 1 cont Device dependent command summary Mode Command _ Description Note Range V A Q Q XF dbk RO Auto Auto Auto Auto Auto R1 2V 20pA 2kQ 20nC 2V R2 2V 20pA 20kQ 20nC 2V R3 20V 200pA 20
159. dures and proper use of the instrument They must be protected from electric shock and contact with hazardous live circuits Maintenance personnel perform routine procedures on the product to keep it operating properly for example setting the line voltage or replacing consumable materials Maintenance procedures are described in the manual The procedures explicitly state if the operator may perform them Otherwise they should be performed only by service personnel Service personnel are trained to work on live circuits and perform safe installations and repairs of products Only properly trained service personnel may perform installation and service procedures Keithley products are designed for use with electrical signals that are rated Measurement Category I and Measurement Category II as described in the International Electrotechnical Commission IEC Standard IEC 60664 Most measurement control and data I O signals are Measurement Category I and must not be directly connected to mains voltage or to voltage sources with high transient over voltages Measurement Category II connections require protection for high transient over voltages often associated with local AC mains connections Assume all measurement control and data I O connections are for connection to Category I sources unless otherwise marked or described in the Manual Exercise extreme caution when a shock hazard is present Lethal voltage may be present on cable connector jacks o
160. e for instructions Charge is related to capacitance and voltage by the formula Q CV where Q the charge in coulombs C the capacitance in farads V the voltage in volts Model 6514 display will read the charge directly in units determined by the value of C For example a 10uF capacitor will result in a displayed reading of 10uC V In practice the feedback capacitor should be greater than 100pF for feedback stability and of suitable dielectric material to ensure low leakage and low dielectric absorption Polystyrene polypropylene and Teflon dielectric capacitors are examples of capacitor types with these desirable characteristics The capacitor should be mounted in a shielded fixture like the one in Figure 11 8 To discharge the external feedback capacitor enable zero check The discharge time constant will be given by t 10MQ Cpp Allow five time constants for discharge to within 1 of final value External feedback procedure Use the following procedure to operate Model 6514 in the external feedback mode 1 Enable zero check Connect the feedback element between the preamp out terminal and the input HI terminal 3 Enable external feedback as follows a Press the XFBK key to access the external feedback menu b Press the or w key to select ON and press ENTER 4 Press the V key to select the volts function 5 Disable zero check The XF message will be displayed to indicate that the instrument is in the
161. e 0 1 PLC and sets display res olution to 4 2 digit resolution Select the FAST rate if speed is of primary importance at the expense of increased reading noise To change the rate setting press and release the RATE key until the desired rate annunciator SLOW MED or FAST is displayed Range Units Digits Rate and Filters 6 7 NPLC Menu From this menu you can set rate by setting the PLC value Perform the fol lowing steps to set NPLC 1 Press SHIFT and then NPLC to display the present PLC value 2 Use the lt gt a and w keys to display the desired PLC value 0 01 to 10 3 Press ENTER NOTE The SLOW MED or FAST annunciator will only turn on if the set PLC value corre sponds exactly to the slow 5 or 6 PLC medium 1 PLC or fast 0 1 PLC integration rate For example with the integration rate set to 2 PLC none of the rate annuncia tors will turn on SCPI programming rate As shown in Table 6 3 there are four commands to set rate However since the rate setting is global and affects all measurement functions it doesn t matter which command you use to set it Table 6 3 SCPI commands rate Command Description Default SENSe SENSe Subsystem VOLTage NPLCycles lt n gt Specify integration rate 0 01 to 10 PLCs 6 0 60Hz 5 0 50Hz CURRent NPLCycles lt n gt Specify integration rate 0 01 to 10 PLCs 6 0 60Hz 5 0 50Hz RESistance NPLCycles lt n gt Sp
162. e For example INITiate IMMediate These brackets indicate that MMediate is implied optional and does not have to be used Thus the above command can be sent in one of two ways INITiate or INITiate MMediate Notice that the optional command is used without the brackets When using optional command words in your program do not include the brackets e Parameter types The following are some of the common parameter types lt b gt Boolean Used to enable or disable an instrument operation 0 or OFF disables the operation and 1 or ON enables the operation DISPlay ENABle ON Enable the display lt name gt Name parameter Select a parameter name from a listed group lt name gt NEVer NEXT CALCulate FORMat MXB Select Mx B calculation lt NRf gt Numeric representation format A number that can be expressed as an integer e g 8 a real number e g 23 6 or an exponent 2 3E6 TRACe POINts 20 Set buffer size to 20 12 12 Remote O peration lt NDN gt lt n gt Non decimal numeric A non decimal value that can be used to program status enable registers A unique header identifies the format B binary H hexadecimal and Q octal See Programming Enable Registers in Section 13 for details SRE B10001 Set bits BO and B4 of Service Request Enable Register Numeric value Can consist of an NRf number or one of the following name parameters DEFault MINimum or M
163. e if you program Model 6514 for a one second delay each mea surement will be performed after the voltage step is allowed to settle for one second The current measurements can be stored in the buffer NOTE Buffer operation is covered in Section 8 Figure 4 6 R Diode Connections diode AW K leakage current test Hi HI 230 6514 V Source Ammeter LO LO Equivalent Circuit 4 14 Amps Measurements Capacitor leakage current Figure 4 7 shows how to measure the leakage current for a capacitor The magnitude of the leakage is dependent on the type of dielectric and the applied voltage A resistor and a diode are used to limit noise for the measurement For this test a fixed bias voltage is to be applied to the capacitor for a specified time to allow the capacitor to fully charge current decays exponentially with time The leakage current is then measured After the measurement the voltage source is set to output OV for a specified time to allow the capacitor to discharge Figure 4 7 3 D l Connections capacitor leakage current test l HI l raeas l 230 6514 V Source __ Ammeter LO Equivalent Circuit Cable insulation resistance NOTE For this test Model 6514 uses the source voltage measure current method to determine resistance Once a current measurement is performed resistance can be calculated Figure 4 8 shows how to measure the insulation resistance of a cable The resistance of the insul
164. e lt b gt Enable or disable limit 1 test OFF vV STATe Query state of limit 1 test vV FAIL Return result of limit 1 test 0 pass or 1 fail Vv LIMit2 Limit 2 Testing V UPPer Configure upper limit vV DATA lt n gt Set limit 9 99999e20 to 9 99999e20 1 0 v DATA Query upper limit vV SOURce2 lt NDN gt or Specify 4 bit output fail pattern 15 vV lt NRf gt SOURce2 Query output pattern value vV LOWer Configure lower limit vV DATA lt n gt Set limit 9 99999e20 to 9 99999e20 1 0 v DATA Query lower limit v SOURce2 lt NDN gt or Specify 4 bit output fail pattern 15 vV lt NRf gt 17 4 SCPI Reference Tables Table 17 1 cont CALCulate command summary Default Command Description parameter Ref SCPI SOURce2 Query output pattern value V STATe lt b gt Enable or disable limit 2 test OFF vV STATe Query state of limit 2 test vV FAIL Return result of limit 2 test 0 pass or 1 fail Vv CLIMits Composite Limits CLEar Clear I O port and restore it back to SOURce2 TTL settings IMMediate Clears I O port immediately AUTO lt b gt When enabled I O port clears when INITiate ON sent AUTO Query state of auto clear PASS Define pass digital output pattern SOURce2 lt NDN gt or Specify 4 bit pass pattern no failures 15 lt NRf gt SOURce2 Query pass output pattern NULL Configure and control Rel vV AC
165. e 1 PLC for 60Hz is 16 67msec 1 60 and 1 PLC for 50Hz and 400Hz is 20msec 1 50 In general Model 6514 has a parabola like shape for its speed vs noise characteristics and is shown in Figure 6 1 Model 6514 is optimized for the 1 PLC to 10 PLC reading rate At these speeds lowest noise region in the graph Model 6514 will make corrections for its own internal drift and still be fast enough to settle a step response lt 100ms Figure 6 1 A Speed vs noise characteristics Voltage Noise T gt 166 7us 16 67ms 166 67ms Integration Time The rate setting is global for all measurement functions Therefore it does not matter what function is presently selected when you set rate There are two ways to set rate You can select slow medium or fast by using the RATE key or you can set the number of power cycles from the NPLC menu that is accessed by pressing SHIFT and then NPLC Rate K ey The RATE key selections are explained as follows e SLOW Selects the slowest front panel integration time 6 PLC for 60 Hz or 5 PLC for 50 Hz and sets display resolution to 5 2 digit resolution The SLOW rate provides better noise performance at the expense of speed e MED Selects the medium integration time 1 PLC and sets display resolution to 5 2 digit resolution Select the MED rate when a compromise between noise perfor mance and speed is acceptable e FAST Selects the fastest front panel integration tim
166. e 100 readings at the fastest possible rate The read ings are taken sent across the serial port and displayed on the screen Example program controlling the Model 6514 via the RS 232 COM2 port For QuickBASIC 4 5 and CEC PC488 interface card RDS SPACES 1500 Set string space CLS Clear screen PRINT Set COM2 baud rate to 19200 PRINT Set 8 data bits no parity no flow control and CR as Termina tor Configure serial port parameters ComOpen COM2 19200 N 8 1 ASC CD0 CS0 DSO LF OPO RS TB8192 RB8192 OPEN ComOpen FOR RANDOM AS 1 Model 6514 setup commands Note Serial communications only operate with SCPI mode PRINT 1 RST RST defaults PRINT 1 CLS Clear registers PRINT 1 VOLT RANG 10 10V range PRINT 1 SYST AZER OFF Disable autozero PRINT 1 AVER OFF Disable average filter PRINT 1 DISP DIG 4 3 digit resolution PRINT 1 FORM ELEM READ Reading only PRINT 1 VOLT NPLC 0 01 NPIC 0 01 PRINT 1 TRIG COUN 100 100 readings PRINT 1 DISP ENAB OFF Turn off display PRINT 1 INIT Take 6514 out of idle SLEEP 1 Wait one second PRINT 1 READ Perform measurements LINE INPUT 1 RDS Get data PRINT RD Display data on CRT PRINT 1 DISP ENAB ON Turn on display PRINT 1 S
167. e 2 0 cee eecececeeseceeeceneecenceceeeeenseeeneee 6 7 SCPI commands filters 0 ee ee eeseceeeeeseeceneeceteeenseeenees 6 10 Relative mX b and Percent Range symbols for rel values eee eeeeeeeeeeereeeeeeeeeeeenees 7 3 SCPI commands relative null 2 0 cceceesceeeeeeeeseeeeeees 7 3 SCPI commands mX b and percent eee eeeeeeee 7 6 Buffer SCPI commands buffer 00 ee eee eeceeeseesneceeeeceeeeeneeeeneeees 8 4 9 Table 9 1 Table 9 2 10 Table 10 1 Table 10 2 11 Table 11 1 Table 11 3 Table 11 4 12 Table 12 1 Table 12 2 Table 12 3 13 Table 13 1 Table 13 2 Table 13 3 Table 13 4 Table 13 5 Table 13 6 Table 13 7 14 Table 14 1 15 Table 15 1 16 Table 16 1 Table 16 2 Table 16 3 Triggering Auto delay SEMIN BS sirsenis 9 6 SCPI commands triggering e eeeeeseeeesereerereererrerrersrerrsreee 9 9 Limit Tests Test limit display messages seeseesseeeseeeerrsesrrrrererrereerrreee 10 3 SCPI commands limit tests eee eeeceseeeeeeees 10 12 Full range preamp out values occ ceecceeeesseceneeceeeeeneeeeneees 11 10 SCPI commands external feedback eeseeeeeees 11 17 Remote O peration General bus commands eeeceeeeceeseceeeeceeceneeceneecseeeeneenees 12 8 PC serial port pinout sicaire 12 19 RS 232 connector pinout s eseeesssseesesreerrreerrreereseesreresrerere 12 19 Status Structure Common and SCPI comm
168. e Section 5 for details Input bias current Offset current of Model 6514 is integrated along with the input signal affecting the final reading External voltage source Input current to Model 6514 should be limited to lt ImA Zero check hop Sudden change in the charge reading when zero check is turned off Auto discharge hop Sudden change in the charge reading when auto discharge resets the charge reading to zero 2 20 Measurement Concepts Table 2 6 cont Summary of measurement considerations Considerations Description For all measurements Ground loops Triboelectric effects Piezoelectric and stored charge effects Electrochemical effects Humidity Light Electrostatic interference Magnetic fields Electromagnetic interference EMI See Appendix C for details Multiple ground points can create error signals Charge currents generated in a cable by friction between a conductor and the surrounding insulator i e bending a triax cable Currents generated by mechanical stress on certain insulating materials Currents generated by the formation of chemical batteries on a circuit board caused by ionic contamination Reduces insulation resistance on PC boards and test connection insulators Light sensitive components must be tested in a light free environment Charge induced by bringing a charged object near your test circuit The presence of magnetic fields can generate EMF voltage EMI from ex
169. e calibrator and then press REL pa 18 16 Performance Verification 5 Verify resistance measurement accuracy for the 2kQ 20M ranges as listed in Table 18 5 For each test point e Select the correct Model 6514 measurement range e Set the calibrator resistance to the indicated value e If the calibrator resistance differs from the nominal value recalculate new reading limits based on the resistance and Model 6514 accuracy specifications e Verify that Model 6514 resistance reading is within the required reading limits Table 18 5 2kQ 20MQ range resistance measurement accuracy limits Calibrator Model 6514 ohms reading limits Model 6514 range resistance 1 Year 18 C 28C 2kQ 1 9kQ 1 89610 to 1 90390kQ 20kQ 19kQ 18 9712 to 19 0288kQ 200k amp 2 190kQ 189 522 to 190 478kQ 2MQ 1 9MQ 1 89525 to 1 90475MQ 20MQ 19MQ 18 9617 to 19 0383MQ 1 Nominal resistance values Reading limits based on Model 6514 accuracy specifications and nominal resistance values If actual resistance values differ from nominal values shown recalculate reading limits using actual calibrator resistance values and Model 6514 one year accuracy specifications See Verification limits earlier in this section for details Performance Verification 18 17 200M 2 200G Q range accuracy 1 Connect Model 5156 Electrometer Calibration Standard to Model 6514 as shown in Figure 18 5 Initially connect the BNC shorting cap to the 100MQ r
170. e device requesting service This is necessary for two reasons e Serial polling the Model 6514 causes it to stop asserting the SRQ line e In test systems that have more than one IEEE 488 instrument programmed to assert SRQ your program must determine which instrument is actually requesting service Example Programs E 5 Once an event register has caused a service request it cannot cause another service request until you clear it by reading it in this case using STATus MEASurement EVENt or by send ing the CLS command Storing readings in buffer The reading buffer in the Model 6514 is flexible and capable It has three controls which are found in the TRACe susbsystem There are commands to control e The size of the buffer in readings RACe POINts lt NRf gt Store up to 2000 readings e Where the data is coming from RACe FEED SENSe1 Store unprocessed readings RACe FEED CALCulatel Store CALC1 KMAThH results RACe FEED CALCulate2 Store CALC2 limits readings e Select buffer control mode RACe FEED CONTrol NEVer Immediately stop storing readings RACe FEED CONTrol NEXT Arm buffer stop when buffer is full The following example program sets up the Model 6514 to take 20 readings as fast as it can into the buffer and then reads the data back after the buffer has filled Example program to demonstrate the reading buffer For QuickBASIC 4 5 and CEC PC488 i
171. e for one shot triggering CALL SEND 14 rst status CALL SEND 14 trig sour tlin coun inf status z Take 6514 out of idle ready for external input triggers CALL SEND 14 init status z After the Model 6514 receives the INITiate command it stops at the control source in the trig ger model waiting for a trigger pulse Each time a pulse arrives at the Trigger Link connector the Model 6514 takes one reading Because TRIGger COUNt has been set to INFinity the in strument never enters the idle state You can send the ABORt command to put the instrument in the idle state disabling triggers until another INITiate command is sent E 4 Example Programs Generating SRQ on buffer full When your program must wait until the Model 6514 has completed an operation it is more efficient to program the 6514 to assert the IEEE 488 SRQ line when it is finished rather than repeatedly serial polling the instrument An IEEE 488 controller will typically address the in strument to talk and then unaddress it each time it performs a serial poll Repeated polling of the Model 6514 will generally reduce its overall reading throughput Therefore use the srq func tion call The Model 6514 provides a status bit for almost every operation it performs It can be pro grammed to assert the IEEE 488 SRQ line whenever a status bit becomes true or false The TEEE 488 controller your computer c
172. e is 10 Q or greater 3 10 Volts and Ohms M easurements Input capacitance settling time The settling time of the circuit is particularly important when making volts measurements of a source that has high internal resistance Figure 3 5A or when making high resistance ohms measurements Figure 3 5B In both cases the shunt capacitance C has to fully charge before an accurate voltage mea surement can be made by Vy of Model 6514 The time period for charging the capacitor is deter mined by the RC time constant one time constant t RC and the familiar exponential curve of Figure 3 6 results Therefore it becomes necessary to wait four or five time constants to achieve an accurate reading For example if R 100G and the input cable has a nominal capac itance of 1OpF the RC time constant would be 1 second If 1 accuracy is required a single measurement would require at least five seconds There are two basic ways to minimize this problem 1 keep capacitance in the system to an absolute minimum by keeping connecting cables as short as possible and 2 use guarding There is however a limit to how short the cable can be Using guard can reduce these effects by up to a factor of 1000 see Guarding Input Cable Volts and O hms Measurements 3 11 Figure 3 5 r 4 Hrc 4 Effects of input capacitance E ee G s M easured 6514 Source Voltmeter T RC A High Impedance Volts Measurement U nguarde
173. e of line 4 is LO regardless of the configured clear pattern With the Busy mode selected the clear state of line 4 is HI Limit Tests 10 9 Auto Clear timing The following example timing diagram Figure 10 7 and discussion explain the relationship between the digital output lines for auto clear Figure 10 7 SO T Digital output auto clear timing example Line 1 Line 2 Line 3 Line 4 EOT 10us Delay 10us With the SOT line being pulsed low as shown START TEST must be the selected arm event for the trigger model If the SOT line is instead pulsed high by the handler START TEST must be the selected arm event Initially the four digital output lines are cleared in this case they are all set high Limit tests start when the start of test SOT pulse is received from the component handler When the test ing process is finished the pass or fail pattern is applied to the digital output As shown in the diagram lines 2 3 and 4 go low while line 1 remains high The pulse width delay of the pass fail pattern can be set from 0 to 60 sec 10sec resolution as required by the component handler Note that the delay specifies the pulse width of line 4 The pulse width of lines 1 2 and 3 is actually 20usec longer Line 4 is skewed because it is used as the end of test EOT strobe by category register component handlers Lines 1 2 and 3 establish the bit pattern and then 10sec later the SOT strobe tells
174. ean pressur ized air 11 12 Digital I O Analog O utputs and External Feedback Figure 11 7 e Cre Electrometer input circuitry external Oo o AM gt feedback mode ae A Rep Zero Check a es Pp OpAm S 100M p To Ranging Amplifier Chassis nn Shielded fixture construction Since shielding is so critical for proper operation of external feedback it is recommended that a shielded fixture similar to the one shown in Figure 11 8 be used to house the feedback element The fixture is constructed of a commercially available shielded fixture modified with the stan dard BNC connectors replaced with triaxial female connectors For convenience a banana jack can be mounted on the box to make the necessary preamp out connection Alternately a wire could be run through a rubber grommet mounted in a hole in the side of the box Note that input low is connected to chassis ground within the shielded box This con nection can be made by using a small solder lug secured with a screw Digital 1 0 Analog Outputs and External Feedback 11 13 Non standard coulombs ranges The Model 6514 has four coulombs ranges allowing it to measure charge between 10fC and 20uC Charge measurements greater than 20uC can be obtained by placing the instrument in the external feedback mode and measuring the voltage across an external feedback capacitor See the following subheading External feedback procedur
175. ear command over the bus SRQ You can program the instrument to generate a service request SRQ when one or more errors or conditions occur When this indicator is on a service request has been generated This indicator stays on until the serial poll byte is read or all the conditions that caused SRQ have ceased to exist LOCAL key The LOCAL key cancels the remote state and restores local operation of the instrument Pressing the LOCAL key also turns off the REM indicator and returns the display to normal if a user defined message was displayed If the LLO Local Lockout command is in effect the LOCAL key is also inoperative Remote O peration 12 11 Programming syntax The following paragraphs cover syntax for both common commands and SCPI commands For more information see the IEEE 488 2 and SCPI standards Command words Program messages are made up of one or more command words Commands and command parameters Common commands and SCPI commands may or may not use a parameter The following are some examples SAV lt NRf gt Parameter NRf required RST No parameter used DISPlay ENABle lt b gt Parameter lt b gt required SYSTem PRESet No parameter used Put at least one space between the command word and the parameter e Brackets Some command words are enclosed in brackets These brackets are used to denote an optional command word that does not need to be included in the pro gram messag
176. eceeeeseeeeeeeees 11 13 Logarithmic currents 0 eee ec eeceeeeeeeeeeeeeeeseeseecaeesaeeaee 11 15 Non decade current ais eee eee cee ceeceseeeeeeseeeeeees 11 16 SCPI programming external feedback eee 11 17 Remote O peration Selecting and configuring an interface oes eeeeeeeteeeeeeees 12 2 WMLELE ACES omei on osne eaer E E RE E 12 2 WANS WARES nenene anea E A E ceeds S 12 2 Interface selection and configuration procedures 12 2 GPIB operation and reference 00 ee seecceseeseeeceeeeseeeeeeeeeeneeeees 12 5 GPIB bus Standards gecssescseesserreceseseteesissavsceesccssteescsssssecevesy 12 5 GPIB bus connections 000 eee ee eeeeeeeeeeeeeeeeceesneeseeeaee 12 5 Primary address selection cecceecesseceeeeesseceeeceteeeneeeees 12 7 General bus commands 000 0 eeeeeceecceeseeeeeeeeseceeeneeneeaee 12 8 Front panel GPIB operation eee eeseeeeeeeeeeeeees 12 10 Programming syntax oo eeeeeecsseeeneeceeceeseceeeeeeseeesaeeesees 12 11 RS 232 interface reference oo ee eeesesecteeseeeceeeeeeeceeeeseeeteeenes 12 17 Sending and receiving data ee eee eeeeeeeseeeretseeeaes 12 17 RS 232 settings cc is2sssacvsiesseskcasicespenessiesasesosanscanestancsesacnsbes 12 17 RS 232 COMMECHONS c sccsss cseicssiseseasessiecasnsosoueessescenccesscsaees 12 18 Error MESSALES sei scsssacssdeasssacssteevebstnaresssnsntosscaaeseiecvenstaszee 12 19 13 14 15 16 17 18 Status Structure OVErVIEW peier ie ore a E A E
177. ecify integration rate 0 01 to 10 PLCs 6 0 60Hz 5 0 50Hz CHARge NPLCycles lt n gt Specify integration rate 0 01 to 10 PLCs 6 0 60Hz 5 0 50Hz Programming example rate The following command sets the integration rate for all measurement functions to 2 PLC VOLT NPLC 2 Set integration rate to 2 PLC 6 8 Range U nits Digits Rate and Filters Filters Filtering stabilizes noisy measurements caused by noisy input signals The Model 6514 uses two types of filters median and digital The displayed stored or transmitted reading is simply the result of the filtering processes Note that both the median and digital filters can be in effect at the same time With both filters enabled the median filter operation is performed first After the median filter yields a reading it is sent to the stack of the digital filter Therefore a filtered reading will not be displayed until both filter operations are completed The settings for the filter are global Therefore the filter configuration applies to all four mea surement functions The MEDN key is used to configure and control the median filter and the AVG key is used to configure and control the digital filter When either the median or digital filter is enabled the FILT annunciator is on Median filter The median filter is used to determine the middle most reading from a group of readings that are arranged according to size For example
178. ection 2 Connection Fundamentals WARNING _ A Safety shield is required whenever a hazardous voltage gt 30V is present on the noise shield T his can occur when the test circuit is floated above earth ground at a hazardous voltage level see Floating Measurements in Section 2 C onnections for the safety shield are shown in Figure 4 1 The metal safety shield must completely surround thenoise shield or foating test circuit and it must be connected to safety earth ground using 18 AWG or larger wire NOTE High impedance current measurements require special measurement techniques These connection techniques are covered in High Impedance Measurement Tech niques located in this section 4 4 Amps Measurements Figure 4 1 Red HI Connections for 4 Metal Noise Shield amps lt Metal Safety Shield n Sm Safety Earth 237 ALG 2 round Cabl able WARMNINGINO INTERNAL OPER BLE S SERVICE BY QUALIFIED PERSONNEL ONLY 2 oi KETE ge IEEE 488 PREAMP OUT 2VANALOG COMMON CHASSIS CHANGE IEEE ADDRESS oe 250V PK OUTPUT WITH FRONT PANEL MENU a INPUT 250V PK DIGITAL I O TRIGGER LINK RS232 LINE RATING INPUT PREAMP A 50 60Hz 60 VA MAX lt PREAMP 10K OUT Fuse Line OFF n GUARD 2V ANALOG SUR camer Sanat as 4 V 8 GUARD INPUT COM SB PROGRAMMABLE 315mAT 220 VAC INTERNAL SB 240 VAC CAUTION For CONTINUED PROTECTION AGAINST FIRE HAZARD REP 6514
179. ed in a light free environment While many test fixtures provide adequate light protection others may allow sufficient light penetration to affect the test results Areas to check for light leaks include doors and door hinges tubing entry points and connectors or connector panels Electrostatic interference Electrostatic interference occurs when a electrically charged object is brought near an uncharged object thus inducing a charge on the previously uncharged object Usually effects of such electrostatic action are not noticeable because low impedance levels allow the induced charge to dissipate quickly However the high impedance levels of many measurements do not allow these charges to decay rapidly and erroneous or unstable readings may result These erro neous or unstable readings may be caused in the following ways 1 DC electrostatic field can cause undetected errors or noise in the reading 2 AC electrostatic fields can cause errors by driving the input preamplifier into saturation or through rectification that produces DC errors General M easurement Considerations C 5 Electrostatic interference is first recognizable when hand or body movements near the exper iment cause fluctuations in the reading Pick up from AC fields can also be detected by observ ing the electrometer preamp output on an oscilloscope Line frequency signals on the output are an indication that electrostatic interference is present Means of minimizing
180. ed on Model 6514 accuracy specifications and nominal resistance values If actual resistance values differ from nominal values shown recalculate reading limits using actual standard resistance values and Model 6514 one year accuracy specifications See Verification limits earlier in this section for details 18 18 Performance Verification Coulombs measurement accuracy Follow the steps below to verify that Model 6514 coulombs function measurement accuracy is within specified limits The test involves applying accurate charge values and then verifying that Model 6514 readings are within required limits Figure 18 6 Connections for coulombs verification 1 Input Connect the voltage calibrator and Model 5156 Electrometer Calibration Standard to Model 6514 INPUT jack as shown in Figure 18 6 Be sure to use the charge filter as indicated Initially make connections to the 1nF capacitor and be sure the link between SHIELD and CHASSIS is installed DC Voltage Calibrator come O O ooo Oca oa Connect Cable Shield to Output LO Low noise Coax Cable Change Filter mca Note Connect voltage calibrator Adapter to appropriate capacitor i Oise Be sure shield LO to chassis wO Onm link is connected Triax Cable Model 5156 Calibration Standard Using the GRD key make sure Model 6514 guard mode is disabled Select Model 6514 coulo
181. ed procedure POWER 90 125V or 210 250V 50 60Hz 60VA PHYSICAL Case Dimensions 90mm high x 214mm wide x 369mm deep 3 in x 8 in x 14 in Working Dimensions From front of case to rear including power cord and IEEE 488 connector 15 5 inches Net Weight lt 4 6 kg lt 10 1 lbs Shipping Weight lt 9 5 kg lt 21 lbs Status and Error M essages B 2 Status and Error M essages Table B 1 Status and error messages Number Description Event 440 Query unterminated after indefinite response EE 430 Query deadlocked EE 420 Query unterminated EE 410 Query interrupted EE 363 Input buffer overrun EE 362 Framing error in program message EE 361 Parity error in program message EE 360 Communications error EE 350 Queue overflow SYS 330 Self test failed EE 314 Save recall memory lost EE 315 Configuration memory lost EE 285 Program syntax error EE 284 Program currently running EE 282 Illegal program name EE 281 Cannot create program EE 260 Expression error EE 241 Hardware missing EE 230 Data corrupt or stale EE 225 Out of memory EE 224 Illegal parameter value EE 223 Too much data EE 222 Parameter data out of range EE 221 Settings conflict EE 220 Parameter error EE 215 Arm deadlock EE 214 Trigger deadlock EE 213 Init ignored EE 212 Arm ignored EE 211 Trigger ignored EE 210 Trigger error EE 202 Settings lost due to rtl EE 201 Invalid while in local EE 200 Execution error EE
182. eeeeaes 3 12 AppliGation sitiesicceidiiistincidetli cd aiehieriee alanine aint 3 14 Capacitor dielectric absorption eee eeeeeeecseeeeeeeees 3 14 Amps Measurements Measurement Overview o ee eeeesceceseceeceeeeeeeeeeseeeeaeeeseeseeeaeenaee 4 2 Amps Measurement Procedure ce ee eee cesses eeeeseecseessetaeenaes 4 2 DAM PIN A A A ceiver ieee 4 4 High impedance measurement techniques 0 eee eseeeeee 4 5 SCPI programming ssoi crnog iaei aore eea EEEE SEENA 4 8 Programming example ssssessscsrerceisessisoresssssrcsisrssssrrotevessisis 4 9 Amps measurement Considerations 0 0 eee eeeseecseeeseteeeeees 4 9 Taput bias CULE ss ccsccscsesacsc case caeessssseossseviteenssnceses scdeseossessoes 4 9 Volta PS burden serieei ces cats cause csegsegesestsseuecsers sascocescanstousentoys 4 9 NOISE 5525 ssenseshebinsddscesvdevudneseaiasiveupehbeceaecasvaabovesbabesdacscancepaces 4 10 APP HCALIODS caic asssuidesccacssbsecnsaosesdevensceevsesetesanaseasteezansbancstanesvesees 4 13 Diode leakage current ooo eee eee cee ceecseeeeceseeeeeseeeeeeeees 4 13 Capacitor leakage current 20 0 elec cee ese eeeeteceseeeeeeeeee 4 14 Cable insulation resistance 0 eee ese ceecseesecneeeeeeeees 4 14 Surface insulation resistance SIR cccccseeesecesseeseeeeees 4 15 Coulombs Measurements Measurement OVerviewW o eee eeececeeeceeeeeeeeeeeeeecaeeseecaeeaetaeenaee 5 2 AULO discharge se 52555ccctatsceactesstavsacecestssihecsdscsaabeasnsscnest
183. eeeseseseseseceeeecesececeeeeeeecs H 4 Getting Started General information Covers general information that includes warranty informa tion contact information safety symbols and terms inspection and available options and accessories System electrometer features Summarizes the features of Model 6514 Front and rear panel familiarization Summarizes the controls and connectors of the instrument Power up Covers line power connection line voltage setting fuse replacement power line frequency and the power up sequence Display Provides information about the display of Model 6514 Default settings Covers the five instrument setup configurations available to the user three user defined GPIB defaults or factory defaults SCPI programming Explains how SCPI commands are presented in this manual 1 2 Getting Started General information Warranty information Warranty information is located at the front of this manual Should your Model 6514 require warranty service contact the Keithley representative or authorized repair facility in your area for further information When returning the instrument for repair be sure to fill out and include the service form at the back of this manual to provide the repair facility with the necessary information Contact information Worldwide phone numbers are listed at the front of this manual If you have any questions please contact your local Keithley
184. ely AUTO lt b gt When enabled I O port clears when INITiate ON sent PASS Define pass digital output pattern SOURce2 lt NDN gt or lt NRf gt Specify 4 bit pass pattern no failures 15 B NULL Configure and control Rel Sec 7 OFFSet lt NRf gt Specify Rel value 9 999999e20 to 9 999999e20 0 0 STATe lt b gt Enable or disable Rel OFF DATA Return CALC2 reading s triggered by INITiate D LATest Return last latest CALC2 reading D Limit Tests 10 13 Table 10 2 cont SCPI commands limit tests Command Description Default Ref SOURce2 SOURce2 Subsystem TTL lt NDN gt or lt NRf gt Specify 4 bit digital output clear pattern 15 B CLEar Clear I O port return output to TTL pattern IMMediate Clear I O port immediately AUTO lt b gt Enable or disable auto clear OFF DELay lt n gt Specify delay pulse width for pass fail 0 0001 pattern 0 to 60 sec TTL4 Line 4 Mode configuration MODE lt name gt Select output line 4 mode EOTest or BUSY EOT BSTate lt ttl gt Select active TTL level for busy 1 HI or 0 LO 0 Trigger Subystem Sec 9 ARM Arm Layer SOURce lt name gt Select control source NSTest PSTest or IMMediate IMM E INITiate Initiation one trigger cycle D FORMat FORMat subsystem SOURce2 lt name gt Select data format for reading output patterns ASC lt name gt ASCii Decimal format HEXadecimal Hexadecimal format OCTal Octal format
185. em PRESet and STATus PRESet have no effect on the error queue A SYSTem PRESet DISPlay FO RMat and SYSTem Returns the instrument to states optimized for front panel operation SYSTem PRESet defaults are listed in the SCPI tables in Section 17 B SY STem TIME RESet Resets the absolute timestamp to 0 seconds The timestamp also resets when power is cycled or after the instrument is on for 99 999 99 seconds The TRACe TSTamp FORMat command is used to select the absolute timestamp See Section 8 Buffer for details C SYSTem PO Setup lt name gt Parameters RST PRESet SAVx Power up to RST defaults Power up to SYSTem PRESet defaults Power up to setup stored in memory x memory location 0 1 2 3 or 4 16 9 The RST and SYSTem DEFaults are listed in the SCPI tables in the Section 17 A setup is saved in memory using the SAV command See Section 14 Common Commands for details D SYSTem VERSion Read the version of the SCPI standard being used by Model 6514 Example response mes sage 1996 0 E SYSTem KEY lt NRf gt Parameters 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 SHIFT key V key Ikey Q key Q key XFDBK key ZCHECK key ZCOR key RANGE up arrow key AUTO key RANGE down arrow key ENTER key Cursor right arrow key GRD key 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 LOCAL key AVG key MEDIAN key REL key LIMIT key DIGIT key RATE key
186. end OPC C SAV lt NRf gt save Save present setup in memory RCL lt NRf gt recall Return to setup stored in memory Parameters 0 Memory location 0 1 Memory location 1 2 Memory location 2 Use the SAV command to save the present instrument setup configuration in memory for later recall Any control affected by RST can be saved by the SAV command The RCL com mand is used to restore the instrument to the saved setup configuration Three setup configura tions can be saved and recalled Model 6514 ships from the factory with SYSTem PRESet defaults loaded into the available setup memory If a recall error occurs the setup memory defaults to the SYSTem PRESet values Programming example SAV 2 Save present setup in memory location 2 RST Set 6514 to RST defaults RCL 2 Return recall 6514 to setup stored in memory location 2 D RST reset Return Model 6514 to RST defaults When the RST command is sent Model 6514 performs the following operations 1 Returns Model 6514 to the RST default conditions see Default column of SCPI tables 2 Cancels all pending commands 3 Cancels response to any previously received OPC and OPC commands 14 4 Common Commands E TRG trigger Send bus trigger to Model 6514 Use the TRG command to issue a GPIB trigger to Model 6514 It has the same effect as a group execute trigger GET Use the TRG command as an event to control operation Model 6514 reac
187. ent i B15 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 BO Condition Register event status yY Y l l yY yY l y LEVEN BFL BAV ROF RAV LP HL2F LL2F HL1F LLIF Measurement B15 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 Bo Event Register _ To MSB bit i of Status Byte OR Fe amp Register E C ja amp m ENABLe lt NRf gt BFL BAV ROF RAV LP HL2F LL2F HL1F LLIF Measurement Event ENABLe B15 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 Enable Register Decimal 512 256 128 64 32 16 8 4 2 Weights 2 28 27 2 25 24 23 23 24 BFL Buffer Full HL2F High Limit 2 Fail amp Logical AND BAV Buffer Available LL2F Low Limit 2 Fail OR Logical OR ROF Reading O verflow HLIF High Limit 1 Fail RAV Reading Available LL1F Low Limit 1 Fail LP Limits Pass Status Structure 13 15 Questionable event status The used bits of the questionable event register shown in Figure 13 7 are described as follows Bit B7 calibration summary Cal Set bit indicates that an invalid calibration con stant was detected during the power up sequence This error will clear after successful calibration of Model 6514 BitB14 command warning Warn Set bit indicate
188. ent register that caused the first SRQ has not been cleared The serial poll does not clear MSS The MSS bit stays set until all status byte summary bits are reset SPE SPD serial polling The SPE SPD general bus command is used to serial poll Model 6514 Serial polling obtains the serial poll byte status byte Typically serial polling is used by the controller to determine which of several instruments has requested service with the SRQ line byte and service request commands The commands to program and read the status byte register and service request enable regis ter are listed in Table 13 3 For details on programming and reading registers see Programming enable registers and Reading registers NOTE To reset the bits of the service request enable register to 0 use 0 as the parameter value for the SRE command i e SRE 0 Table 13 3 Common commands status byte and service request enable registers Command Description Default STB Read status byte register SRE lt NDN gt or lt NRf gt Program the service request enable register Note lt NDN gt Bxx x Binary format each x 1 or 0 Hx Hexadecimal format x 0 to FF Qx Octal format x 0 to 377 lt NRf gt 0to 255 Decimal format SRE Read the service request enable register Note CLS and STATus PRESet have no effect on the service request enable register 13 10 Status Structure Programming example set MSS
189. er NOTE SYSTem PRESet and RST have no effect on status structure registers and queues Table 13 1 Common and SCPI commands reset registers and clear queues Commands Description Ref To reset registers CLS Reset all bits of the following event registers to 0 Note 1 Standard event register Operation event register Measurement event register Questionable event register STATus STATus subsystem PRESet Reset all bits of the following enable registers to0 Note 1 Operation event enable register Measurement event enable register Questionable event enable register To clear error queue CLS Clear all messages from error queue Note 2 STATus STATus subsystem QUEue Error queue CLEar Clear messages from error queue Note 3 SYSTem SYSTem subsystem ERRor Error queue CLEar Clear messages from error queue Note 3 Notes 1 The standard event enable register is not reset by STATus PRESet or CLS Send the 0 parameter value with ESE to reset all bits of that enable register to 0 see Status Byte and Service Request commands 2 STATus PRESet has no effect on the error queue 3 Use either of the two clear commands to clear the error queue Status Structure 13 5 Programming and reading registers Programming enable registers The only registers that can be programmed by the user are the enable registers All other reg isters in the status structure are read only registers The following
190. er The individual bits of the service request enable register can be set or cleared by using the SRE common command To read the service request enable register use the SRE query com mand The service request enable register clears when power is cycled or a parameter value of 0 is sent with the SRE command i e SRE 0 The commands to program and read the SRQ enable register are listed in Table 13 6 Serial Status Status Structure 13 9 polling and SRQ Any enabled event summary bit that goes from 0 to 1 will set bit B6 and generate an SRQ service request In your test program you can periodically read the status byte to check if an SRQ has occurred and what caused it If an SRQ occurs the program can for example branch to an appropriate subroutine that will service the request Typically SRQs are managed by the serial poll sequence of Model 6514 If an SRQ does not occur bit B6 RQS of the status byte register will remain cleared and the program will simply proceed normally after the serial poll is performed If an SRQ does occur bit B6 of the status byte register will set and the program can branch to a service subroutine when the SRQ is detected by the serial poll The serial poll automatically resets RQS of the status byte register This allows subsequent serial polls to monitor bit B6 for an SRQ occurrence generated by other event types After a serial poll the same event can cause another SRQ even if the ev
191. er type is used to send decimal values and does not use a header The following examples show the proper parameter syntax to set an output pattern to 1101 lines 4 3 and 1 set HI b1101 Binary format lt NDN gt parameter type hD Hexadecimal format lt NDN gt parameter type q15 Octal format lt NDN gt parameter type 13 Decimal format lt NRf gt parameter type NOTE When a query command to read a programmed output pattern i e CALC2 LIM UPP SOUR2 is sent the format for the returned value is deter mined by the presently selected response message format for output patterns see FORMat SOURce2 command in Table 10 2 C FAIL In the event of a failure you can read the measurement event register to determine which limit upper or lower failed See Section 13 to program and read the measurement event register D DATA The INITiate command must be sent to perform the programmed number of measurements If the instrument is programmed to perform a finite number of measurements the DATA com mand will return all the CALC2 readings after the last reading is taken The DATA LATest command will only return the last latest CALC2 reading If the instrument is programmed to perform an infinite number of measurements arm count or trigger count set to infinite you cannot use the DATA command to return CALC2 readings However you can use the DATA LATest command to return the last CALC2 reading after aborting the me
192. er 0 UTPut gt SENSe NONE TRIG ger D ELay AUTO lt b gt Trigger Delay 0 0 sec MEASURE Action Note The following commands place the Model 6514 into GPIB Default idle ABO Rt RST SYSTem PRESet RCL lt NRf gt Output Trigger DCL and SDC The only difference between front panel operation Figure 9 1 and remote operation Figure 9 2 is within the idle state of the instrument Nomenclature in Figure 9 1 relates to the various names used for configuration menu items while Figure 9 2 provides the SCPI commands to control operation 9 4 Triggering Idle and initiate While in the idle state the instrument cannot perform measurements While in idle the read ing remains frozen or dashes replace the reading i e V Once Model 6514 is taken out of idle operation proceeds through the trigger model Front panel operation As shown in Figure 9 1 Model 6514 immediately leaves the idle state when it is turned on Typically operation remains in the arm and trigger layers of the trigger model However Model 6514 can be put into the idle state at any time by pressing the HALT key To take the instrument out of idle press the TRIG key Other front panel keys can instead be pressed but they may change the setup Remote operation As shown in Figure 9 2 an initiate command is required to take the instrument out of idle The following commands perform an initiate operation e INITiate e READ e ME
193. ereeeeeeneesaes 18 9 Input bias current calibration 0 eee eee ee eeeeeeeeeeeeneeeees 18 9 Volts measurement ACCULACY oo ee eeeeeecseeeteeeeseceeeeseeneeesees 18 10 Amps measurement ACCULACY eee eects eeeeeeeeeeeseeeetaeeaes 18 12 2OUA 20MA range ACCULACY oo eee csesecseesseceeeteeeeees 18 12 2OpA 2UA range ACCULACY oes eee eeeeee cesses ceeeteceseeeeeeeees 18 13 Ohms measurement accuracy 0 eee cece eeeeeeeeeeeeeseeeseesaeeaee 18 15 2kQ 20MQ range ACCULaCY 0 eee eect cess eeeeeeeeeeeeeeeeeeens 18 15 200M22 200GQ2 range accuracy oo eee eee eseseeeeeseeeaee 18 17 Coulombs measurement accuracy ee eeeeeeeeeeeeeseeeneeseeeaes 18 18 Calibration IntrOductOny css cssuszssscesbesesssvacscssepstiasssbecestietavsessassseesansaeuicsveashs 19 2 Environmental Conditions 20 0 0 ce eeeeceseeeeceeceeeceeeeeeeeeeeeetees 19 2 Temperature and relative humidity ee eee eee 19 2 Warm Up Period 0 eeeeceeeeceseeeeeceeeeecaeeaeceesaecneenaeeneees 19 2 Line POWER sesssciei ses ocevesstins coats Eea E EEEE EE SEa 19 2 Calibration considerations seesseesseeeeesrrerserererreserrssrrrrsrrersee 19 3 Calibration Cycle ccccccscsseesseseseeesssesseecseendsoeseeveneossesboesess 19 3 Recommended calibration equipment esesesesseerseeerrererrereeee 19 3 Calibration errors oo cece ceeceseceeceseeeeceseeeeeeeeeeeeeeeeeeseneeeeeens 19 5 Calibration Menu oo eee cee ceseceeceseeeeeeseeeeeeeeeeeeeeeseeseaeeeaeens 19 5 Aborting Calibrat
194. erform zero correction volts only To achieve optimum accuracy for low voltage measurements it is recommended that you zero correct the electrometer To do so select the 2V range which is the lowest range and press the ZCOR key until the ZZ message is displayed See Section 2 for details on zero correction Step 4 Select a manual measurement range or enable auto range Use the RANGE 4 and y keys to select a manual measurement range or press AUTO to enable auto range With auto range enabled the instrument will automatically go to the most sensitive range to make the measurement See Section 6 for details on range Volts and O hms Measurements 3 5 Step 5 Connect the D UT to the electrometer NOTE Fundamental information on making connections to the electrometer input is pro vided in Section 2 Connection Fundamentals WARNING A metal safety shield is required whenever a hazardous voltage gt 30V is present on a noise shield or guard shield As shown in Figures 3 2 and 3 3 the safety shield must be connected to safety earth ground using 18 AWG wire or larger U nguarded connections Connections for unguarded volts and ohms measurements are shown in Figure 3 2 where the DUT is the voltage or resistance to be measured If a hazardous voltage gt 30V is present on the noise shield or the test circuit is floating above earth ground at a hazardous voltage level a safety shield must be used as shown Figure 3
195. ers and line 1 is selected for input triggers These input output assignments can be changed as previously explained in this section The connector pinout is shown in Figure 9 4 Figure 9 4 Rear Panel Pinout Pin Number Description Trigger link connection 1 Trigger Link 1 operation DO 2 Trigger Link 2 oO 3 Trigger Link 3 QM 4 Trigger Link 4 5 Trigger Link 5 Trigger Link gger 6 Trigger Link 6 J Ground 8 Ground Input trigger requirements An input trigger is used to satisfy event detection for a trigger model layer that is using the TLINK control source The input requires a falling edge TTL compatible pulse with the speci fications shown in Figure 9 5 Figure 9 5 Trigger link input Triggers A pulse specifications Leading Edge TTL High 2V 5V TTL Low lt 0 8V 10us Minimum 9 12 Triggering Output trigger specifications Model 6514 can be programmed to output a trigger immediately after a measurement and or when operation leaves the trigger layer of the trigger model The output trigger provides a TTL compatible output pulse that can be used to trigger other instruments The specifications for this trigger pulse are shown in Figure 9 6 A trigger link line can source 1mA and sink up to 50mA Figure 9 6 Trigger link output 88 2 pu Meter pulse specifications Complete TTL High 3 4V Typical TTL Low 0 25V Typical 10us Minimum External trigger example In a simple test system you m
196. es and non standard charge ranges Remote interface Model 6514 can be controlled using the IEEE 488 interface GPIB or the RS 232 interface GPIB programming language When using the GPIB the instrument can be pro grammed using the SCPI or DDC programming language Getting Started 1 5 Front and rear panel familiarization Front panel summary Figure 1 1 Model 6514 front panel 4 The front panel of Model 6514 is shown in Figure 1 1 NOTE KEITHLEY RS 232 MXB VAL CONFLM UNITS NPLC AVG J MEDN REL LIMIT DIGIT RATE CHED JEST CAL A EIUP CONE ABM CONE TAIG Q STORE RCLL DELAY DAMP HALT TRIG EXIT JENTER Most keys provide a dual function or operation The nomenclature on a key indicates its unshifted function operation which is selected by pressing the key Nomenclature in blue above a key indicates its shifted function A shifted function is selected by pressing the SHIFT key and then the function operation key 1 Special keys and power switch SHIFT Use to select a shifted function or operation LOCAL Cancels GPIB remote mode POWER Power switch In position turns 6514 on I out position turns it off O 2 Function and operation keys Top Row Unshifted V Selects voltage measurement function Selects current measurement function Q Selects resistance measurement function Q Selects charge measurement function XFBK Enables disables External Feedback ZCHK Enables
197. es data Depending on the type of instrument any particular device can be a talker only a listener only or both a talker and listener There are two categories of controllers system controller and basic controller Both are able to control other instruments but only the system controller has the absolute authority in the sys tem In a system with more than one controller only one controller may be active at any given time Certain protocol is used to pass control from one controller to another The IEEE 488 bus is limited to 15 devices including the controller Thus any number of talk ers and listeners up to that limit may be present on the bus at one time Although several devices may be commanded to listen simultaneously the bus can have only one active talker or commu nications would be scrambled A device is placed in the talk or listen state by sending an appropriate talk or listen command These talk and listen commands are derived from an instrument s primary address The primary address may have any value between 0 and 31 and is generally set by rear panel DIP switches or programmed in from the front panel of the instrument The actual listen address value sent out over the bus is obtained by ORing the primary address with 20 For example if the primary address is 14 the actual listen address is 34 34 14 20 In a similar manner the talk address is obtained by ORing the primary address with 40 With the present exa
198. esensvsessuenecbeteesseets 16 4 SYSTEM SUDSYStOMy vin ssculscdecsascsseesscssacnsachdes ances coumpsnsvecnsceveseeaees 16 8 SCPI Reference Tables General Totes ecserin aa aeS REER 17 2 Performance Verification Tntrodutti on sennecese ei a uE e aE R 18 2 Verification test requirements sessessseeesseesesesrreesreersreersreeees 18 3 Environmental Conditions essesesesseeeseeerreerrereererrsreersreee 18 3 Warm up Perl cov sisnsciicdacsisectenndsdsceuscssesedeactessevacdsad cusses 18 3 LIME POWER socssicscesscesstensisscteversesv savesaausizecosatessgavsestueessnsates 18 3 Recommended test equipment 0 eee eee cee eecseeeseenaeeeeens 18 4 Verification IMIS nsss sesaran eao ena e E rs ERa 18 6 Example reading limits calculation cesses ees 18 6 Recalculating resistance reading limits 0 00 eee 18 6 Calibrator voltage calculations 0 eee eeceeseeeeeeeeeeeeeeseeeee 18 7 Current calculations i icc sc sciscasaisas anes ateseseneasevacnstevecescees 18 7 Charge calculations ccccecesesseesceseseeseeesenecseseeeeeeneseees 18 7 19 Performing the verification test procedures ss seeeeeeeeeees 18 8 Test Summary osc hte aii anki 18 8 Test considerations 4 i iicniiniiiieladuiseinkatienis 18 8 Restoring factory defaults ce eeeeceeceseeseeeceecssetereeeeeseeeees 18 9 Input bias current and offset voltage calibration 18 9 Offset voltage calibration eee ceeeeeeeeeeee
199. esistance jack Be sure to remove the link between SHIELD and CHASSIS and connect Model 5156 CHASSIS jack to Model 6514 COMMON terminal WARNING Hazardous voltage may be present on Model 5156 SHIELD and OUTPUT jacks Figure 18 5 Model 5156 Calibration Standard Model 6514 Electrometer Connections for ohms 5 verification 200MQ MEO Oira 200GQ ranges BUD n A 100nF Remove SHIELD to CHASSIS link To Shield Connect SHIELD to 6514 COMMON Triax Cable Note Enable guard mode 2 Select Model 6514 ohms function with the Q key Using the GRD key enable Model 6514 guard mode 4 Verify resistance measurement accuracy for the 200MQ 200GQ ranges as listed in Table 18 6 For each test point e Select the correct Model 6514 measurement range e Connect the BNC shorting cap to select the appropriate standard resistor e If the standard resistance differs from the nominal value recalculate new reading limits based on the resistance and Model 6514 accuracy specifications e Verify that Model 6514 resistance reading is within the required reading limits R Table 18 6 200M 92 200GQ resistance measurement accuracy limits Mode 6514 ohms reading limits Model 6514 range Standard resistance 1 Year 18 C 28 C 2 200MQ 100M 99 697 to 100 303MQ 2GQ 1GQ 0 98496 to 1 01504GQ 20GQ 10GQ 9 8497 to 10 1503GQ 200GQ 100GQ 98 497 to 101 503GQ l Nominal resistance values 2 Reading limits bas
200. est over GPIB STAT Displaying buffer statistics TALK Instrument addressed to talk over GPIB bus TIM ER Timer controlled triggering in use TRIG External triggering GPIB or trigger link selected 5 Handle Pull out and rotate to desired position 1 8 Getting Started Rear panel summary The rear panel of Model 6514 is shown in Figure 1 2 Figure 1 2 Model 6514 rear panel 5 SERVICE BY QUALIFIED PERSONNEL ONLY MADE IN USA PREAMP OUT 2V ANALOG COMMON CHASSIS 250V PK OUTPUT INPUT 250V PK DIGITAL I O TRIGGER LINK LINE RATING 50 60Hz 60 VA MAX 630mAT 100 VAC SB 120 VAC 315mAT 220 VAC SB 240 VAC ON AGAINST AIRI ST FIF INPUT PREAMP Opry ON me iT F FOLLOWS V GUARD INPUT PROGRAMMABLE PREAMP OUT 2V ANALOG OUTPUT COM INTERNAL CAUTION For continuen PROTEC HON AS 1 INPUT This standard 3 lug female triax connector is used to connect the signal to be measured to the input of Model 6514 Mates to a triax cable terminated with a 3 lug male triax connector 2 PREAMP OUT Provides a guard output for Volts measurements Can be used as an inverting output or with external feedback for the Amps and Coulombs modes 3 2V ANALOG OUTPUT Provides a scaled DC output voltage A full range input will result in a 2V analog output For the volts function the output is non inverting 4 COMMON Use as input low or the commo
201. eter only measures Ip Figure 4 2 High impedance current measurements Ru E r3 8 BE Metal Mounting Plate l Insulators _ A Unguarded Im Ip IR gt gt NNA O con Aid l 6514 L ZE 2 gt gt T Metal Guard Plate i VW N R gt 1GQ B G uarded 4 6 Amps Measurements Floating current measurements As discussed in Section 3 for volts measurements guarding uses a conductor at essentially the same potential as input HI to drastically reduce leak age currents in high impedance test circuits No current can flow when there is a OV drop across a leakage resistance For floating current measurements ammeter input LO can be used as the guard since it totally surrounds input HI via the input triax cable and is at nearly the same potential as input HI The actual voltage drop known as voltage burden depends on which measurement range is being used The voltage burden values are listed in the specifications Appendix A Figure 4 3A shows an unguarded floating current measurement in a high impedance circuit The goal is to measure the current Ip through resistor R However a leakage path R exists from ammeter input LO to test circuit common Since the ammeter drops essentially OV approx imately 10V is dropped by R The current through R will be approximately 10nA 10V 1GQ 10nA Therefore the current that is measured by Model 6514 is
202. ets EE 815 Too many parentheses EE 816 Entire expression not parsed EE 817 Unknown token EE 818 Error parsing mantissa EE 819 Error parsing exponent EE 820 Error parsing value EE 821 Invalid data handle index EE 830 Invalid with INFinite ARM COUNT EE 831 Invalid with INFinite TRIG COUNT EE 900 Internal system error EE DDC Status Model 950 Rdg overflow SE 951 Rdg ready SE 952 Buffer full SE 953 IDDC error EE 954 IDDCO error EE 955 Trig overrun EE 956 No remote EE 957 Number error EE 958 DDC ready SE 960 DDC Mode IDDC Error EE 961 DDC Mode IDDCO Error EE B 5 B 6 Status and Error M essages Table B 1 cont Status and error messages Number Description Event Keithley 6512 Serial Poll Byte Events 962 DDC Ready SE 963 DDC Reading Done SE 965 DDC Buffer Full SE 966 DDC Reading overflow SE EE error event SE status event SYS system error event NOTE Errors and status messages with a positive number are instrument dependent Negative errors are reserved by SCPI NOTE SCPI confirmed messages are described in Volume 2 Command Reference of the Standard Commands for Programmable Instruments Refer to the SYSTem ERRor command General M easurement Considerations C 2 General M easurement Considerations Measurement considerations The following measurement considerations apply to all precision measurements Measure ment considerations that are uni
203. etting is then displayed To retain the displayed flow control setting FLOW press ENTER To change the flow control setting a Press lt orp to move the cursor over to the flow control setting b Use A or w to display the desired flow control setting NONE or XonXoff c Press ENTER NOTE Only the SCPI language can be used with the RS 232 interface The instrument defaults to the SCPI language when the RS 232 interface is selected enabled Remote O peration 12 5 GPIB operation and reference GPIB bus standards The GPIB bus is the IEEE 488 instrumentation data bus with hardware and programming standards originally adopted by the IEEE Institute of Electrical and Electronic Engineers in 1975 Model 6514 conforms to these standards e JEEE 488 1 1987 JTEEE 488 2 1992 This standard defines a syntax for sending data to and from instruments how an instrument interprets this data what registers should exist to record the state of the instrument and a group of common commands e SCPI 1996 0 Standard Commands for Programmable Instruments This standard defines a command language protocol It goes one step further than TEEE 488 2 1992 and defines a standard set of commands to control every programmable aspect of an instrument GPIB bus connections To connect Model 6514 to the GPIB bus use a cable equipped with standard IEEE 488 con nectors as shown in Figure 12 1 Figure 12 1 IEEE 488 connector
204. etween input HI and input LO This leakage resistance and capacitance could adversely affect high impedance measurements Test circuit leakage In a test circuit leakage current can occur through the insulators of the terminals for the DUT device under test In Figure 3 1 the test circuit consists of a current source in series with the DUT The objective is to make an accurate voltage measurement of the DUT In Figure 3 1A a resistance leakage path through the insulators RL1 and RL2 shunts cur rent around the DUT If this leakage current is high in comparison to the DUT current signifi cant measurement error will occur To keep error lt 0 1 the leakage resistance must be 1000 times greater than the resistance of the DUT For example if the nominal resistance of the DUT is 1OOMQ leakage resistance must be gt 100GQ Figure 3 1B shows how to use guarding to eliminate the effects of leakage resistance With GRD enabled the driven guard which is at the same potential as input HI is connected to the metal mounting plate now known as the guard plate With both ends of RL1 at the same poten tial current will not flow through the insulator With no current leakage path all current flows through the DUT allowing an accurate voltage measurement The above explanation also pertains to ohms measurements The only difference is that the test current is provided by Model 6514 Volts and O hms Measurements 3 3
205. explains how to ascertain the parameter values for the various commands used to program enable registers The actual com mands are covered later in this section see Tables 13 3 and 13 6 A command to program an event enable register is sent with a parameter value that deter mines the desired state 0 or 1 of each bit in the appropriate register An enable register can be programmed using any of the following data formats for the parameter value binary decimal hexadecimal or octal The bit positions of the register see Figure 13 2 indicate the binary parameter value For example if you wish to sets bits B4 B3 and B1 the binary value would be 11010 where B4 1 B3 1 B1 1 and all other bits are 0 When you use one of the other formats convert the binary number to its decimal hexadecimal or octal equivalent Binary 11010 Decimal 26 Hexadecimal 1A Octal 32 Note that Figure 13 2 includes the decimal weight for each register bit To set bits B4 B3 and B1 the decimal parameter value would be the sum of the decimal weights for those bits 16 8 2 26 The lt NDN gt non decimal numeric parameter type is used to send non decimal values These values require a header B H or Q to identify the data format being sent The letter in the header can be upper or lower case The lt NRf gt numeric representation format parameter type is used to send decimal values and does not use a header The following examples show the pr
206. g Model 6514 to talk after the appro priate query is sent Status Structure 13 19 Error queue The error queue holds error and status messages When an error or status event occurs a mes sage that defines the error status is placed in the error queue When a message is placed in the error queue the error available EAV bit in the status byte register is set An error status message is cleared from the error queue when it is read The error queue is considered cleared when it is empty An empty error queue clears the EAV bit in the status byte register The error queue holds up to 10 error status messages The commands to read the error queue are listed in Table 13 7 When you read a single message in the error queue the oldest message is read and then removed from the queue If the queue becomes full the message 350 queue overflow will occupy the last memory location On power up the error queue is empty When empty the message 0 No Error is placed in the queue Messages in the error queue are preceded by a code number Negative numbers are used for SCPI defined messages and positive numbers are used for Keithley defined messages The messages are listed in Appendix B As shown in Table 13 7 there are commands to read the entire message code and message or the code only On power up all error messages are enabled and will go into the error queue as they occur Status messages are not enabled a
207. g language setting is then displayed To retain the displayed programming language LANG press ENTER To change the programming language a Press lt or to move the cursor over to the language setting b Press a or y to display the desired language setting SCPI or DDC c Press ENTER The unit will reset RS 232 interface The RS 232 interface is selected and configured from the RS 232 menu structure From this menu you can enable or disable the RS 232 interface and check or change the following settings Baud rate 57 6K 38 4k 19 2k 9600 4800 2400 1200 600 or 300 Data bits 7 or 8 Parity none odd or even Terminator CR LF CRLF or LFCR Flow control none or Xon Xoff 12 4 Remote O peration NOTE See RS 232 Interface Reference located at the end of this section for information on these settings and connections to the computer Selecting R S 232 interface Press SHIFT and then RS 232 to access the RS 232 menu The present status on or off of the RS 232 interface is displayed If it is already enabled on proceed to step 1 of Checking Changing RS 232 Settings to check and or change the settings Perform the following steps to enable select the RS 232 interface 1 Place the cursor on the OFF setting by pressing the lt or p key Press the a or w key to toggle the setting to ON Press ENTER The instrument will exit the menu structure and perform the power on sequence
208. ges in queue CODE Code numbers only NEXT Read and clear oldest error status code only ALL Read and clear all errors status codes only CLEar Clear messages from error queue Sec 13 KEY lt NRf gt Simulate key press see Figure 16 3 vV KEY Query the last pressed key vV 17 12 SCPI Reference Tables Table 17 7 cont SYSTem command summary Default Command Description parameter Ref SCPI RS 232 interface Sec 12 LOCal Take Model 6514 out of remote RS 232 only REMote Put Model 6514 in remote RS 232 only RWLock Enable or disable local lockout RS 232 only Note Clearing the error queue Power up and CLS clears the error queue RST SYSTem PRESet and STATus PRESet have no effect on the error queue Table 17 8 TRACe command summary Default Command Description parameter Ref SCPI TRACel DATA Use TRACe or DATA as root command see Note Sec 8 Vv DATA Read the contents of the buffer data store Vv CLEar Clear readings from buffer FREE Query bytes available and bytes in use vV POINts lt n gt Specify size of buffer 1 to 2500 100 vV ACTual Query number of readings stored in buffer POINts Query buffer size V FEED lt name gt Select source of readings for buffer SENSe 1 SENS1 Vv CALCulate 1 or CALCulate2 CONTrol lt name gt Select buffer control mode NEXT or NEVer NEV Vv CONTrol Query buffer control mode v
209. gnetic compatibility EMC requirements of the European Union as denoted by the CE mark However it is still possible for sensitive measurements to be affected by external sources In these instances special precautions may be required in the measurement setup Sources of EMI include e Radio and TV broadcast transmitters e Communications transmitters including cellular phones and handheld radios e Devices incorporating microprocessors and high speed digital circuits e Impulses sources as in the case of arcing in high voltage environments The effect on instrument performance can be considerable if enough of the unwanted signal is present The effects of EMI can be seen as an unusually large offset or in the case of impulse sources erratic variations in the displayed reading C 6 General M easurement Considerations The instrument and experiment should be kept as far away as possible from any EMI sources Additional shielding of the instrument experiment and test leads will often reduce EMI to an acceptable level In extreme cases a specially constructed screen room may be required to suf ficiently attenuate the troublesome signal External filtering of the input signal path may be required In some cases a simple one pole filter may be sufficient In more difficult situations multiple notch or band stop filters tuned to the offending frequency range may be required Connecting multiple capacitors of widely dif ferent values
210. guration menu The configuration menu for limits is structured as follows Bullets denote the main items of the menu To access the menu press SHIFT and then CONF LIM e LIMIT 1 Configure limit 1 test CONTROL Enable or disable limit 1 test HILIM Set the HI limit 9 999999T to 9 999999T and set the fail digital out put bit pattern 0 to 15 LOLIM Set the LO limit 9 999999T to 9 999999T and set the fail digital output bit pattern 0 to 15 e LIMIT 2 Configure limit 2 test CONTROL Enable or disable limit 2 test HILIM Set the HI limit 9 999999T to 9 999999T and set the fail digital out put bit pattern 0 to 15 LOLIM Set the LO limit 9 999999T to 9 999999T and set the fail digital output bit pattern 0 to 15 e PASS Set the digital output bit pattern for the all tests pass condition 0 to 15 e DIG CLR Digital Clear AUTO CLR Enable or disable auto clear for the digital output DEL Delay Set the pass fail pattern pulse width 0 to 60 sec with 10usec resolu tion DIGOUT Set the digital output clear pattern 0 to 15 Limit Tests 10 11 e LIN4MOD Line 4 Mode ENDOFTST End of Test With this mode Model 6514 will pulse the EOT line when the test is finished Use with catagory register component handlers BUSY and BUSY Pulls line 4 LO Busy or HI Busy while the test is in pro cess Use with catagory pulse component
211. gure 13 5 Figure 13 6 Figure 13 7 16 Figure 16 1 Figure 16 2 Figure 16 3 18 Figure 18 1 Figure 18 2 Figure 18 3 Figure 18 4 Figure 18 5 Figure 18 6 19 Figure 19 1 Figure 19 2 Figure 19 3 Figure 19 4 Figure 19 5 Figure 19 6 20 Figure 20 1 Remote O peration TEEE 488 connector cccccessscecsssecesecceceesececsseeeesseeeensaeees 12 5 TEEE 488 connections cccececcecesseceseececeeeeeceseeeesseeeensaeees 12 6 TEEE 488 connector location ccccecceceesscecsseeeeeseeeeesneees 12 7 RS 232 interface connector cecsececeseceesececsceeeeseeeensees 12 18 Status Structure 6514 status mode structure 2 0 ee ceececessececeseeeeseeceeesneeeeenaes 13 3 16 bit stat s TEGISLEL scscessicssissescesssesdesseneseasctersssssscseastsenssonases 13 6 Status byte and service request 2 0 0 cece eect eeeeeeeeeeeeeeeeeeeees 13 7 Standard event Status ccccsecessseeesececeeseeeceseecessseeeseaeees 13 12 Operation event Status oe eeeeceeeeeeeeseeeeeceeeaeeseeeaes 13 13 Measurement event status c ecccceceseecessecessneeeseeeeeenes 13 14 Questionable event Status cccccceseseceeseceseseeeesseeeeeees 13 15 DISPlay FO RMat and SYSTem ASCII data format ccccccccscccssecscecsecesseeseeeesseeeseeeseeenees 16 5 IEEE 754 single precision data format 32 data bits 16 5 Key press COES orisiirisii ope e eTe in 16 10 Performance Verification Connections for volts verifi
212. h subsequent READ command will then trigger a single measurement and acquire the reading see READ for details If the instrument is in idle this command will execute immediately If the instrument is not in idle execution of the command will execute when the operation returns to the idle state When this command is executed Model 6514 will be configured as follows e The specified function is selected e All controls related to the selected function are defaulted to the RST values e The event control sources of the trigger model are set to immediate e The arm and trigger count values of the trigger model are set to one e The delay of the trigger model is set to zero e Model 6514 is placed in the idle state e All math calculations are disabled e Buffer operation is disabled A storage operation presently in process will be aborted e Autozero is enabled This command is automatically asserted when the MEASure command is sent Programming example The following command sequence selects and configures Model 65 14 for one shot measurements Each subsequent READ triggers a single measurement and requests the reading CONF VOLT Perform CONFigure operations READ Trigger measurement and request reading SCPI Signal Oriented Measurement Commands 15 3 B FETCh Request latest reading This command requests the latest post processed readings After sending this command and addressing Model 6514 to talk t
213. handlers Arm layer configuration menu When using a component handler the start of test option is selected from the Arm In menu item of the arm layer configuration menu To access the menu press SHIFT and then CONF ARM e ARM IN Select the start of test option IMM Immediate Test starts when LIMIT key is pressed TEST Test starts when the handler pulls the SOT line of the Digital I O high STEST Test starts when the handler pulls the SOT line of the Digital I O low NOTE The other arm in control sources are seldom used with component handlers but are available Perform limit tests Step 1 Configure test system As previously explained testing the system could be as simple as connecting a DUT to Model 6514 or could employ the use of a component handler for binning operations Step 2 Configure measurement Configure Model 6514 for the desired measurement as covered in the previous sections of this manual Step 3 Configure limit tests Configure Model 6514 for the limit tests as explained in Limit Test Configuration Step 4 Start testing process To enable the limit tests press the LIMIT key If the SOT line of the Digital I O port is being used by a component handler the test process will not start until the handler pulses the SOT line Otherwise the testing process will start when LIMIT is pressed Step 5 Stop testing process The testing process can be terminated at any time by again pre
214. hat yyyyy also provides build date and time information w is the board revision level Common Commands 14 3 B OPC operation complete Sets OPC bit OPC operation complete query Places a 1 in output queue When OPC is sent the OPC bit in the standard event register will set after all pending com mand operations are complete When OPC is sent an ASCII 1 is placed in the output queue after all pending command operations are complete Typically either one of these commands is sent after the INITiate command The INITiate command is used to take the instrument out of idle in order to perform measurements While operating within the trigger model layers all sent commands except DCL SDC IFC SYSTem PRESet RST GET and ABORt t will not execute After all programmed operations are completed the instrument returns to the idle state at which time all pending commands including OPC and or OPC are executed After the last pending command is executed the OPC bit and or an ASCII 1 is placed in the output queue Programming example The following command sequence will perform 10 measure ments After the measurements are completed in approximately 10 seconds an ASCII 1 will be placed in the output queue RST TRIG DEL 1 ARM COUN 10 Return 6514 to RST defaults idle Set trigger delay for 1 second Program for 5 measurements and stop 4 4 4 ww INIT Start measurements OPC S
215. he DUT is com pleted the appropriate digital output pattern is sent to the component handler which then places the DUT in the appropriate bin The component handler selects the next DUT and the testing process is repeated Handler 6514 Limit Tests 10 5 Figure 10 5 shows the basic limit testing flowchart expanded to include binning Notice that there are five possible output patterns one pass pattern and four fail patterns but only one will be sent to the component handler for each DUT that is tested Figure 10 5 Operation model for limit testing with binning Measure DUT HI Limit Failure O utput Fail Pattern Display ly LO Limit Failure O utput Fail Pattern O utput Fail Pattern HI Limit Failure Display LQ LO Limit Failure Display OK and Output Pass Pattern O utput Fail Pattern 10 6 Limit Tests Component handler interface Model 6514 is interfaced to a component handler via the Digital I O port as shown in Figure 10 6 The I O port has four lines for output signals and one line for input signals The input line is used to start the test and the output lines are used to send the test pass fail signal s to the com ponent handler to perform the binning operation Figure 10 6 6514 Handler Handler inter face connections Line 1 Line 2 Line 4 or EOT Relay Clamp Voltage V External Gnd Input SOT SOT Strobe Line
216. he SDC command performs essentially the same function as the DCL command except that only the addressed device responds Generally instruments return to their power up default conditions when responding to the SDC command GTL Go To Local The GTL command is used to remove instruments from the remote mode With some instruments GTL also unlocks front panel controls if they were previously locked out with the LLO command GET Group Execute Trigger The GET command is used to trigger devices to perform a specific action that depends on device configuration for example take a reading Although GET is an addressed command many devices respond to GET without addressing Address commands Addressed commands include two primary command groups and a secondary address group ATN is true when these commands are asserted The commands include LAG Listen Address Group These listen commands are derived from an instrument s pri mary address and are used to address devices to listen The actual command byte is obtained by ORing the primary address with 20 TAG Talk Address Group The talk commands are derived from the primary address by ORing the address with 40 Talk commands are used to address devices to talk SCG Secondary Command Group Commands in this group provide additional address ing capabilities Many devices including the Model 6514 do not use these commands U naddress commands The two unaddress comm
217. he correct Model 6514 measurement range e Set the calibrator current to the indicated value e Verify that Model 6514 current reading is within the limits given in the table EIO Or a Performance Verification 18 13 8 Repeat the procedure for negative source currents with the same magnitudes as those listed in Table 18 3 Table 18 3 20uA 20mA range current measurement accuracy reading limits Model 6514 amps reading limits Model 6514 range Calibrator current 1 Year 18 C 28 C 20uA 20 0000uA 19 9795 to 20 0205uA 200uA 200 000uA 199 795 to 200 205uA 2mA 2 00000mA 1 99790 to 2 00210mA 20mA 20 0000mA 19 9795 to 20 0205mA 20pA 2pA range accuracy Figure 18 3 Connections for 20pA 20uA range verification 1 Connect the voltage calibrator and Model 5156 Electrometer Calibration Standard to Model 6514 INPUT jack as shown in Figure 18 3 Initially make connections to the 100G resistor in the calibration standard DC Voltage Calibrator Model 6514 Electrometer BN C to dual Banana Plug Adapter OO0OO0O0000000 O00 oop O0O000 O00 O00 O00 OOO O00 OO ooo OCHI GG Connect Cable Shield to Output LO Low noise Triax Cable Coax Cable 1062 ice mome Note Connect Calibrator to Appropriate Resistor Link Shield and Chassis OU BPUT int A 100nF Model 5156 Calibration Standar
218. he readings are sent to the computer This command does not affect the instrument setup This command does not trigger a measurement The command simply requests the last group of readings Note that this command can repeatedly return the same readings Until there is a new reading s this command continues to return the old reading s If your application requires a fresh reading use the READ command This command is automatically asserted when the READ or MEASure command is sent C READ Trigger measurement s and request reading s This command is used to trigger and acquire readings The number of readings depends on how the trigger model is configured For example if configured for 20 measurements arm count 1 trigger count 20 20 sets of readings will be acquired When this command is sent the following commands execute in the order they are presented e INITiate e FETCh If the instrument is in the idle state INITiate takes the instrument out of idle to perform the programmed number measurements If the instrument is not in the idle state execution of this command will wait until it goes back into idle The FETCh command is executed to acquire the reading s The readings are sent to the computer when Model 6514 is addressed to talk NOTE Ifthe instrument is programmed to perform an infinite number of measurements arm count or trigger count set to infinite you cannot use the READ command to trigger and ac
219. hms Measurement Considerations located in this section 3 4 Volts and Ohms Measurements Volts and ohms measurement procedure CAUTION Themaximum input voltage to Mode 6514 is 250V peak E xceeding this value may cause damage to the instrument that is not covered by the warranty WARNING Themaximum common mode input voltage which is the voltage between theinput HI or LO and chassis ground is 500V peak Exceeding this value may create a shock hazard Step 1 Enable zero check and select the volts V or ohms Q function Zero check should always be enabled before making function or connection changes The ZCHK key toggles zero check on and off When on the ZC or ZZ message is displayed See Section 2 for details on zero check The volts function is selected by pressing the V key and the ohms function is selected by pressing the Q key NOTE Zero check will enable whenever the ohms function is selected Step 2 Enable or disable guard The GRD key toggles the driven guard on and off If performing unguarded measurements press GRD until the GUARD OFF message is displayed If performing guarded measure ments press GRD until the GUARD ON message is displayed WARNING Hazardous voltage may be present on the inner shield of the triax cable when GRD ison A metal safety shield connected to safety earth ground as shown in Figure 3 5 must be used for voltage measurements at or above 30V Step 3 P
220. ibeondses Volts calibration summary 20mA 20mA range amps calibration summary 19 11 20pA 2uA range amps calibration summary 19 13 Coulombs calibration summary 0 eee eect eeee eee teeeeee 19 15 Ohms calibration summary 00 0 eee eects eeeeeeteeeeeeenees 19 17 Routine Maintenance POWE IMO TUSE i aniano o E 20 3 Front panel tests scicscsestsciseccasdssssvevesdaceecstesctsus cbatectsestiaeeate tics 20 4 Status and Error Messages Status and error MESSAGES oe eee eee ee eeeeeeeceeseetaeeaeeeeenaee B 2 DDC Emulation Commands Device dependent command summary eeeeeeeeeseeeneees D 2 F Table F 1 Table F 2 Table F 3 Table F 4 Table F 5 Table F 6 G Table G 1 Table G 2 H Table H 1 IEEE 488 Bus O verview TEEE 488 bus command summary 0 ce eeeeceseereeseeeeeeeee F 7 Hexadecimal and decimal command codes 0 0 0 eee F 10 Typical bus sequence 0 eeeceeeeeeeseceececeeecaeceeeeceeeeeneeeneenes F 11 Typical addressed command sequence eeceeeeeeeseeeeeeeees F 11 IEEE command groups sceescessceeeceseeceseceececeeeeeneeeeeeenes F 12 Model 6514 interface function codes es eeeeeeeeteereeeeeeeee F 13 IEEE 488 and SCPI Conformance Information TEEE 488 documentation requirements 00 00 00 eee eee G 2 Coupled Commands cesciss cecscseveascsssccssansaeastaazsszseseassssabessapsens G 4 Calibration O ptions Calibration COMMANAS e ce ceeeeese
221. ice Pull Up Resistor B Z NAND b z ji Pin 1 F A E T V p rng y Setting digital output lines Digital output lines are set by selecting a decimal value 0 to 15 that corresponds to the 4 bit BCD pattern of the output To determine the value add up the decimal weight values for the desired HI lines Output HI Line Out 4 Out 3 Out 2 Out 1 Decimal Weight 8 4 2 1 For example to set output lines 3 and 1 HI 0101 bit pattern set the output value to 5 4 1 11 6 Digital 1 0 Analog O utputs and External Feedback Perform the following steps to set the digital output pattern from the front panel Press SHIFT and then CONF LIM to access the limits menu Press the A or y until LIMIT PASS is displayed Press ENTER The present digital output pattern value will be displayed ee OSS ENTER 5 Press EXIT to return to the normal display state SCPI programming digital output pattern Use the lt gt A and w keys to display the desired output pattern value 0 to 15 and press Table 11 1 SCPI commands digital outputs Command Description Default SOURce2 SOURce2 Subsystem TTL lt NRf gt or lt NDN gt Specify 4 bit digital output pattern see Parameter Values 15 TTL lt NRf gt lt NDN gt Query the digital output pattern The value returned is in the decimal format Parameter Values see Note Oto 15 Decimal format
222. igger TRIGger or not at all NONE NONE OUTPut Query output trigger status TRIGger SEQuence 1 Path to configure trigger layer vV SOURce lt name gt Select control source IMMediate or TLINk IMMediate Vv SOURce Query trigger control source Vv COUNt lt n gt Set measure count 1 to 2500 or INF infinite 1 Vv COUNt Query measure count vV DELay lt n gt Set trigger delay 0 to 999 9999 sec 0 0 vV AUTO lt b gt Enable or disable auto delay OFF vV AUTO Query state of auto delay vV DELay Query delay value vV 17 14 SCPI Reference Tables Table 17 9 cont TRIGger command summary Default Command Description parameter Ref SCPI TRIGger CLEar Clear input triggers immediately TCONfigure Vv DIRection lt name gt Enable SOURce or disable ACCeptor ACCeptor Vv bypass DIRection Query trigger source bypass vV ASYNchronous Configure input output triggers ILINe lt NRf gt Select input trigger line 1 2 3 4 5 or 6 1 ILINe Query input trigger line OLINe lt NRf gt Select output trigger line 1 2 3 4 5 or 6 2 OLINe Query output trigger line OUTPut lt name gt Output trigger after measurement SENSe or NONE OUTPut not at all NONE Query output trigger status Performance Venfication 18 2 Performance Verification Introduction Use the procedures in this section to verify that Model 6514 accuracy is within the limits stated
223. imum common mode input voltage which is the voltage between theinput HI or LO and chassis ground is 500V peak Exceeding this value may create a shock hazard NOTE After measuring high voltage in the volts function it may take several minutes for input current to drop to within specified limits Input current can be verified by plac ing the protection cap on the input triax connector and then installing the ground link between COMMON and CHASSIS ground With the instrument on the 20pA range and zero check disabled allow the reading to settle until the input bias current is within specifications The specifications for input bias current are listed in Appendix A Perform the following steps to measure charge Step 1 Enable zero check and select the coulombs Q function Zero check should always be enabled before making function or connection changes The ZCHK key toggles zero check on and off When on the ZC or ZZ message is displayed See Section 2 for details on zero check The coulombs function is selected by pressing the Q key Step 2 Select a manual measurement range or enable auto range Use the RANGE and keys to select a manual measurement range or press AUTO to enable auto range With auto range enabled the instrument will auto range between the HIGH range group 2uC and 20uC or the LOW range group 20nC and 200nC To select the HIGH range group press SHIFT and then the RANGE A key To select the LOW range
224. in remote You can restore normal front panel operation by pressing the LOCAL key Remote O peration 12 9 IFC interface clear The IFC command is sent by the controller to place all instruments on the bus in the local talker listener idle states Model 6514 responds to the IFC command by canceling front panel TALK or LSTN lights if the instrument was previously placed in one of those states Note that this command does not affect the status of the instrument settings data and event registers are not changed To send the IFC command the controller must set the IFC line true for a minimum of 100us LLO local lockout Use the LLO command to prevent local operation of the instrument After the unit receives LLO all its front panel controls except the POWER are inoperative In this state pressing the LOCAL will not restore control to the front panel The GTL command restores control to the front panel GTL go to local Use the GTL command to put a remote mode instrument into local mode The GTL command also restores front panel key operation DCL device clear Use the DCL command to clear the GPIB interface and return it to a known state Note that the DCL command is not an addressed command so all instruments equipped to implement DCL will do so simultaneously When Model 6514 receives a DCL command it clears the input buffer and output queue cancels deferred commands and clears any command that prevents the process
225. ine pin 6 the component handler can tell Model 6514 when it is ready for the test Via the digital out put lines Model 6514 sends digital output patterns to the component handler and tells it when the test is finished A digital output pattern determines which bin the DUT belongs in Digital I O Analog Outputs and External Feedback 11 3 NOTE Information on using the digital I O to control a component handler for limit tests is provided in Section 10 e External device control Each digital output can be used as a control switch for an external device i e relay circuit Each output line can sink up to 500mA Drive voltage is provided by an external source 5V to 33V e Logic Control The four digital outputs can be used as inputs to logic devices The simplified schematic for the digital outputs are shown in Figure 11 2 Note that this illus tration shows the schematic for one digital output All four digital output circuits are identical Figure 11 2 Digital I O port SS lt lt Pin 5 External Voltage Flyback sp connection 5V to 33V simplified schematic V Digital O uput _ Flyback Diode 1kQ Pull up e lt Digital O utput Ji Protection A Da Diode e lt Pin 9 Digital Ground V Sink mode controlling external devices Each output can be operated from an external supply voltage range from 5V to 33V applied through the external device being driven The high cur
226. ines ensure that proper data transfer and operation takes place Each bus line is active low with approximately zero volts representing a logic 1 true The fol lowing paragraphs describe the operation of these lines Data lines The IEEE 488 bus uses eight data lines that transfer data one byte at a time DIO1 Data Input Output through DIO8 Data Input Output are the eight data lines used to transmit both data and multiline commands and are bi directional The data lines operate with low true logic Bus management lines The five bus management lines help to ensure proper interface control and management These lines are used to send the uniline commands ATN Attention The ATN state determines how information on the data bus is to be interpreted IFC Interface Clear The IFC line controls clearing of instruments from the bus REN Remote Enable The REN line is used to place the instrument on the bus in the remote mode EOI End or Identify The EOI line is used to mark the end of a multi byte data transfer sequence SRQ Service Request The SRQ line is used by devices when they require service from the controller F 6 EEE 488 Bus Overview Handshake lines Figure F 2 IEEE 488 hand shake sequence The bus handshake lines operate in an interlocked sequence This method ensures reliable data transmission regardless of the transfer rate Generally data transfer will occur at a rate determined by
227. ing of any other device command A DCL does not affect instrument settings and stored data SDC selective device clear The SDC command is an addressed command that performs essentially the same function as the DCL command However since each device must be individually addressed the SDC com mand provides a method to clear only selected instruments instead of clearing all instruments simultaneously as is the case with DCL GET group execute trigger GET is a GPIB trigger that is used as an event to control operation Model 6514 reacts to this trigger if it is the programmed control source The control source is programmed from the SCPI TRIGger subsystem SPE SPD serial polling Use the serial polling sequence to obtain Model 65 14 serial poll byte The serial poll byte con tains important information about internal functions Generally the serial polling sequence is used by the controller to determine which of several instruments has requested service with the SRQ line However the serial polling sequence may be performed at any time to obtain the status byte from Model 6514 12 10 Remote O peration Front panel GPIB operation The following paragraphs describe aspects of the front panel that are part of GPIB operation including messages status indicators and the LOCAL key Error and status messages See Appendix B for a list of error and status messages associated with IEEE 488 program ming The instrument can be
228. ion eee cee eeseeseceseeeeceeeeeeceeeeeeseeeeeeeens 19 5 Current and charge calculations 0 0 0 eee eeeeceeeeeeeeeeeeeee 19 6 Manual calculations ee eceseeesseseeesecneecseseesaeesaeeaes 19 6 Automatic calculations e eee eecceeeeeeeeseeeseeeesneesseeaes 19 6 Calibration procedure oo ee eeceseeeeceseeeeeeeeeeeceeeeeeseneeeeeens 19 7 Preparing for calibration eee ce eee cee ceseeseceneeeeeeeees 19 7 Input bias current and offset voltage calibration 19 7 Volts calibration ennenen aona 19 8 Amps calibration ciicccsceicicsissceestevenssessacesansonaacsdscdarceoiussesne 19 10 Coulombs calibration eee ceceee cee ceeeeeeeeeeeeeeeeeeeeeees 19 14 Obms Calibration sists cscisciicn seve shes eeesee eee 19 16 Entering calibration dates and saving calibration 19 18 Locking out calibration eee ee eeeee cee ceeeceeeeseeeeeneees 19 18 Changing the calibration code 00 eee ee eeeeeeseeeeeeseeeseteeeeaee 19 18 Resetting the calibration code 0 eee eeeeeeeeeeeeseeereeseeeaes 19 19 Displaying calibration dates 0 0 eee eeeeeseeeeeeeeseeeeeseetaes 19 19 Displaying the calibration count 00 0 eee eeeeeeeeeseeeneeseeeaee 19 20 20 Routine Maintenance WiMEPODUC HON oreren e eea E RAEE 20 2 Setting line voltage and replacing line fuse ote eee 20 2 Front panel tests secina oeieo eenn enes 20 4 DISE TEST acsdacestosce teen dati oessccs chesytvesevessivsigsctoadneapeutensustocnsaces 20 4 KEY COS een
229. ion dependent The parameter can be defined as the capacitor s discharge current at a designated time following the initiation of a discharge cycle The capacitor is typically charged up to the maximum voltage that will be applied The measurement of the discharge current is usually made at a discharge time interval that will be used in the application of the device or no longer than one minute Acceptable capacitors have current levels below a required maximum limit Dielectric absorption can also be expressed as a percentage of residual voltage with respect to a charging voltage This ratio is determined by charging the capacitor to the rated voltage The capacitor is then discharged for a second time interval Finally the capacitor is open circuited and the residual voltage across the capacitor is measured after a third time constant The Model 6514 is particularly useful in measuring dielectric absorption because it draws vir tually no charge from the capacitor during the measurement nor does it induce charge on the capacitor being measured The test circuit in Figure 3 9A uses Keithley Model 230 as a voltage source and Model 6514 to perform the voltage measurements Figure 3 9B shows the voltage waveform across the capacitor during the three phases of the test Initially capacitor C is charged through R for the required soak time t in Figure 3 9B Soak time is typically one or two minutes depending on the capacitor value Next the vo
230. it B2 query error QY E Set bit indicates that you attempted to read data from an empty output queue Bit B3 device dependent error D D E Set bit indicates that an instrument operation did not execute properly due to some internal condition Bit B4 execution error EXE Set bit indicates that Model 6514 detected an error while trying to execute a command Bit B5 command error C ME Set bit indicates that a command error has occurred Command errors include JEEE 488 2 syntax error Model 6514 received a message that does not follow the defined syntax of the IEEE 488 2 standard gt Semantic error Model 6514 received a command that was misspelled or received an optional IEEE 488 2 command that is not implemented The instrument received a Group Execute Trigger GET inside a program message Bit B6 user request UR Q Set bit indicates that the LOCAL key on Model 6514 front panel was pressed Bit B7 power ON PON Set bit indicates that Model 6514 has been turned off and turned back on since the last time this register has been read 13 12 Status Structure Figure 13 4 Standard event status eon To ESB bit of Status Byte OR Register OPC ESE lt N Rf gt PON URQ CME EXE DDE QYE OPC ESE B15 B8 B7 B6 B5 B4 B3 B2 B1 Bo Decim
231. ity of the information transfer The basic handshake sequence between an active controller talker and a listener is as follows 1 The listener indicates that it is ready to listen The talker places the byte of data on the bus and indicates that the data is available to the listener 3 The listener aware that the data is available accepts the data and then indicates that the data has been accepted 4 The talker aware that the data has been accepted stops sending data and indicates that data is not being sent 5 The listener aware that there is no data on the bus indicates that it is ready for the next byte of data EEE 488 Bus Overview F 3 Bus description The IEEE 488 bus which is also referred to as the GPIB General Purpose Interface Bus was designed as a parallel transfer medium to optimize data transfer without using an excessive number of bus lines In keeping with this goal the bus has only eight data lines that are used for both data and with most commands Five bus management lines and three handshake lines round out the complement of bus signal lines A typical setup for controlled operation is shown in Figure F 1 Generally a system will con tain one controller and a number of other instruments to which the commands are given Device operation is categorized into three operators controller talker and listener The controller con trols the instruments on the bus The talker sends data while a listener receiv
232. kage current test 0 0 0 4 14 Connections cable insulation resistance test c eee 4 14 Connections surface insulation resistance test 00000000 4 15 5 Coulombs Measurements Figure 5 1 Typical connections for coulombs 0 0 cc eeeseeseeeeeeeeteeeeeeeee 5 4 Figure 5 2 Measuring capacitors oo eee ee ceeeeeceeeeeeceeeeeneeseeeseeseeeaeesaes 5 7 6 Range U nits Digits Rate and Filters Figure 6 1 Speed vs noise Characteristics cece csseeeseseeeeeseseeseeees 6 6 Figure 6 2 Digital filter types moving and repeating 00 eee eeeeee 6 9 8 Buffer Figure 8 1 Buffer locations sss esc sis sssisess caetacibia res iieii 8 3 9 Triggering Figure 9 1 Trigger model front panel operation 0 0 eee eee 9 2 Figure 9 2 Trigger model remote Operation 000 0 eee eee eeeeeeeeeeeees 9 3 Figure 9 3 Measure action block of trigger model 000 eee eects 9 6 Figure 9 4 Trigger link connection operation 0 ee eee ceeeeeeeeeeeeeeees 9 11 Figure 9 5 Trigger link input pulse specifications 0 0 0 eects 9 11 Figure 9 6 Trigger link output pulse specifications 0 eeeeeeeeeeeee 9 12 Figure 9 7 DUT test SYSTEM 36 ccs eeh rnasdisicsses setvons deos Ser ae 9 12 Figure 9 8 Trigger link connections ssssssesseesseererrerrsesrsrssrerrereersreee 9 13 Figure 9 9 Operation model for triggering example eceeeeeeeee 9 14 10 Limit Tests Figure 10 1 VMI TESTS rogei oree eienen E E E A Ean 10 2 Figure
233. key toggles between reading number and reading Sets user delay between trigger and measurement Enables disables damping for current measurements Stops measurement process Puts 6514 in idle state Trigger measurement s Takes 6514 out of idle state Cancels selection moves back to measurement display Accepts selection moves to next choice or back to measurement display Performs key press test or display test Accesses calibration Saves present setup to a memory location Restores setup stored in a memory location or to GPIB or factory defaults Configures Arm Layer of trigger model Configures Trigger Layer of trigger model Selects the next higher voltage measurement range Selects the next lower voltage measurement range Enables disables autorange Getting Started 1 7 4 Display annunciators asterisk Readings being stored in buffer lt gt more Indicates additional selections are available AUTO Autorange enabled BUFFER Recalling readings stored in buffer ERR Questionable reading or invalid cal step FAST Fast 0 1 PLC reading rate selected FILT Filter enabled LSTN Instrument addressed to listen over GPIB MATH mX b or Percent calculation enabled MED Medium 1 PLC reading rate selected REL Relative enabled for present measurement function REM Instrument in GPIB remote mode SHIFT Accessing a shifted key SLO W Slow reading rate selected 6 PLC for 60Hz or 5 PLC for 50Hz SRQ Service requ
234. kit Mounts Model 6514 and a 5 25 inch instru ment Models 195A 196 220 224 230 263 595 614 617 705 740 775A 6512 side by side in a standard 19 inch rack Carrying case Model 1050 padded carrying case A carrying case for Model 6514 Includes handles and shoulder strap System electrometer features Model 6514 is a 62 digit high performance system electrometer It can measure voltage cur rent resistance and charge Details on its measurement capabilities are explained in Section 2 of this manual see Measurement Overview Features of Model 6514 System Electrometer include Setup storage Five instrument setups three user GPIB defaults and factory defaults can be saved and recalled mX b and percent These calculations provide mathematical manipulation of readings Relative Null offsets or establish baseline values Buffer Store up to 2500 readings in the internal buffer Limits Set up to two stages of high and low reading limits to test devices Digital I O port Four output lines and one input line to control external circuitry Use as an interface between limit tests and component handler Analog outputs Provides a 2V analog output for a full range input Preamp out pro vides a driven guard for Volts or can be used for external feedback measurements External feedback Extends the measurement capabilities of the electrometer loga rithmic currents non decade current rang
235. l see Table 11 3 CAUTION Connecting preamp output common or 2V analog output to earth while floating the input may damage the instrument Table 11 3 Full range preamp out values Full range Function Range value Volts 2V 2V 20V 20V 200V 200V Amps 2nA 2uA 2mA 2V 20pA 20nA 20uA 20mA 20V 200pA 200nA 200HA 200V Ohms 2kQ 2MQ 2GQ 2V 20kQ 20MQ 20GQ 20V 200kQ 200MQ 200GQ 200V Coulombs 20nC 2uC 20V 200nC 20uC 200V Note that the preamp out output resistance is 192 The output resistance appears between input low and analog output low to keep the resistor out of the loop when using external feedback ele ments To keep loading errors under 0 1 the device connected to the preamp output should have a minimum input impedance of 100k CAUTION To prevent damage to Model 6514 do not connect a device to preamp out that will draw more than 100pA For example at 200V the impedance connected to preamp out must be at least 2MQ 200V 100pA 2M Q Digital 1 0 Analog Outputs and External Feedback 11 11 External feedback The external feedback function provides a means to extend the capabilities of Model 6514 electrometer to such uses as logarithmic currents non decade current ranges as well as non standard coulombs ranges The following paragraphs discuss the basic electrometer input cir cuitry and methods to implement these functions Electrometer input circuitry A simplified diagram of the elec
236. laneous SCPI commands 16 2 DISPlay FORMat and SYSTem D ISPlay subsystem Table 16 1 SCPI commands display Command D escription Default Ref DISPlay DIGits lt n gt Set display resolution 4 to 7 6 Sec 6 ENABle lt b gt Turn front panel display on or off see Note A WINDow 1 Path to control user text messages TEXT see Note DATA lt a gt Define ASCII message a up to 12 characters B STATe lt b gt Enable or disable text message mode C Note RST and SYSTem PRESet have no effect on the display circuitry and user defined text messages A DISPlay ENABle lt b gt With front panel circuitry turned off the instrument operates at a higher speed While dis abled the display is frozen and all front panel controls except LOCAL are disabled Normal display operations can be resumed by using ENABIle to enable the display pressing the LOCAL key or cycling power B DISPlay TEXT DATA lt a gt Message Types String aa a or aa a Indefinite Block 0aa a Definite Block XYaa a where Y number of characters in message up to 12 X number of digits that make up Y 1 or 2 The display message can be up to 12 characters ASCII long A space is counted as a char acter Excess message characters result in an error Note that for the string type the message must be enclosed by single or double quotes An indefinite block message must be the o
237. lean parameter lt b gt is used to enable or disable an instrument operation 1 or ON enables the operation and 0 or OFF disables the operation Upper case characters indicated the short form version for each command word Default parameter Listed parameters are both the RST and SYSTem PRESet defaults unless noted otherwise Parameter notes are located at the end of each table Ref Refers you to the section Sec that provides operation information for that com mand or command subsystem SCPI A checkmark V indicates that the command and its parameters are SCPI con firmed An unmarked command indicates that it is a SCPI command but does not con form to the SCPI standard set of commands It is not a recognized command by the SCPI consortium SCPI confirmed commands that use one or more non SCPI parameters are explained by notes Table 17 1 CALCulate command summary Default Command Description parameter Ref SCPI CALCulate 1 Path to configure and control CALC1 calculations Sec7 Vv FORMat lt name gt Select math format MXB or PERCent MXB Vv FORMat Query math format vV KMATh Configure math calculations MMFactor lt NRf gt Set m for mX b calculation 9 99999e20 to 1 0 9 99999e20 MMFactor Query m factor MBFactor lt NRf gt Set b for mX b calculation 9 99999e20 to 0 0 9 99999e20 MBFactor Query b factor MUNits lt name gt Specify units for mX b result 3
238. line 1 as the input and line 2 as the output DELAY Menu To access the menu for trigger delay press the DELAY key e DELAY Configure the trigger delay of the trigger layer MAN Manually set the delay 0 to 999 9998 seconds AUTO Selects auto delay The delay is set according to function range see Table 9 1 Triggering 9 9 SCPI programming Table 9 2 SCPI commands triggering Command Description Default Ref ABORt Reset trigger system goes to idle state A INITiate Initiate one trigger cycle B FETch Request latest reading B READ Trigger and request a fresh reading B ARM SEQuence 1 Arm Layer LAYer 1 SOURce lt name gt Select control source IMMediate TIMer BUS IMM C TLINk STESt PSTest NSTest BSTest or MANual COUNt lt n gt Set measure count 1 to 2500 or INF infinite 1 TIMer lt n gt Set timer interval 0 001 to 99999 999 sec 0 1 TCONfigure DIRection lt name gt Enable SOURce or disable ACCeptor bypass ACC D ASYNchronous Configure input output triggers ILINe lt NRf gt Select input trigger line 1 2 3 4 5 or 6 1 E OLINe lt NRf gt Select output trigger line 1 2 3 4 5 or 6 2 E OUTPut lt name gt Output trigger TRIGger or not at all NONE NONE TRIGger SEQuence 1 Trigger Layer SOURce lt name gt Select control source IMMediate or TLINk IMM COUNt lt n gt Set measure count 1 to 2500 or INF infinite 1 DELay lt n gt
239. ll SE Standard events 200 Operation complete SE Operation events 300 Device calibrating SE 303 Device sweeping SE 305 Waiting in trigger layer SE 306 Waiting in arm layer SE 310 Re entering the idle layer SE Questionable events 408 Questionable calibration SE 414 Command warning SE Calibration errors 500 Date of calibration not set EE 501 Next date of calibration not set EE 502 Calibration data invalid EE 507 Measurement offset data invalid EE 508 Measurement gain data invalid EE 509 Not permitted with cal locked EE 510 Not permitted with cal un locked EE 511 Voltage offset not converging EE 512 Current offset not converging EE Lost data errors 602 GPIB address lost EE 603 Power on state lost EE 604 DC calibration data lost EE 605 Calibration dates lost EE 606 GPIB communication language lost EE Communication errors 700 Invalid system communication EE 701 ASCII only with RS 232 EE Table B 1 cont Status and error messages Status and Error Messages Number Description Event Additional more informative command execution errors 800 Illegal with storage active EE 801 Insufficient vector data EE 804 Expression list full EE 805 Undefined expression exists EE 806 Expression not found EE 807 Definition not allowed EE 808 Expression cannot be deleted EE 811 Not an operator or number EE 812 Mismatched parentheses EE 813 Not a number of data handle EE 814 Mismatched brack
240. ll enable registers to 0 CLS has no effect 13 18 Status Structure Programming example program and read registers This command sequence programs and reads the measurement registers Registers are read using the binary format which directly indicates which bits are set The command to select for mat FORMat SREGister is documented in Table 13 2 FORM SREG BIN Select binary format to read registers STAT MEAS ENAB 512 Enable BFL buffer full STAT MEAS COND Read Measurement Condition Register STAT MEAS Read Measurement Event Register Queues Model 6514 uses two queues which are first in first out FIFO registers Output queue Used to hold reading and response messages Error queue Used to hold error and status messages Model 6514 status model Figure 13 1 shows how the two queues are structured with the other registers Output queue The output queue holds data that pertains to the normal operation of the instrument For example when a query command is sent the response message is placed in the output queue When data is placed in the output queue the message available MAV bit in the status byte register sets A data message is cleared from the output queue when it is read The output queue is considered cleared when it is empty An empty output queue clears the MAV bit in the status byte register A message is read from the output queue by addressin
241. llow Model 6514 to warm up for at least one hour before conducting the verification proce dures If the instrument has been subjected to temperature extremes those outside the ranges stated above allow additional time for the instrument s internal temperature to stabilize Typi cally allow one extra hour to stabilize a unit that is 10 C 18 F outside the specified temperature range Allow the test equipment to warm up for the minimum time specified by the manufacturer Line power Model 6514 requires a line voltage of 100 120 VAC or 220 240 VAC at a line frequency of 50 or 60Hz Verification tests must be performed within this range Performance Verification Recommended test equipment Table 18 1 summarizes recommended verification equipment You can use alternate equip ment but keep in mind that test equipment accuracy will add to the uncertainty of each measure ment Generally the test equipment should have accuracy or uncertainty at least four times better than corresponding Model 6514 specifications Table 18 1 Recommended verification equipment Description M anufacturer model Specifications Calibrator Resistance calibrator Electrometer calibration standard Fluke 5700A Fluke 5450A Keithley Model 5156 DC voltage 2V 7ppm 20V Sppm 200V 7ppm DC current 20uA 550ppm 200uA 100ppm 2mA 55ppm 20mA 55ppm Nominal resistance 1 9kQ 8ppm 19kQ 7 5ppm 190kQ 8 5ppm 1 9MQ
242. losed in single quotes However double quotes can instead be used Each measurement function remembers its own unique range setting B SEN Se D ATA This command does not trigger a reading It simply returns the last raw reading string It will not return the result of any instrument calculation The reading reflects what is applied to the input To return a fresh new reading you can send the INITiate command to trigger one or more readings before sending DATA Details on INITiate are provided in Section 9 While Model 6514 is busy performing measurements the DATA command will not return the reading string until the instrument finishes and goes into the idle state 5 6 Coulombs Measurements NOTES The format that the reading string is returned in is set by commands in the FORMat Subsystem see Section 16 If there is no reading available when DATA is sent an error 230 will occur The READ command can be used to return fresh readings This command triggers and returns the readings See Section 15 for details Programming example The following command sequence will perform one coulombs measurement Return 6514 to RST defaults Enable zero check Select the Coulombs function Enable auto range Connect input cable Disable zero check Enable Rel to zero the display Connect charge circuit to DUT Trigger and return one reading RST SYST ZCH ON FUNC CHAR CHAR RANG AU
243. ltage source is turned off and the capacitor is discharged through R t The capacitor is allowed to sit for a few minutes with S and S open t and the residual voltage is then measured by Model 6514 Dielectric absorption is then calculated as follows Dielectric Absorption Residual Voltage Soak Voltage x 100 Volts and O hms Measurements 3 15 Figure 3 9 Measuring dielectric R 1 absorption ga 230 VOLTAGE SOURCE Sz 2 H m 6514 _ va VOLTM ETER R2 Lo A Connections Discharge Soak lt gt Recovery lt _ gt T lt gt lt gt lt t A t Time gt B Voltage Waveform Amps M easurements Measurement overview Summarizes the current measurement capabilities of Model 6514 Amps measurement procedure Provides the procedure to measure amps High I mpedance measurement techniques Explains non driven guarding tech niques to eliminate leakage currents in high impedance test circuits SCPI programming Covers the basic SCPI commands used for the amps function Amps measurement considerations Covers measurement considerations that apply to amps measurements Applications Covers applications to measure diode leakage current capacitor leak age current cable insulation resistance and surface insulation resistance 4 2 Amps Measurements Measurement overview Amps measurements Model 6514 can make amps measu
244. lways tell Model 6514 what to send to the computer The following two steps must always be performed to send information from the instrument other computer 1 Send the appropriate query command s in a program message 2 Address Model 6514 to talk Rule 2 The complete response message must be received by the computer before another program message can be sent to Model 6514 Remote O peration 12 17 RS 232 interface reference Sending and receiving data The RS 232 interface transfers data using seven or eight data bits and one stop bit Parity selections include none odd or even RS 232 settings The procedure to select and configure the RS 232 interface is provided in Selecting and Configuring an Interface located at the beginning of this section Make sure the controller you connect to Model 6514 also uses these settings NOTE You can break data transmissions by sending a C or X character string to Model 6514 This clears any pending operation and discards any pending output Baud rate The baud rate is the rate at which Model 6514 and the programming terminal communicate You can choose from one of the following rates 57 6k 38 4k 19 2k 9600 4800 2400 1200 600 or 300 Make sure that the programming terminal that you are connecting to Model 6514 can support the baud rate you selected Both Model 6514 and the other device must be configured for the same baud rate Data and stop bits The RS 232 can be set to
245. m offset voltage calibration CAL UNPR VOFF 3 Allow the Model 6514 to complete the calibration process M easurement Concepts 2 19 Measurement considerations There are a variety of factors to consider when making low level measurements These con siderations are listed and summarized in Table 2 6 For comprehensive information on all mea surement considerations refer to the Low Level Measurements handbook which is available from Keithley Instruments Table 2 6 Summary of measurement considerations Considerations Description For V and Q measurements See Section 3 for details Loading effects Circuit loading caused by a high impedance voltage source Cable leakage resistance For unguarded measurements leakage resistance in the triax cable between HI and LO shunts the voltage to be measured Input capacitance settling At very high resistance levels effects of cable capacitance can slow time down measurement response time Guarding input cable Eliminates the effects of leakage resistance for high impedance measurements and input capacitance when using a long input cable For I measurements See Section 4 for details Input bias current Offset current of Model 6514 could affect low current measurements Voltage burden Offset voltage of Model 6514 could cause errors if it is high in relation to the voltage of the measured circuit Noise Noise generated by source resistance and source capacitance For Q measurements Se
246. mary bit of the status byte register Status Structure 13 3 Figure 13 1 Questionable Event Registers 6514 status Condition Event Event Enable Register Register Register mode structure 0 T e 0 T T 2 2 2 3 3 3 4 4 O 4 5 5 5 g 6 o 5 Calibration Summary Cal Cal Cal Logical 8 8 8 9 9 9 TO TO 10 2 HL i Error Queue 12 2 12 13 13 T3 5 Command Warning Warn Warn Warn gt Always Zero 15 15 15 CONDition EVENt ENABle lt NRf gt ENABle Output Queue Service Status Request Byte Enable Register Register MSB MSB Standard Event Registers T T Event Event Enable EAV EAV Register Register OSB OSB Logical Operation Complete MAV MAV OR ESB EB Query Error RQS MSS 6 Device Specific Error OSB OSB Execution Error STB SRE Command Error SRE User Request A Power On Logical M aster Summary Status M SS MSB M easurement Summary Bit EAV Error Available QSB Questionable Summary Bit MAV Message Available T2 ESB Event Summary Bit 13 B RQS MSS Request for Se
247. mbs function by pressing the Q key and set the calibrator to the DC volts function With zero check enabled zero correct the instrument then disable zero check Set the calibrator voltage to 0 0000V and turn on its output Enable the REL mode and leave REL enabled for the remainder of the test Performance Verification 18 19 7 Verify charge measurement accuracy for each of the values listed in Table 18 7 For each test point e Select the correct Model 6514 measurement range e Make connections to the correct standard capacitor e Calculate the required voltage from the desired charge and actual standard capaci tance value V Q C e Disable zero check e Set the calibrator voltage to the calculated value e Verify that Model 6514 charge reading is within the required limits e Enable zero check to discharge the capacitor Table 18 7 Coulombs measurement accuracy reading limits Nominal Model calibrator Standard Actual Mode 6514 coulombs reading 6514 range voltage capacitor Applied charge voltage2 limits 1 Year 18 C 28 C 20nC 20V InF 20 0000nC V 19 9915 to 20 0805nC 200nC 200V InF 200 000nC V 199 195 to 200 805nC 2uC 20V 100nF 2 00000uC V 1 97995 to 202 02005uC 20uC 200V 100nF 20 0000uC V 19 7995 to 20 2005uC Nominal values 2 Calculate actual voltage from applied charge and actual capacitance value V Q C _ 19 Calibration 19 2 Calibration Introduction Use the proced
248. measurement process Measurement considerations Summarizes the various factors that affect low level measurements 2 2 Measurement Concepts Measurement overview The basic measurement capabilities of Model 6514 are summarized in Table 2 1 Accuracy for each measurement function and range is listed in specifications Appendix A Table 2 1 Basic measurement capabilities Function Reading Range Available R anges Volts 10uV to 210V 2V 20V and 200V Amps 100aA to 21mA 20pA 200pA 2nA 20nA 200nA 2uA 20uA 200uA 2mA and 20mA Ohms 10mQ to 210GQ 2kQ 20kQ 200kQ 2MQ 20M9 200M2 2GQ 20GQ and 200GQ Coulombs 10fC to 21pC 20nC 200nC 2uC and 20uC Performance considerations Warm up period Model 6514 can be used within one minute after it is turned on However the instrument should be turned on and allowed to warm up for at least one hour before use to achieve rated accuracy If the instrument has been exposed to extreme temperatures allow extra time for the internal temperature to stabilize Autozero To help maintain stability and accuracy over time and changes in temperature the Model 6514 periodically measures internal voltages corresponding to offsets zero and amplifier gains These measurements are used in the algorithm to calculate the reading of the input signal This process is known as autozeroing When autozero is disabled the offset and gain measurements are not performed This
249. measuring instruments should be placed on their lowest ranges The configuration that results in the lowest noise signal is the one that should be used Figure C 2 Instrument 1 Instrument 2 Instrument 3 Eliminating ground loops Power Line Ground Triboelectric effects Triboelectric currents are generated by charges created between a conductor and an insulator due to friction Here free electrons rub off the conductor and create a charge imbalance that causes the current flow For example bending a triaxial cable causes friction between the center conductor HI and its surrounding insulator resulting in triboelectric currents Triboelectric cur rents can be minimized as follows e Use low noise cables These cables are specially designed to minimize charge gener ation and use graphite to reduce friction The Keithley Model 7078 TRX triax cables are low noise e Use the shortest cables possible and secure them i e taping or tying to a non vibrating surface to keep them from moving Piezoelectric and stored charge effects Piezoelectric currents are generated when mechanical stress is applied to certain insulating materials i e crystalline In some plastics pockets of stored charge cause the material to behave in a similar manner When building test fixtures choose good insulating materials and make connecting structures as rigid as possible Make sure there are no mechanical stresses on the insulators C 4 Gene
250. mple for a binary value of 100101 bits B5 B3 and BO are set The returned value can be in the binary decimal hexadecimal or octal format The FORMat SREGister command is used to select the data format for the returned value see Table 13 2 For non decimal formats one of the following headers will accompany the returned value to indicate which format is selected B Header for binary values H Header for hexadecimal values Q Header for octal values Table 13 2 SCPI command data formats for reading status registers Command Description Default FORMat FORMat subsystem SREGister lt name gt Select data format for reading status registers ASCii lt name gt ASCii Decimal format HEXadecimal Hexadecimal format OCTal Octal format BINary Binary format Status Structure 13 7 Status byte and service request SRQ Service request is controlled by two 8 bit registers the status byte register and the service request enable register Figure 13 3 shows the structure of these registers Figure 13 3 Status Summary Messages 6 Status byte and service request i Service RQS Request STB ESB MAV QSB EAV M SB Status Byte Generation Serial Poll Register Ma OR SRE OSB ESB MAV QSB EAV MSB Service Request SRE B7 B6 B5 B4 B3 B2 B
251. mple the talk address derived from a primary address of 14 would be 54 54 14 40 The IEEE 488 standards also include another addressing mode called secondary addressing Secondary addresses lie in the range of 60 7F Note however that many devices including the Model 6514 do not use secondary addressing Once a device is addressed to talk or listen the appropriate bus transactions take place For example if the instrument is addressed to talk it places its data string on the bus one byte at a time The controller reads the information and the appropriate software can be used to direct the information to the desired location F 4 EEE 488 Bus Overview Figure F 1 IEEE 488 bus configuration TO OTHER DEVICES _ A ABLE TO TALK LISTEN EH AND CONTROL as COMPUTER iii DATA BUS dq D DEVICE 2 No ABLETO EH TALKAND EH LISTEN y DATA BYTE 6514 m m m m m m ae TRANSFER TP CONTROL DEVICE 3 ONLY ABLE ni TO LISTEN m nA TARA PRINTER Eeey INTERFACE riii ii MANAGEMENT DEVICE4 E ONLY ABLE DIO 1 8 DATA TO TALK H 8 LIN ES HHH H DAV NRFD HANDSHAKE NDAC IFC ATN BUS SRQ MANAGEMENT REN EOI EEE 488 Bus Overview F 5 Bus lines The signal lines on the IEEE 488 bus are grouped into three different categories data lines management lines and handshake lines The data lines handle bus data and commands while the management and handshake l
252. n C Document Number 6514 901 01 December 1998 December 1998 Revision D Document Number 6514 901 01 eeeecessseeseeeseeseeeeneeseeeeeeceeaeeeeereaeeaeeeee All Keithley product names are trademarks or registered trademarks of Keithley Instruments Inc Other brand names are trademarks or registered trademarks of their respective holders Safety Precautions The following safety precautions should be observed before using this product and any associated instrumentation Although some instruments and accessories would normally be used with non hazardous voltages there are situations where hazardous conditions may be present This product is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety precautions required to avoid possible injury Read and follow all installation operation and maintenance information carefully before us ing the product Refer to the manual for complete product specifications If the product is used in a manner not specified the protection provided by the product may be impaired The types of product users are Responsible body is the individual or group responsible for the use and maintenance of equipment for ensuring that the equip ment is operated within its specifications and operating limits and for ensuring that operators are adequately trained Operators use the product for its intended function They must be trained in electrical safety proce
253. n for the 2V Analog Output and Preamp O ut 5 CHASSIS This terminal is connected to the chassis of M odel 6514 and to power line earth ground via the power line cord For floating measurements up to 500V peak remove the ground link between COMMON and CHASSIS Getting Started 1 9 6 IEEE 488 Connector for IEEE 488 GPIB operation Use a shielded cable such as Models 7007 1 and 7007 2 7 DIGITALI O Male DB 9 connector for digital output lines and component handler signals 8 TRIGGER LINK Eight pin micro DIN connector for sending and receiving trigger pulses among connected instru ments Use a trigger link cable or adapter such as Models 8501 1 8501 2 8502 and 8503 9 RS 232 Female DB 9 connector for RS 232 operation Use a straight through not null modem DB 9 shielded cable 10 Power module Contains the AC line receptacle power line fuse and line voltage setting The instrument can be con figured for line voltages of 100V 120V 220V 240VAC at line frequencies of 50 or 60Hz 1 10 Getting Started Power up Line power connection Perform the following procedure to connect Model 6514 to line power and turn on the instrument 1 Check to be sure the line voltage setting on the power module is correct for the operating voltage in your area The line voltage setting is indicated in the window on the power module see Figure 1 2 The upside down 120 setting is for line voltages of 100 120VAC and the upside do
254. n the 20pA range and zero check disabled allow the reading to settle until the input bias current is within specifications The specifications for input bias current are listed in Appendix A Perform the following steps to measure current Step 1 Enable zero check and select the amps I function Zero check should always be enabled before making function or connection changes The ZCHK key toggles zero check on and off When on the ZC or ZZ message is displayed See Section 2 for details on zero check The amps function is selected by pressing the I key Amps M easurements 4 3 Step 2 Perform zero correction To achieve optimum accuracy for low current measurements it is recommended that you zero correct the electrometer To do so select the 20pA range which is the lowest range and press the ZCOR key until the ZZ message is displayed See Section 2 for details on zero correction Step 3 Select a manual measurement range or enable auto range Use the RANGE 4 and y keys to select a manual measurement range or press AUTO to enable auto range With auto range enabled the instrument will automatically go to the most sensitive range to make the measurement See Section 6 for details on range Step 4 Connect the current to be measured to the electrometer Basic connections for amps measurements are shown in Figure 4 1 NOTE Fundamental information on making connections to the electrometer input is pro vided in S
255. nab lt NRf gt When the above is sent the first command word is recognized as the root command stat When the next colon is detected the path pointer moves down to the next command level and executes the command When the path pointer sees the colon after the semicolon it resets back to the root level and starts over Commands that are on the same command level can be executed without having to retype the entire command path Example stat oper enab lt NRf gt enab After the first command enab is executed the path pointer is at the third command level in the structure Since enab is also on the third level it can be entered without repeating the entire path name Notice that the leading colon for enab is not included in the program message If a colon were included the path pointer would reset to the root level and expect a root command Since enab is not a root command an error would occur Remote O peration 12 15 Command path rules e Each new program message must begin with the root command unless it is optional e g SENSe If the root is optional simply treat a command word on the next level as the root e The colon at the beginning of a program message is optional and need not be used Stat pres stat pres e When the path pointer detects a colon it moves down to the next command level An exception is when the path pointer detects a semicolon which is used to separate com mand
256. nassbeneseaddeoes 5 2 Coulombs measurement procedure eee eee eeeeseceeeeteeeeees 5 3 SCPI programming occ eee ceseeseceeceseceeceseeeeeeseeeeseseeeeeeaeeees 5 5 Programming example oo eee eee cee ceeeseceseeseceeeeeneneeeees 5 6 Coulombs measurement considerations 00 0 0 cece eeeeeeeeees 5 6 Input bias CULLEN eesersesseoneesereecesesenessersoesseesssonees 5 6 External voltage source oo eee eeeeeeeeeseeeseeseecseceeeneenaes 5 6 Zero check hop and auto discharge hop ce eee 5 7 Application ssssii sees sesitecuanstadsspesesseashecanous tee a E EE E EER 5 7 Capacitance measurements eseseseseeeeseeeseeresrerssrrersrrersreee 5 7 Range U nits Digits Rate and Filters Range units and digits 0 cee eeseesseeeeecseceececeeeeeeeceeeecnseeeneeeee 6 2 RANSE doneta o e E E sutnpsusgecniareets 6 2 VOE E A E E eoteaturemensesaocs 6 4 DISS ebanean R A R E 6 4 SCPI programming range and digits eee 6 4 RAIE ees sees sdascesp cesta ses cc teegsnsiseucucuinsveseoindaeors cGesganesdeused sutvacuseusnensones 6 6 SCPI programming rate oo eee eeeeecseeseeneeeseenees 6 7 FIETS pcx vesies sx cucsvses peteaeenss Sones E I E R 6 8 Median filter 2 5 csscis gscszereissesheanesetsteusinetoevocpsensasotencusensesacnnes 6 8 Digital MME vereion oeenn 6 9 SCPI programming filters oo eee eeeeeseeeeceteeeeees 6 10 Relative mX b and Percent REVAUVC Srcesdes gocvsei Nesp nen e EE E 7 2 Setting and
257. nd terminator are sent only once for each READ During binary transfers never un talk Model 6514 until after the data is read input to the computer Also to avoid erratic operation the readings of the data string and terminator should be acquired in one piece The header 0 can be read separately before the rest of the string The number of bytes to be transferred can be calculated as follows Bytes 2 Rdgs x 4 1 where 2 is the number of bytes for the header 0 Rdgs is the product of the number of selected data elements arm count and trigger count 4 is the number of bytes for each reading 1 is the byte for the terminator 16 6 DISPlay FO RMat and SYSTem For example assume the instrument is configured to perform 10 measurements and send them to the computer using the binary format 2 10x4 1 43 Bytes B FORMatELEMents lt item list gt Parameters READing Voltage current resistance or charge reading TIME Timestamp STATus Status information The specified elements are included in the data string in response to FETch READ MEASure and TRACe DATA Note that each element in the item list must be separated by a comma i e send ELEMents READing TIME STATus to include all elements in the data string The elements for the ASCii format are shown in Figure 16 1 An overflow reading is returned as 9 9E37 When a specified data element has invalid data associated with it NAN Not A
258. nd will not go into the queue As listed in Table 13 7 there are commands to enable and or disable messages For these commands the lt list gt parameter is used to specify which messages to enable or disable The messages are specified by their codes The following examples show various forms for using the lt list gt parameter lt list gt 110 Single message 110 222 Range of messages 110 through 222 110 222 220 Range entry and single entry separated by a comma When you enable messages messages not specified in the list are disabled When you disable messages each listed message is removed from the enabled list NOTE To prevent all messages from entering the error queue send the enable command along with the null list parameter as follows STATus QUEue ENABle 13 20 Status Structure Table 13 7 SCPI commands error queue Command Description Default STATus STATus subsystem QUEue Read error queue Note 1 NEXT Read and clear oldest error status code and message ENABle lt list gt Specify error and status messages for error queue Note 2 ENABle Read the enabled messages DISable lt list gt Specify messages not to be placed in queue Note 2 DISable Read the disabled messages CLEar Clear messages from error queue SYSTem SYSTem subsystem ERRor Read error queue Note 1 NEXT Read and clear oldest error status code and message ALL Read and clea
259. nential notation For example a displayed reading of 2 500E 03 is equivalent to 2500 2 5K Rel can be used on the result of the mX b or percent math operation Note however that Rel will disable whenever a math function is enabled or disabled See Relative for details on using Rel 7 6 Relative mX b and Percent SCPI programming mX b and percent Table 7 3 SCPI commands mX b and percent Commands Description Default Ref CALCulate 1 CALCulate1 Subsystem FORMat lt name gt Select calculation MXB or PERCent MXB KMATh Path to configure mX b and percent MMFactor lt n gt Specify scale factor M for mX b 9 99999e20 to 1 0 9 99999e20 MBFactor lt n gt Specify offset B for mX b 9 99999e20 to 9 99999e20 0 0 MUNits lt name gt Specify units for mX b 3 characters A through Z MXB PERCent Percent 1 0 REFerence lt n gt Specify reference value 9 99999e20 to 9 99999e20 ACQuire Use input signal as reference value STATe lt b gt Enable or disable the selected calculation OFF DATA Returns all CALC1 results triggered by the INITiate A DATA LATest Returns only the latest CALC1 reading A A DATA and DATA LATest The INITiate command must be sent to trigger the measurements and calculations The number of calculations depend on how many measurements the instrument is programmed to perform If the instrument is programmed to perform a finite number
260. nformation on precision measurements refer to the Low Level Measurements handbook which is available from Keithley Instruments Loading effects Circuit loading can be detrimental to high impedance voltage measurements To see how meter loading can affect accuracy refer to Figure 3 4 Rg represents the resistance component of the source while Ryy represents the input resistance of the meter The percent error due to loading can be calculated using the formula in the illustration To keep the error under 0 1 the input resistance Rn must be about 1000 times the value of the source resistance Rs The input resistance of Model 6514 is gt 200T Therefore to keep the error under 0 1 the source resis tance of the measured voltage must be lt 200GQ Figure 3 4 Source Meter Meter loading u Q 100Rs Ret Rin Error Cable leakage resistance In an unguarded voltage measurement leakage current occurs in the input triax cable between the center conductor HI and the inner shield LO This leakage resistance shunts the voltage source to be measured If the resistance of the source is not significantly less than the leakage resistance of the cable measurement errors will occur The effects of leakage resistance can be eliminated by using guard to make high impedance voltage measurements See Guarding Input Cable for more information In general guarding should be used when DUT resistanc
261. ng 10 2 Limit Tests 10 1 Line frequency selection 1 10 Line power 18 3 19 2 Line power connection 1 10 Loading effects 3 9 Locking out calibration 19 18 Logarithmic currents 11 15 Low noise input cables 2 5 Magnetic fields C 5 Manual calculations 19 6 Measurement Concepts 2 1 Measurement considerations 2 19 C 2 Measurement overview 2 2 3 2 4 2 5 2 Median filter 6 8 mX b 7 4 mX b and percent 7 4 Noise 4 10 Non decade current gains 11 16 Non standard coulombs ranges 11 13 Offset voltage calibration 18 9 Ohms calibration 19 16 Ohms measurement accuracy 18 15 One shot triggering E 3 Options and accessories 1 3 Output queue 13 18 Output trigger specifications 9 12 Overview 13 2 Percent 7 5 Perform limit tests 10 11 Performance considerations 2 2 Performance Verification 18 1 Performing the verification test procedures 18 8 Piezoelectric and stored charge effects C 3 Power up 1 10 Power up sequence 1 11 Preparing for calibration 19 7 Primary address selection 12 7 Programming and reading registers 13 5 Programming enable registers 13 5 Programming example 3 8 4 9 5 6 8 6 9 10 10 15 Programming examples E 2 Programming syntax 12 11 Queues 13 18 Range 6 2 Range units and digits 6 2 Range Units Digits Rate and Filters 6 1 Rate 6 6 Reading calibration standard values H 2 Reading registers 13 6 Reading values H 2 Rear panel summary 1 8 Recalculating resistance reading limits 18 6
262. ng between the controller and Model 6514 Data will be lost if transmitted before the receiving device is ready RS 232 connections The RS 232 serial port can be connected to the serial port of a controller i e personal com puter using a straight through RS 232 cable terminated with DB 9 connectors Do not use a null modem cable The serial port uses the transmit TXD receive RXD and signal ground GND lines of the RS 232 standard It does not use the hardware handshaking lines CTS and RTS Figure 12 4 shows the rear panel connector for the RS 232 interface and Table 12 2 shows the pinout for the connector 54321 RS 232 interface connector Gee 987 6 RS232 Rear Panel Connector If your computer uses a DB 25 connector for the RS 232 interface you will need a cable or adapter with a DB 25 connector on one end and a DB 9 connector on the other wired straight through not null modem Table 12 3 provides pinout identification for the 9 pin DB 9 or 25 pin DB 25 serial port connector on the computer PC Table 12 2 RS 232 connector pinout Pin number Description 1 DCD data carrier detect 2 TXD transmit data 3 RXD receive data 4 DTR data terminal ready 5 GND signal ground 6 DSR data set ready 7 RTS ready to send 8 CTS clear to send 9 No connections RTS and CTS are tied together DCD DTR and DSR are tied together Remote O peration Table 12 3 PC serial port pinout DB 9 DB 25
263. nly command in the program message or the last command in the program message If you include a command after an indefinite block message on the same line it will be treated as part of the message and is displayed instead of executed DISPlay FORM at and SYSTem 16 3 C DISPlay TEXT STATe lt b gt When the text message mode is enabled a defined message is displayed When disabled the message is removed from the display GPIB operation A user defined message remains displayed only as long as the instrument is in remote Taking the instrument out of remote by pressing LOCAL or sending the GTL go to local command or cycling power cancels the message and disables the text message mode RS 232 operation A user defined message can be cancelled by sending SYSTem LOCal pressing LOCAL or cycling power 16 4 DISPlay FORMat and SYSTem FO RMat subsystem The commands in this subsystem are used to select the format for transferring data over the bus Table 16 2 SCPI commands data format Command Description Default Ref FORMat DATA lt type gt lt length gt Specify data format ASCii REAL 32 or SREal ASCii A ELEMents lt item list gt Specify data elements READing TIME and All 3 B STATus BORDer lt name gt Specify byte order NORMal or SWAPped see Note C SREGister lt name gt Select data format for reading status registers ASC Sec 13 ASCii HEXadecimal OCTal or BINary
264. nterface card Edit the following line to where the QuickBASIC libraries are on your computer SINCLUDE c qb45 ieeeqb bi Initialize the CEC interface as address 21 CALL initialize 21 0 Reset controls and put trigger model in IDLE state CALL SEND 14 rst status Reset STATus subsystem not affected by RST CALL SEND 14 stat pres cls status CALL SEND 14 stat meas enab 512 status enable BFL CALL SEND 14 sre 1 status enable MSB CALL SEND 14 trig coun 20 status TRACe subsystem is not affected by RST CALL SEND 14 trac poin 20 status CALL SEND 14 trac feed sensl feed cont next status Start everything CALL SEND 14 init status Initialize reading while the 6514 is busy taking readings readingS SPACES 4000 WaitSRQ IF NOT srq THEN GOTO WaitSRQ CALL SPOLL 14 poll status E 6 Example Programs IF poll AND 64 0 THEN GOTO WaitSRQ CALL SEND 14 stat meas status CALL ENTER SS length 14 status CALL SEND 14 trac data status CALL ENTER reading length 14 status PRINT reading NOTE To repeat buffer storage send the following command and then repeat the steps fol lowing the Start everything comment in the above example CALL SEND 14 feed cont next status Taking readings using the READ
265. odel 6514 20V range accuracy specification of 0 025 of reading 3 counts the calculated reading limits are Reading limits 20V 20V x 0 025 300uV 20V 0 005 0 0003 20V 0 0053V 19 9947V to 20 0053V Recalculating resistance reading limits When verifying resistance measurement accuracy it will probably be necessary to recalculate resistance limits based on the actual resistance values You can calculate new reading limits in the same manner described above but be sure to use the actual calibration resistance values and Model 6514 ohms accuracy specifications for your calculations As an example assume that you are testing the 20kQ range and that the actual value of the nominal 19k calibrator resistor is 19 1kQ Using Model 6514 20k range accuracy specifica tions of 0 15 of reading 3 counts the recalculated reading limits are Reading limits 19 1kQ 19 1k x 0 15 0 3Q 19 1kQ 29Q 19 0710kQ to 19 1290kQ Performance Verification 18 7 Calibrator voltage calculations When verifying the 20pA 2uA current ranges and all charge ranges you must calculate the actual calibrator voltages from the desired current or charge values and the characterized Model 5156 Calibration Standard resistor and capacitor values Current calculations Calibrator voltages required for verification currents are calculated as follows V IR Where V required calibrator voltage I verification current R act
266. oduction ccccccccccsccccccesssssccececssececceceeseseceecsensseseeeeenenseeeees F 2 Bus description sisson eie onie veevesensduates F 3 Bus lines oo eeeccccccecccesssssecececesseaeecececesaececcecseseseceeceessaeseeeeeneneeeees F 5 Data SS F 5 Bus management lines oo eee cee ceseeeeceseeeeeeeeeeeeeeeee F 5 Handshake lines cccccsescccceesssscececesessseceeecessaeeeeeeesaees F 6 Bus commands 0 0 0 0 cecesesssceeceesssececeeesenececccesessseeececessaeeeeceeeaees F 7 Uniline commands 00 0 0 cccccecceccccsescececesesseeceeecessaeeeeceeesaees F 8 Universal multiline commands cccccscccecesesssceeeeeeneee F 8 Addressed multiline commands ccccecccccessssceeeeeesteee F 9 Address commands 0 cccceseccessssscececesenssecececesseaeececeeseaes F 9 Unaddress commands cccccsesscccecesesseecececessaeeeeceeseaees F 9 Common commands c ccccccessesecececesenseecececsssseeeeeeeeees F 10 SCPI commands 20 0 cccccccceceessseceeceesseceeeeessnsseeecesssssaeees F 10 Command codes ccccccecsssececeeessesececeseseececeesssseeeeeeeaees F 10 Typical command sequences esceceeeeeseceeeeeeteeessecenees F 11 TEEE command groups ssesseeeesseersseereesesreesrerrsreeerrrereres F 12 Interface function codes seonseennseeneosenerenesseneernssrernesnsrreresse F 13 IEEE 488 and SCPI Conformance Information TNtHOCUCH ON seriene erar ea EEE EEN EE aE G 2 Calibration O ptions Trit
267. of measurements the DATA command will return all the CALC1 readings after the last reading is taken The DATA LATest command will only return the last latest CALC1 reading If the instrument is programmed to perform an infinite number of measurements arm count or trigger count set to infinite you cannot use the DATA command to return CALC readings However you can use the DATA LATest command to return the last CALC1 reading after aborting the measurement process After sending the INITiate command to start the measure ment process use the ABORt command to abort the measurement process then use DATA LATest to return the last CALC1 reading Programming example mX b This command sequence performs a single mX b calculation and displays the result on the computer CRT RST Restores RST defaults CALC FORM MXB Selects mX b calculation CALC KMAT MMF 2 Sets scale factor M to 2 CALC KMAT MBF 0 5 Sets offset B to 0 5 CALC STAT O Enables calculation INIT Perform one measurement and calculate mX b CALC DATA Request mX b result Buffer Buffer operations Explains how to store and recall readings including buffer Statistics SCPI programming Covers the SCPI commands used to control buffer operations 8 2 Buffer Buffer operations Model 6514 has a buffer to store from one to 2500 readings It also stores overflow readings Each reading h
268. of the instrument to request ser vice from the controller RL Remote Local F unction RL1 defines the ability of the instrument to be placed in the remote or local modes F 14 EEE 488 Bus Overview PP Parallel Poll Function The instrument does not have parallel polling capabilities PPO DC Device C lear Function DC1 defines the ability of the instrument to be cleared ini tialized DT DeviceTrigger Function DTI defines the ability of the Model 6514 to have readings triggered C Controller Function The instrument does not have controller capabilities CO TE Extended Talker Function The instrument does not have extended talker capabili ties TEO LE Extended Listener Function The instrument does not have extended listener capa bilities LEO E Bus Driver Type The instrument has open collector bus drivers E1 G EEE 488 and SCPI Conformance Information G 2 IEEE 488 and SCPI Conformance Information Introduction The IEEE 488 2 standard requires specific information about how the Model 6514 imple ments the standard Paragraph 4 9 of the IEEE 488 2 standard Std 488 2 1987 lists the docu mentation requirements Table G 1 provides a summary of the requirements and provides the information or references the manual for that information Table G 2 lists the coupled com mands used by the Model 6514 The Model 6514 complies with SCPI version 1991 0 Tables 17 1 th
269. of the status byte register The commands to program and read the event enable registers are listed in Table 13 6 For details on programming and reading registers see Programming enable registers and Read ing registers NOTE The bits of any enable register can be reset to 0 by sending the 0 parameter value with the appropriate enable command i e STATus OPERation ENABle 0 Table 13 6 Common and SCPI commands event enable registers Command Description ESE lt NDN gt or lt NRf gt ESE STATus OPERation ENABle lt NDN gt or lt NRf gt ENABle MEASurement ENABle lt NDN gt or lt NRf gt ENABle QUEStionable ENABle lt NDN gt or lt NRf gt ENABle Program standard event enable register see Parameters Read standard event enable register STATus subsystem Operation event enable register Program enable register see Parameters Read enable register Measurement event enable register Program enable register see Parameters Read enable register Questionable event enable register Program enable register see Parameters Read measurement event enable register Parameters lt NDN gt Bxx x Hx Qx lt NRf gt 0 to 65535 Binary format each x 1 or 0 Hexadecimal format x 0 to FFFF Octal format x 0 to 177777 Decimal format Note Power up and STATus PRESet resets all bits of a
270. on that pertains exclusively to remote operation is provided after each table The SCPI tables may reference you to other sec tions of this manual NOTE Except for Section 17 most SCPI tables in this manual are abridged That is they exclude most optional command words and query commands Optional command words and query commands are summarized as follows Optional command words In order to be in conformance with the IEEE 488 2 standard Model 6514 accepts optional command words Any command word that is enclosed in brackets is optional and does not have to be included in the program message Query commands Most command words have a query form A query command is iden tified by the question mark that follows the command word A query command requests que ries the programmed status of that command When a query command is sent and Model 6514 is addressed to talk the response message is sent to the computer NOTE For complete details see Programming Syntax in Section 12 Measurement Concepts Measurement overview Explains the basic measurement capabilities of Model 6514 Performance considerations Covers a couple of considerations that affect overall performance warm up and autozero Connection fundamentals Covers fundamental information about connecting test circuits to the electrometer Zero check and zero correct Provides operation information on these two important aspects of the basic
271. ont STATus command summary SCPI Reference Tables Default Command Description parameter Ref SCPI ENABle lt NDN gt or Program the enable register Note 3 V lt NRf gt ENABle Read the enable register V CONDition Read the condition register vV QUEStionable Questionable event registers v EVENt Read the event register Note 2 Vv ENABle lt NDN gt or Program the enable register Note 3 vV lt NRf gt ENABle Read the enable register vV CONDition Read the condition register vV PRESet Return status registers to default states vV QUEue Read error queue vV NEXT Read and clear oldest error status code and Note 4 v message ENABle lt list gt Specify error and status messages for error Note 5 vV queue ENABle Read the enabled messages vV DISable lt list gt Specify messages not to be placed in queue Note 5 DISable Read the disabled messages CLEar Clear messages from error queue Parameters lt NDN gt Bxx x Binary format each x 1 or 0 Hx Hexadecimal format x 0 to FFFF Qx Octal format x 0 to 177777 lt NRf gt 0 to 65535 Decimal format lt list gt 100 200 224 Example of a range and single entry 100 through 200 and 224 Notes 1 Commands in this subsystem are not affected by RST or SYSTem PRESet The effects of cycling power CLS and STATus PRESet are explained by the following notes vAN Event registers
272. oper parameter syntax for setting bits B5 B3 and B2 b101100 Binary format lt NDN gt parameter type h2C Hexadecimal format lt NDN gt parameter type q54 Octal format lt NDN gt parameter type 44 Decimal format lt NRf gt parameter type Valid characters for the non decimal parameter values are shown as follows lt NDN gt Format __ Valid Characters Binary 1 s and 0 s Hexadecimal 0 through 9 and A through F Octal 0 through 7 13 6 Status Structure Figure 13 2 A Bits 0 through 7 16 bit status register Bit Position B7 B6 B5 B4 B3 B2 B1 BO Binary Value 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 Decimal Weights 128 64 32 16 8 4 2 1 2 2 2 2 2 27 2 2 B Bits 8 through 15 Bit Position B15 B14 B13 B12 B11 B10 B9 B8 Binary Value 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 Decimal Weights 32768 16384 8192 4096 2048 1024 512 256 27 2 25 2 27 2 2 2 Reading registers Any register in the status structure can be read by using the appropriate query command The following explains how to interpret the returned value response message The actual query commands are covered later in this section see Tables 13 3 through 13 6 The response message will be a value that indicates which bits in the register are set That value if not already binary will have to be converted to its binary equivalent For exa
273. operation will keep looping around in the trigger layer until 10 measurements are performed If the arm count is set to 2 operation will then loop back through the arm layer and go back into the trigger layer to perform 10 more measurements Trigger model configuration front panel NOTE See SCPI Programming Table 9 2 for the SCPI commands to configure the trig ger model There are two separate configuration menus to configure the trigger model one for the arm layer and one for the trigger layer Note that trigger delay can be set from either the trigger layer configuration menu or from the DELAY key Once in a menu structure use the A and w keys to display menu items Use the cursor and p and the a and y keys to key in values A menu item or value is selected by pressing ENTER Use the EXIT key to exit from the menu Arm layer configuration menu The configuration menu for the arm layer is structured as follows Bullets denote the main items of the menu To access the menu press SHIFT and then CONF ARM e ARM IN Select the Arm in control source IMM Immediate GPIB TIMER MAN Manual TLINK STEST TEST or BSTEST 1 TIMER You will be prompted to enter the timer interval in hour minute sec ond format The TIMER annunciator will turn on The minimum timer setting is 0 001 seconds 2 TLINK Select the input trigger link line 1 to 6 You will then be prompted to enable ONCE or disable N
274. or disable autorange see Note vV SCPI Reference Tables 17 7 Table 17 4 cont SENSe command summary Default Command Description parameter Ref SCPI ULIMit lt NRf gt Select autorange upper limit 0 021 to 2 le 2 0 021 amps ULIMit Query upper limit for autorange LLIMit lt NRf gt Select autorange lower limit 0 021 to 0 021 2 le 11 amps LLIMit Query lower limit for autorange AUTO Query state of autorange V DAMPing lt b gt Enable or disable current damping OFF Sec 4 DAMPing Query state of damping RESistance Path to configure ohms function vV NPLCycles lt NRf gt Set integration rate in line cycles PLC 0 01 to 6 60Hz Sec 6 vV 10 5 50Hz NPLCycles Query NPLC vV RANGe Configure measurement range Sec 6 vV UPPer lt NRf gt Select range 0 to 2 1e11 ohms 2 le5 Vv UPPer Query range value vV AUTO lt b gt Enable or disable autorange see Note Vv ULIMit lt NRf gt Select autorange upper limit 2 le11 to 2 lell 2 1e11 ohms ULIMit Query upper limit for autorange LLIMit lt NRf gt Select autorange lower limit 2 1e11 to 2 le3 2 1e11 ohms LLIMit Query lower limit for autorange AUTO Query state of autorange vV GUARd lt b gt Enable or disable driven guard OFF Sec 3 GUARd Query state of driven guard CHARge Path to configure coulombs function vV NPLCycles lt NRf gt Set integration rate in line cycles PLC 0 01 to 6 60Hz Sec
275. ored readings and buffer statistics i Press RCLL The message RDG NO 1 is displayed Note that the arrow annunciator lt gt also turns on to indicate that additional data is available for viewing As shown in Figure 8 1 use the RANGE keys A and y and the cursor keys lt p to nav igate through the reading numbers reading values timestamps and buffer statistics To return to the normal display press EXIT Buffer 8 3 Figure 8 1 Buffer locations RDG NO 10 Reading Value Timestamp RDG NO 9 Reading Value Timestamp RDG NO 8 Reading Value Timestamp RDG NO 7 Reading Value Timestamp RDG NO 6 Reading Value Timestamp RDG NO 5 Reading Value Timestamp RDG NO 4 Reading Value Timestamp a RDG NO 3 Reading Value Timestamp RANGE RDG NO 2 Reading Value Timestamp RDG NO al Reading Value Timestamp RANGE STD DEV Standard Deviation Value v Average Average Value Pk Pk Peak to Peak Value Min At XX Minimum Value Timestamp Max At XX Maximum Value Timestamp e Buffer statistics e MIN and MAX provides the minimum and maximum readings stored in the buffer It also indicates the buffer location of these readings e The PK PK peak to peak value is the difference between the maximum and mini mum readings stored in the buffer PK PK MAX MIN e Average is the mean of the buffer readings Mean is calculated as follows n Xi Y j 1 Eg Where X is a stored reading n is the number of stored reading
276. ould then be displayed Voisp Veer KT q n Ireav lo In per To kT q In Ikeap ireL 0 26 1 dn Ikeap ireL 25 C NOTE Thecircuit topology of Figure 11 9 works for positive input currents only For bipolar input signals an external offset bias must be applied or use a PNP transistor for Q1 Non decade current gains Figure 11 10 Non decade current gains Input Model 6514 electrometer input uses internal decade resistance feedback networks for the current ranges In some applications non decade current gains may be desirable As shown in Figure 11 10 an external feedback resistor Rpg can be used to serve this purpose Limitations on the magnitude of the feedback current require that the value of Rpg be greater than 10 Q Zero Input 10mg Check Current gt r MN LO To Ranging Amplifier COM gt i NN f I OpAmp gt r 7 Preamp Chassis Digital 1 0 Analog Outputs and External Feedback 11 17 SCPI programming external feedback Table 11 4 SCPI commands external feedback Commands Description Ref Default SENSe SENSe Subsystem VOLTage Volts configuration XFEedback lt b gt Enable or disable external feedback Off FUNCtion VOLTage Select Volts function Sec 3 SYSTem SYSTem Subsystem ZCHeck lt b gt Enable or disable zero check Sec 2 On Programming example external feedback The following command sequence config
277. ould be purchased only through Keithley Instruments to maintain accuracy and functionality of the product If you are unsure about the applicability of a replacement component call a Keithley Instruments office for information To clean an instrument use a damp cloth or mild water based cleaner Clean the exterior of the instrument only Do not apply cleaner directly to the instrument or allow liquids to enter or spill on the instrument Products that consist of a circuit board with no case or chassis e g data acquisition board for installation into a computer should never require cleaning if handled accord ing to instructions If the board becomes contaminated and operation is affected the board should be returned to the factory for proper cleaning servicing Table of Contents 1 Getting Started General information cceeeseeseeecsseeseeeceececeeeeecnecneeaeesesseeateees 1 2 Warranty information 0 0 cece eeeeeeceeeseceececeteceseeceeeeceaeeeneeees 1 2 Contact information eee eeeeceeseeeee cesses ceesaeeneesaeenees 1 2 Safety symbols and terms 20 0 cc eeeseseseeeecseeeeeeeeseeeeeeeeneens 1 2 TS PO CHO sides ccses hi sacs das evib dene ne Sabedbes cavebedbneeereetenbavtouastine 1 2 Options and accessories oo eee eee eeeeeecseceseceeceteteeeeeeeeeeeaes 1 3 System electrometer features 0 0 eee cesses ceeceeeceeeeeeeeeeeees 1 4 Front and rear panel familiarization eee eee eeeeeeeeeeee ees 1 5 Front panel summary
278. peat steps 3 through 13 for the 20V and 200V ranges using Table 19 3 as a guide Table 19 3 Volts calibration summary Model 6514 range Calibrator voltages 2V 20V 200V Triax short 2 000000V 2 000000V Triax short 20 00000V 20 00000V Triax short 200 0000V 200 0000V Calibrate zero positive full scale and negative full scale for each range 19 10 Calibration Amps calibration 20pA 20mA range calibration Figure 19 2 Connections for 20uA 20mA range calibration 1 Connect the triax shielding cap to the Model 6514 INPUT jack Low noise Coax BNC Cable Model 6514 Electrometer BN C to dual DC Current Calibrator Banana Plug Adapter Connect Cable Shield to Output LO ma 10 11 12 13 14 Select Model 6514 amps function by pressing the I key and set the calibrator to output DC current Select Model 6514 20uA range and make sure the calibrator output is turned on Press SHIFT then CAL then press ENTER at the CAL RUN prompt The unit will prompt for the zero calibration point 20uA ZERO Connect the triax shielding cap to the INPUT jack allow 15 seconds for settling and then press ENTER Connect the current calibrator to the Model 6514 INPUT jack as shown in Figure 19 2 The unit will prompt for the positive full scale cal point 20uA CAL Press ENTER The unit will prompt for the positive full scale current 20 00000 uA
279. properly warmed up and connected to Model 6514 INPUT jack e Always allow the source signal to settle before calibrating each point e Do not connect test equipment to Model 6514 through a scanner or other switching equipment e If an error occurs during calibration Model 6514 will generate an appropriate error message WARNING Themaximum common mode voltage voltage between common and chas sis ground is 500V peak DC to 60Hz sine wave E xceeding this value may cause a breakdown in insulation creating a shock hazard CAUTION Themaximum input voltage is 250V peak DC to 60Hz sine wave E xceed ing this voltage may result in instrument damage Calibration cycle Perform calibration at least once a year to ensure the unit meets or exceeds its specifications Recommended calibration equipment Table 19 1 lists the recommended equipment for the calibration procedures You can use alternate equipment but keep in mind that test equipment uncertainty will affect calibration accuracy Calibration equipment should have accuracy specifications at least four times better than corresponding Model 6514 specifications 19 4 Calibration Table 19 1 Recommended calibration equipment Description Manufacturer model Specifications Calibrator Resistance calibrator Calibration standard Triax cable Low noise coax cable Triax to BNC adapter Triax shielding cap adapter Triax to alligator clip cable3
280. put cables When making precision measurements you should always use low noise cables The follow ing low noise cables are recommended for use with Model 6514 e Model 237 ALG 2 This 2 meter low noise triax cable mates directly to the input con nector of Model 6514 The other end is terminated with three alligator clips The clip with the red boot is input high black boot is input low or guard and the green boot is chassis ground e Model 7078 TRX 3 This 3 foot low noise triax cable is terminated with a 3 slot triax connector on either end e Models 7078 TRX 10 and 7078 TRX 20 Same as Model 7078 TRX 3 except that they are 10 feet and 20 feet in length NOTE Asa general rule always use the shortest possible cable for volts amps and ohms measurements 2 6 Measurement Concepts Basic connections to DUT Unguarded connections Basic unguarded connections are shown in Figure 2 3 the DUT is the voltage current resis tance or charge to be measured Circuit high is connected to the center conductor of the input connector and circuit low is connected to the inner shell of the connector For unguarded volts and ohms measurements the driven guard GRD must be off Figure 2 3 HI Basic connections for unguarded measurements INPUT 250V PK NOTE For Volts and Ohms GRD must be off Figure 2 4 Shielding for unguarded measurements M easurement Concepts 2 7 Noise and safety shields
281. que to a particular measurement function are covered in Sections 3 4 and 5 Table 2 5 located at the end of Section 2 lists all measurement considerations and indicates where to find detailed information on them For comprehensive information on all measurement considerations refer to the Low Level Measurements handbook which is available from Keithley Ground loops Ground loops that occur in multiple instrument test setups can create error signals that cause erratic or erroneous measurements The configuration shown in Figure C 1 introduces errors in two ways Large ground currents flowing in one of the wires will encounter small resistances either in the wires or at the connecting points This small resistance results in voltage drops that can affect the measurement Even if the ground loop currents are small magnetic flux cutting across the large loops formed by the ground leads can induce sufficient voltages to disturb sen sitive measurements Figure C 1 Signal Leads Power line ground loops Instrument 1 Instrument 2 Instrument 3 oS oe A Ground Loop w Current Power Line Ground General M easurement Considerations C 3 To prevent ground loops instruments should be connected to ground at only a single point as shown in Figure C 2 Note that only a single instrument is connected directly to power line ground Experimentation is the best way to determine an acceptable arrangement For this pur pose
282. quire readings Use INITiate to start trigger the measurement process send ABORt to abort the measurement process and then use SENSe DATA LATest to return the last latest reading D MEASuref lt function gt Configure and perform one shot measurement lt function gt VOLTage DC Measure voltage CURRent DC Measure current RESistance Measure resistance CHARge Measure charge This command combines all of the other signal oriented measurement commands to perform a one shot measurement and acquire the reading When this command is sent the following commands execute in the order that they are presented e CONFigure lt function gt e READ When CONFigure is executed the instrument goes into a one shot measurement mode See CONFigure for details 15 4 SCPI Signal O riented Measurement Commands When READ is executed its operations will then be performed In general an INITiate is executed to perform the measurement and a FETch is executed to acquire the reading See READ for details NOTE Ifyou send MEASure no measurement function specified the operations of CONFigure will apply to the presently selected function DISPlay FO RM at and SYSTem e DISPlay subsystem Covers the SCPI commands that are used to control the display e FOR Mat subsystem Covers the SCPI commands to configure the format that read ings are sent over the bus e SYSTem subsystem Covers miscel
283. r all errors status code and message COUNt Read the number of messages in queue CODE Code numbers only NEXT Read and clear oldest error status code only ALL Read and clear all errors status codes only CLEar Clear messages from error queue Notes 1 Power up and CLS empties the error queue STATus PRESet has no effect 2 Power up enables error messages and disables status messages CLS and STATus PRESet have no effect Programming example read error queue The following command reads the error queue STAT QUE Read Error Queue Common Commands 14 2 Common Commands Common commands summarized in Table 14 1 are device commands that are common to all devices on the bus These commands are designated and defined by the IEEE 488 2 standard Table 14 1 IEEE 488 2 common commands and queries Mnemonic Name Description Ref CLS Clear status Clears all event registers and error queue Sec 13 ESE lt NRf gt Event enable command Program the standard event enable register Sec 13 ESE Event enable query Read the standard event enable register Sec 13 ESR Event status register query Read the standard event enable register and clear it Sec 13 IDN Identification query Returns the manufacturer model number serial A number and firmware revision levels of the unit OPC Operation complete command Set the operation complete bit in the standard event B register after all pending commands ha
284. r test fixtures The American National Standards Institute ANSI states that a shock hazard exists when voltage levels greater than 30V RMS 42 4V peak or 60VDC are present A good safety practice is to expect that hazardous voltage is present in any unknown circuit before measuring Operators of this product must be protected from electric shock at all times The responsible body must ensure that operators are prevented access and or insulated from every connection point In some cases connections must be exposed to potential human contact Product operators in these circumstances must be trained to protect themselves from the risk of electric shock If the circuit is capable of operating at or above 1000 volts no conductive part of the circuit may be exposed Do not connect switching cards directly to unlimited power circuits They are intended to be used with impedance limited sources NEVER connect switching cards directly to AC mains When connecting sources to switching cards install protective devices to limit fault current and voltage to the card Before operating an instrument make sure the line cord is connected to a properly grounded power receptacle Inspect the connecting cables test leads and jumpers for possible wear cracks or breaks before each use When installing equipment where access to the main power cord is restricted such as rack mounting a separate main input power disconnect device must be provided in close proximity
285. r w key to display the present address i e ADDR 14 3 Use the lt gt A and y keys to display a valid address value and press ENTER 4 Return to the main display by pressing EXIT General bus commands Commands and associated statements General commands are those commands such as DCL that have the same general meaning regardless of the instrument Table 12 1 lists the general bus commands Table 12 1 General bus commands Command _ Effect on Model 6514 REN Goes into remote when next addressed to listen IFC Reset interface all devices go into talker and listener idle states LLO LOCAL key locked out GTL Cancel remote restore front panel operation for Model 6514 DCL Return all devices to known conditions SDC Returns Model 6514 to known conditions GET Initiates a trigger SPE SPD Serial polls Model 6514 REN remote enable The remote enable command is sent to Model 6514 by the controller to set up the instrument for remote operation Generally the instrument should be placed in the remote mode before you attempt to program it over the bus Simply setting REN true does not actually place the instru ment in the remote state You must address the instrument to listen after setting REN true before it goes into remote Note that the instrument does not have to be in remote to be a talker Also note that all front panel controls except for LOCAL and POWER are inoperative while the instrument is
286. rOCU CHOI s aaa N E H 2 Reading calibration standard values eeeesceeseceeeeeeseeeneeeeees H 2 Data transfer connections ccccccccceeesseecececesseteceeceeeaeee H 2 Reading Values epossen seineg eaea EEan H 2 Example program o ccssisescsscesscsssssscsssesseevcgees ssensssevessuresesses H 3 Remote Calibration ccccccccccsssscccceesesecececesessseeccecessaeeeeceessaees H 4 Calibration commands ccccccssccceceeesssecececessnteeeeceesaees H 4 Remote calibration overview ccccccccccccesesceceesesesesesesseees H 4 List of Illustrations 1 Figure 1 1 Figure 1 2 2 Figure 2 1 Figure 2 2 Figure 2 3 Figure 2 4 Figure 2 5 Figure 2 6 Figure 2 7 Figure 2 8 Figure 2 9 Figure 2 10 3 Figure 3 1 Figure 3 2 Figure 3 3 Figure 3 4 Figure 3 5 Figure 3 6 Figure 3 7 Figure 3 8 Figure 3 9 4 Figure 4 1 Figure 4 2 Figure 4 3 Figure 4 4 Figure 4 5 Figure 4 6 Figure 4 7 Figure 4 8 Figure 4 9 Getting Started Model 6514 front panel o eee eeeeceseeeeeeceeceeeseeseenecneeeeeaeens 1 5 Model 6514 rear panel 0 eee eee cee eeeceeeeeeecaeeeeeeeeeneenaes 1 8 Measurement Concepts Input connector Configurations 0 eeceeeeeeeeeeeeeeeeseeenees 2 4 Maximum input levels oo eee csesecsseeseceeceeceeeeeeseeeeees 2 5 Basic connections for unguarded measurements 2 6 Shielding for unguarded measurements eee eeeeeeees 2 7 Basic connections for guarded mea
287. ral M easurement Considerations Electrochemical effects Error currents also arise from electrochemical effects when ionic chemicals create weak bat teries on a circuit board These batteries could generate a few nanoamps of current between con ductors Ionic contamination may be the result of body oils salts or solder flux The problem is further enhanced by high humidity moisture that decreases insulation resistance When building test fixtures select insulators that resist water absorption and use the fixture in a moderate humidity environment Also be sure that all insulators are kept clean and free of contamination See Handling and Cleaning Test Fixtures in Section 2 for cleaning tips Humidity Light Excess humidity can reduce insulation resistance on PC boards and in test connection insu lators Reduction in insulation resistance can of course seriously affect high impedance mea surements Also humidity moisture can combine with contaminants to produce offset currents caused by electrochemical effects see Electrochemical Effects To minimize the effects of moisture keep humidity to a minimum ideally lt 50 and keep components and connectors in the test system clean See Handling and Cleaning Test Fixtures in Section 2 for cleaning tips Some components such as semiconductor junctions and MOS capacitors on semiconductor wafers are excellent light detectors Consequently these components must be test
288. ral purpose are summarized in Table F 1 Table F 1 IEEE 488 bus command summary State of Command ATN type Command line Comments Uniline REN Remote Enable X Set up devices for remote operation EOI X Marks end of transmission IFC Interface Clear X Clears interface ATN Attention Low Defines data bus contents SRQ X Controlled by external device Multiline LLO Local Lockout Low Locks our local operation Universal DCL Device Clear Low Returns device to default conditions SPE Serial Enable Low Enables serial polling SPD Serial Poll Disable Low Disables serial polling Addressed SDC Selective Device Clear Low Returns unit to default conditions GTL Go To Local Low Returns device to local Unaddressed UNL Unlisten Low Removes all listeners from the bus UNT Untalk Low Removes any talkers from the bus Common High Programs IEEE 488 2 compatible instruments for common operations SCPI High Programs SCPI compatible instru ments for particular operations EEE 488 Bus Overview F 8 ae 1 U0d X 801A 4d 7 TOIA A ON YTS9 BPOW Aq pauaw jdu JOU TOULNOOD IAY LOL pue GYNDIYNOONN 110d TATIVeVd Ndd AYNDISNOD 110d HTIVYVYd Dddx Das 90d dnoud dnowd GNVWWOD GNVWWOD AYVGNODAS AYY NIYd OW 9v1 90N 99V dNOYD dnowd dnowd dnowd ssaygav ss3yady GNVWWOD ONVWWOD XYL Naisn AVSYSAINO _ aassayqav aq o inn ST Oo INN ST sn IS ST TET eT
289. ranges damping off 3s typical on pA ranges damping on 15ms on nA ranges 5ms on pA and mA ranges NMRR gt 95dB on pA 60dB on nA pA and mA ranges at 50Hz or 60Hz 0 1 Digital Filter 40 Specifications OHMS ACCURACY TEMPERATURE 1Year 1 COEFFICIENT TEST 5 DIGIT 18 28 C 0 18 C amp 28 50 C CURRENT RANGE RESOLUTION rdg counts rdg counts C nominal 2 kQ 10mQ 0 20 10 0 01 2 0 9 mA 20 kQ 100 ma 0 15 3 0 01 1 0 9 mA 200 kQ 1 Q 0 25 3 0 01 1 0 9 mA 2 MQ 10 Q 0 25 4 0 02 2 0 9 pA 20 MQ 100 Q 0 25 3 0 02 1 0 9 pA 200 MO 1 kQ 0 3043 0 02 1 0 9 pA 2 GQ 10 kQ 1 5 4 0 04 2 0 9 nA 20 GQ 100 kQ 15 3 0 0441 0 9 nA 200 GQ 1MQ 1 5 3 0 04 1 0 9 nA 1 When properly zeroed 5 digit Rate Slow 100ms integration time MAXIMUM OPEN CIRCUIT VOLTAGE 250VDC PREAMP SETTLING TIME To 10 of final reading with lt 100pF input capacitance 2kQ through 200kQ 2ms 20MQ through 200MQ 90ms 2GQ through 200GQ 1s COULOMBS ACCURACY TEMPERATURE 1 Year 1 2 COEFFICIENT 6 DIGIT 18 28 C 0 18 C amp 28 50 C RANGE RESOLUTION rdg counts rdg counts C 20 nC 10 fC 0 4 50 0 04 10 200 nC 100 fC 0 4 50 0 04 10 2 uC 1pC 1 50 0 05 10 20 uC 10pC 1 50 0 05 10 Notes 1 Charge acquisition time must be lt 1000s derate 2 for each additional 10 000s 2 When properly zeroed 6 digit Rate Slow 100ms integration time INPUT BIAS CURRENT lt 4fA at Tcay Temperature coefficient 0 5fA
290. ranges are calibrated send the commands to program the calibra tion dates for example CAL PROT DATE 1998 12 15 CAL PROT NDUE 1999 12 15 7 Finally send the following commands to save calibration constants and then lock out calibration CAL PROT SAVE CAL PROT LOCK Index Numerics 20uA 20mA range accuracy 18 12 200MQ 200GQ range accuracy 18 17 20pA 2uA range accuracy 18 13 2kQ 20MQ range accuracy 18 15 2V analog output 11 7 Aborting calibration 19 5 Address commands F 9 Addressed multiline commands F 9 Amps calibration 19 10 Amps measurement accuracy 18 12 Amps measurement considerations 4 9 Amps measurement procedure 4 2 Amps Measurements 4 1 Analog outputs 11 7 Application 3 14 5 7 Applications 4 13 Auto discharge 5 2 Automatic calculations 19 6 Autozero 2 2 Basic connections to DUT 2 6 Binning 10 4 Buffer 8 1 Buffer operations 8 2 Buffer statistics 8 3 Bus commands F 7 Bus description F 3 Bus lines F 5 Bus management lines F 5 Cable insulation resistance 4 14 Cable leakage resistance 3 9 Calibration 19 1 Calibration commands H 4 Calibration considerations 19 3 Calibration cycle 19 3 Calibration errors 19 5 Calibration menu 19 5 Calibration Options H 1 Calibration procedure 19 7 Calibrator voltage calculations 18 7 Capacitance measurements 5 7 Capacitor dielectric absorption 3 14 Capacitor leakage current 4 14 Changing function and range E 2 Changing the calibration code 19 1
291. reading length 14 status PRINT reading Example Programs E 3 O ne shot triggering Other instruments generally have two types of triggering one shot and continuous In one shot each activation of the selected trigger source causes one reading In continuous the instru ment is idle until the trigger source is activated at which time it begins taking readings at a spec ified rate Typical trigger sources are JEEE 488 talk e JEEE 488 Group Execute Trigger GET e X command e External trigger rear panel BNC Arming the instrument to respond to triggers is implicit in the non SCPI voltmeters Sending a command to a non SCPI voltmeter to change any of the trigger controls causes the instrument to arm itself for triggers The SCPI trigger model implemented in the Model 6514 gives e Explicit control over the trigger source the TRIGger subsystem e A way for completely disabling triggers Changing any of the settings in the TRIGger subsystem does not automatically arm the Model 6514 for triggers The following program sets up the Model 6514 to take one reading each time it receives an external trigger pulse For QuickBASIC 4 5 and CEC PC488 interface card edit the following line where the QuickBASIC libraries are on your computer SINCLUDE c qb45 ieeegb bi Initialize the CEC interface as address 21 CALL initialize 21 0 Puts trigger model in idle state and configur
292. rease the leakage resistance resulting in excessive leakage currents Contami nants on DUT and test circuit components can create a leakage path The leakage currents may be large enough to corrupt low level measurements Handling tips Do not touch the bodies of DUT or test circuit components If you cannot handle them by their leads use clean cotton gloves to install them in the test fixture e Do not touch any connector or terminal insulator e If installing a test circuit that is on a PC board handle the board by the edges Do not touch any board traces or components Cleaning tips e Use dry nitrogen gas to clean dust off connector and terminal insulators DUT and other test circuit components e If you have just built the test fixture remove any solder flux using methanol along with clean foam tipped swabs or a clean soft brush Clean the areas as explained in the next tip e To clean contaminated areas use methanol and clean foam tipped swabs After cleaning a large area you may want to flush the area with methanol Blow dry with dry nitrogen gas e After cleaning the test fixture and any other cleaned devices or test circuits should be allowed to dry in a 50 C low humidity environment for several hours M easurement Concepts 2 11 Input protection Model 6514 incorporates protection circuitry against nominal overload conditions However a high voltage gt 250V and resultant current surge could damage the inpu
293. rements from 100aA to 21mA using 10 measurement ranges 20pA 200pA 2nA 20nA 200nA 2uA 20uA 200HA 2mA and 20mA External feedback The external feedback mode of Model 6514 can be used to measure logarithmic currents and re configure the input to use non decade current ranges Measure ments using the external feedback mode are covered in Section 11 NOTE Accuracy specifications for all measurement functions are provided in Appendix A Amps measurement procedure CAUTION Themaximum input voltage and current to M odel 6514 is 250V peak and 21mA E xceeding either of these values may cause damage to the instru ment that is not covered by the warranty WARNING Themaximum common mode input voltage which is the voltage between theinput HI or LO and chassis ground is 500V peak E xceeding this value may create a shock hazard To achieve optimum precision for low level current measurements input bias current and voltage burden can be minimized by performing the offset correction procedures in Section 19 Information about these offsets are provided in Current Measurement Considerations located in this section NOTE After measuring high voltage or high ohms it may take several minutes for the input current to drop to within specified limits Input current can be verified by placing the protection cap on the input triax connector and then installing the ground link between COMMON and CHASSIS ground With the instrument o
294. rent sink capacity of the output driver allows direct control of relays solenoids and lamps no additional circuitry needed As shown in Figure 11 2 each of the four digital open collector outputs includes a built in pull up resistor to 5V The output transistor is capable of sinking 500mA from voltages up to 33V Each output channel contains a fly back diode for protection when switching inductive loads such as a low power solenoid or relay coils To use these fly back diodes connect the external supply voltage to pin 5 of the digital I O port Make sure the external supply voltage is between 5V and 33V and the current required by the device does not exceed 500mA 11 4 Digital I O Analog O utputs and External Feedback CAUTION Do not exceed 33V maximum voltage on pin 5 of the digital I O port and do not use any output line to sink gt 500mA Exceeding these limits may cause damage to the instrument that is not covered by the warranty An externally powered relay connected to the digital output port is shown in Figure 11 3 Other externally powered devices can be similarly connected by replacing the relay with the device When the output line is set LO OV the output transistor sinks current through the exter nal device In the HI state the output transistor is off transistor switch open This interrupts current flow through the external device Figure 11 3 Controlling externally powered relays
295. representative or call one of our Application Engineers at 1 800 348 3735 U S and Canada only Safety symbols and terms The following symbols and terms may be found on the instrument or used in this manual The A symbol on an instrument indicates that the user should refer to the operating instruc tions located in the manual The A symbol on the instrument shows that high voltage may be present on the termi nal s Use standard safety precautions to avoid personal contact with these voltages The WARNING heading used in this manual explains dangers that might result in personal injury or death Always read the associated information very carefully before performing the indicated procedure The CAUTION heading used in this manual explains hazards that could damage the instru ment Such damage may invalidate the warranty Inspection Model 6514 was carefully inspected electrically and mechanically before shipment After unpacking all items from the shipping carton check for any obvious signs of physical damage that may have occurred during transit There may be a protective film over the display lens which can be removed Report any damage to the shipping agent immediately Save the original packing carton for possible future shipment The following items are included with every Model 6514 order e Model 6514 System Electrometer with line cord e Model 237 ALG 2 triax cable e Accessories as ordered e Certificate of calibra
296. rge ranges Measurements using the external feedback mode are covered in Section 11 NOTE Accuracy specifications for all measurement functions are provided in Appendix A Auto discharge Model 6514 has an auto discharge feature for the coulombs function When enabled auto dis charge resets the charge reading to zero when the specified charge level is reached After the inte grator resets the charge measurement process simply restarts at zero The charge reading resets every time the specified charge level is reached When auto discharge is disabled you can use zero check to reset the integrator Perform the following steps to set an auto discharge level and enable it 1 Press SHIFT and then AUTO DIS to display the present auto discharge level Use the cursor keys lt and p and A and Y to enter a discharge level To change polar ity place the cursor on the or sign and press A or y To change range place the cursor on the range indicator and use the A and y keys 3 With the desired auto discharge level displayed press ENTER NOTE Pressing SHIFT and then AUTO DIS a second time disables auto discharge DISCHRG OFF displayed briefly Coulombs M easurements 5 3 Coulombs measurement procedure CAUTION Themaximum input voltage and current to M odel 6514 is 250V peak and 21mA E xceeding either of these values may cause damage to the instru ment that is not covered by the warranty WARNING The max
297. ring Table 9 1 Auto delay settings Volts Amps Ohms Coulombs Range Delay Range Delay Range Delay Range Delay 2V Sms 20pA 2500ms 2kQ Sms 20nC 3ms 20V 3ms 200pA 2500ms 20kQ lms 200nC 3ms 200V 2ms 2nA 10ms 200kQ lms 2uC 3ms 20nA 10ms 2MQ 10ms 20uC 3ms 200nA 10ms 20MQ 10ms 2uA 10ms 200MQ 10ms 20uA 5ms 2GQ 50ms 200uA 5ms 20GQ 50ms 2mA lms 200GQ 50ms 20mA 0 5ms Measure action The measure action block of the trigger model is where a measurement is performed How ever if the repeating filter is enabled see Figure 9 3 the instrument samples the specified num ber of reading conversions to yield single filtered reading Only one reading conversion is performed if the digital filter is disabled or after the specified number of reading conversions for a moving average filter is reached Figure 9 3 Measure Action Measure action block of trigger model a Filter Process S CONV e CONV CONV Reading Conversion O utput triggers Model 6514 can send out an output trigger via the rear panel TRIGGER LINK connector right after the measure action and or when operation leaves the trigger layer An output trigger can be used to trigger another instrument to perform an operation e g select the next output step for a source Triggering 9 7 Counters Programmable counters are used to repeat operations within the trigger model layers For example if the trigger count is set for 10
298. rn to normal display 19 20 Calibration Displaying the calibration count To display the calibration count at any time 1 From normal display press SHIFT then CAL The unit will display the following CAL RUN 2 Use either RANGE key to select CAL COUNT from the calibration menu then press ENTER For example COUNT 1 3 Press EXIT to return to normal display Routine M aintenance 20 2 Routine Maintenance Introduction The information in this section deals with routine type maintenance that can be performed by the operator and includes procedures for setting the line voltage and replacing the line fuse and running the front panel tests Setting line voltage and replacing line fuse WARNING Disconnect the line cord at the rear panel and remove all test leads con nected to the instrument front and rear before replacing the line fuse The power line fuse is located in the power module next to the AC power receptacle see Fig ure 20 1 If the line voltage must be changed or if the line fuse requires replacement perform the following steps 1 Place the tip of a flat blade screwdriver into the power module by the fuse holder assem bly see Figure 20 1 Gently push in and to the left Release pressure on the assembly and its internal spring will push it out of the power module 2 Remove the fuse and replace it with the type listed in Table 20 1 CAUTION For continued protection against fire or instrument dam
299. rom other instruments as required for your application 4 Make sure that the other end of the cable is properly connected to the controller Most controllers are equipped with an IEEE 488 style connector but a few may require a dif ferent type of connecting cable See your controllers instruction manual for information about properly connecting to the IEEE 488 bus NOTE You canonly have 15 devices connected to an IEEE 488 bus including the controller The maximum cable length is either 20 meters or two meters times the number of devices whichever is less Not observing these limits may cause erratic bus operation Primary address selection Model 6514 ships from the factory with a GPIB address of 14 When the instrument powers up it momentarily displays the primary address You can set the address to a value of 0 30 Do not assign the same address to another device or to a controller that is on the same GPIB bus Usually controller addresses are 0 or 21 but see the controllers instruction manual for details Make sure the address of the controller is the same as that specified in the controllers program ming language The primary address is checked or changed from the GPIB menu which is accessed by press ing SHIFT and then GPIB Press the A or y key to display the present address i e ADDR 14 12 8 Remote O peration To change the GPIB address 1 Press SHIFT and then GPIB to access the GPIB configuration menu 2 Use the a o
300. rough 17 9 list the SCPI confirmed commands and the non SCPI commands implemented by the Model 6514 Table G 1 IEEE 488 documentation requirements R equirements Description or reference 1 2 3 4 5 a b c d e 6 7 8 9 10 11 12 13 14 IEEE 488 Interface Function Codes Behavior of 6514 when the address is set outside the range 0 30 Behavior of 6514 when valid address is entered Power On Setup Conditions Message Exchange Options Input buffer size Queries that return more than one response message unit Queries that generate a response when parsed Queries that generate a response when read Coupled commands Functional elements required for SCPI commands Buffer size limitations for block data Syntax restrictions Response syntax for every query command Device to device message transfer that does not follow rules of the standard Block data response size Common Commands implemented by 6514 Calibration query information Trigger macro for DDT See Appendix F Cannot enter an invalid address Address changes and bus resets Determine by SYSTem POSetup Section 16 2048 bytes None All queries Common Commands and SCPI None See Table G 2 Contained in SCPI command sub systems tables see Tables 17 1 through 17 9 Block display messages 12 char acters max See Programming Syntax in Section 12
301. round Guard plate A metal guard plate will provide guarding or noise shielding for the DUT or test circuit It will also serve as a mounting panel for DUT or test circuits The guard plate must be insulated with 1000V spacing from the chassis of the test fixture 2 10 Measurement Concepts Connectors terminals and internal wiring Basic connector requirements include a 3 lug female triax connector and three banana jacks One banana jack is used to make the COMMON connection to the electrometer for guarded measurements The other two banana jacks will accommodate connection to an external power supply The banana jacks must be insulated from the chassis of the test fixture The outer shell of the triax connector must be referenced to chassis ground Therefore DO NOT insulate the outer shell of the triax connector from the metal chassis of the test fixture DUT and test circuits are to be mounted on the guard plate using insulated terminals To min imize leakage select terminals that use virgin Teflon insulators Inside the test fixture use an insulated wire to connect the inner shell of the triax connector to the guard plate For unguarded measurements the guard plate will serve as a noise shield For the volts and ohms functions turning GRD on will connect guard to the guard plate Handling and cleaning test fixtures Dust body oil solder flux and other contaminants on connector and terminal insulators can significantly dec
302. rvice M aster Summary Staus I7 17 OSB Operation Summary Bit Always Zero 15 15 Note RQS bitis in serial poll byte ESR ESE lt N Rf gt MSS bit is in STB response ESE Measurement Event Registers Operation Event Registers Condition Event Event Enable Conditi A 7 ondition Event Event Enable Register Register Register Register Register Register 0 0 0 Calibrating Cal Cal Low Limit 1 Fail LL1F LL1F LL1F High Limit 1 Fail HLIF HL1F HL1F 9 Low Limit 2 Fail LL2F LL2F LL2F L_ High Limit 2 Fail HL2F HL2F HL2F y Limits Pass LP LP LP s Trigger Layer Reading Available RAV RAV O RAV Logical Arm Layer Logical Reading Overflow ROF ROF ROF OR OR Buffer Available BAV BAV BAV Buffer Full BFL BFL_ 1_BFL Z 10 10 10 y Idle TI TI TI gt 12 12 IZ 4 13 13 13 4 14 14 TF Always Zero 15 15 15 CONDition EVENt _ ENABle lt NRf gt CONDition EVENt ENABle lt NRf gt ENABle ENABle 13 4 Status Structure Clearing registers and queues When Model 6514 is turned on the bits of all registers in the status structure are clear reset to 0 and the two queues are empty Commands to reset the event and event enable registers and the error queue are listed in Table 13 1 In addition to these commands any enable register can be reset by sending the 0 parameter value with the individual command to program the regist
303. s The STD DEV value is the standard deviation of the buffered readings Standard devi ation is calculated as follows no fi n 2 Xi gt Xi i 1 i l re n 1 Where X is a stored reading nis the number of stored readings 8 4 Buffer SCPI programming Commands associated with buffer operation are listed in Table 8 1 The TRACe commands are used to store and recall readings in the buffer The FORMat ELEMents command is used to specify which data elements to include in the response message for TRACe DATA which is the command to read the buffer The CALCulate3 commands are used to obtain statistics from the buffer data NOTE The Model 6514 uses IEEE 754 floating point format for statistics calculations Table 8 1 SCPI commands buffer Commands Description Default Ref TRACe TRACe Subsystem See Note CLEar Clear readings from buffer FREE Query bytes available and bytes in use A POINts lt n gt Specify number of readings to store 1 to 2500 100 ACTual Returns number of readings actually stored in buffer FEED lt name gt Select source of readings SENSe 1 CALCulate 1 or SENS1 B CALCulate2 CONTrol lt name gt Select buffer control mode NEVer or NEXT NEV C TSTamp Timestamp FORMat lt name gt Select timestamp format ABSolute or DELTa ABS D DATA Read all readings in buffer E FORMat FORMat Subsystem Sec 16 ELEMents lt list gt Specify data elements for TRACe DATA response All 3
304. s This voltage is known as the voltage burden If the voltage burden is large in relation to the volt age of the measured circuit then significant measurement errors will occur Refer to Figure 4 4 to see how voltage burden affects current measurements Assume Vg is SmV and Rg is 5KQ to configure a 1uA current source SmV 5kQ 14A An ideal ammeter with zero voltage burden would measure the current source as follows _ Es 5mv _ 27 ua MIR oKQ 4 10 Amps Measurements In practice however every ammeter has a voltage burden If the voltage burden Vp is ImV the current will be measured as follows Vo V 2 ia E AN Y E GBA Rs 5kQ The ImV voltage burden caused a 20 measurement error Percent error in a measured read ing I due to voltage burden can be calculated as follows Ty error 100 Vs Vp The voltage burden of Model 6514 depends on the selected range see specifications Voltage burden may be reduced by performing the offset correction procedure in Section 19 Figure 4 4 Source M eter Voltage burden Den Ea E EE E EE considerations AN gt t s Np Voltage Burden Vs VB M Re Noise Noise can seriously affect sensitive current measurements The following paragraphs discuss how source resistance and input capacitance affect noise performance Source resistance The source resistance of the DUT will affect the noise performance of current measurements A
305. s the DATA command will not return the reading string until the instrument finishes and goes into the idle state NOTES The format that the reading string is returned in is set by commands in the FORMat Subsystem see Section 16 If there is no reading available when DATA is sent an error 230 will occur The READ command can be used to return fresh readings This command triggers and returns the readings See Section 15 for details C GUARd Commands Either of the two guard commands VOLTage GUARd or RESistance GUARd can be used to control the state of guard Programming example The following command sequence will perform one zero corrected voltage measurement on the 2V range RST Return to RST defaults SYST ZCH ON Enable zero check VOLT GUAR ON Enable guard FUNC VOLT Select Volts function VOLT RANG 2 Select 2V range SYST ZCOR ON Perform zero correction SYST ZCH OFF Disable zero check READ Trigger and return one reading Volts and O hms Measurements 3 9 Volts and ohms measurement considerations NOTE Since Model 6514 uses the source I measure V calculate R technique to measure resistance measurement considerations that apply to the volts function also apply to the ohms function Some considerations for making accurate volts and ohms measurements are summarized as follows Additional measurement considerations are covered in Appendix C For comprehensive i
306. s must not conflict with the address assigned to other instruments in the sys tem You can use either the SCPI or DDC language to program the instrument R S 232 interface When using the RS 232 interface you must set baud rate data bits par ity terminator and flow control For the RS 232 interface you can only use the SCPI language to program the instrument Languages For the GPIB interface there are two programming languages to choose from e SCPI language e DDC language NOTE For the RS 232 interface only the SCPI language can be used to program the instru ment When the RS 232 interface is selected it automatically defaults to SCPI SC PI language Standard Commands for Programmable Instrument SCPI is fully supported by the GPIB and RS 232 interfaces Always calibrate Model 6514 using the SCPI language DDC language Model 6514 implements most DDCs device dependent commands available in the Keithley Models 6512 617 and 617 HIQ electrometers The commands are pro vided in Appendix D See the appropriate instruction manual for details on operation Interface selection and configuration procedures When you select enable the GPIB interface the RS 232 interface disables Conversely selecting enabling the RS 232 interface disables the GPIB interface Remote O peration 12 3 NOTE When an interface is enabled on or disabled off the instrument will exit from the menu structure and perform the power on
307. s that a signal oriented measure ment command parameter has been ignored Figure 13 7 Q CONDition Warn Cal ee A uestionable event B15 B14 B13 B8 B7 B6 B0 ondition Register status a Warn Cal Questionable re 3 LEVEN B15 614 13 88 67 B6 Bo Event Register Register To QSB bit of Status Byte a OR L amp j Warn Cal Questionable Event ENABLESNR 15 614 813 88 67 86 80 Enable Register Decimal 16384 128 Weights 214 27 Warn Command Warning amp Logical AND Cal Calibration Summary OR Logical OR Condition registers As Figure 13 1 shows each status register set except the standard event register set has a condition register A condition register is a real time read only register that constantly updates to reflect the present operating conditions of the instrument For example while Model 6514 is in the idle state bit B10 Idle of the operation condition register will be set When the instru ment is taken out of idle bit B10 clears 13 16 Status Structure The commands to read the condition registers are listed in Table 13 4 For details on reading registers see Reading registers Table 13 4 Common and SCPI commands condition registers Command Description STATus STATus subsystem OPERation CONDition
308. s the source resistance is reduced the noise gain of the ammeter will increase as we will now discuss Figure 4 5 shows a simplified model of the feedback ammeter Rg and Cg represents the source resistance and source capacitance Vg is the source voltage and Vyojsz is the noise volt age Finally Rp and Cp are the feedback resistance and capacitance respectively The source noise gain of the circuit can be given by the following equation Output V yorse Input V yorsg l Rp Rs Note that as Rg decreases in value the output noise increases For example when R Rg the input noise is multiplied by a factor of two Since decreasing the source resistance can have a detrimental effect on noise performance there are usually minimum recommended source resistance values based on measurement range Table 4 2 summarizes minimum recommended Figure 4 5 Source resistance and capacitance Amps M easurements 4 11 source resistance values for various measurement ranges Note that the recommended source resistance varies by measurement range because the Rp value also depends on the measurement range Table 4 2 Minimum recommended source resistance values Minimum Recommended Range Source Resistance pA 1GQ to 100GQ nA IMQ to 100MQ uA 1kQ to 100kQ mA 1 to 100 Cs Zs Rs Q VY Current Source Model 6514 Ammeter 4 12 Amps Measurements Source capacitance DUT
309. s within the program message e When the path pointer detects a colon that immediately follows a semicolon it resets to the root level e The path pointer can only move down It cannot be moved up a level Executing a com mand at a higher level requires that you start over at the root command Using common commands and SC PI commands in the same message Both common commands and SCPI commands can be used in the same message as long as they are separated by semicolons A common command can be executed at any command level and will not affect the path pointer stat oper enab lt NRf gt ESE lt NRf gt Program Message Terminator PMT Each program message must be terminated with an LF line feed EOI end or identify or an LF EOI The bus will hang if your computer does not provide this termination The following example shows how a program message must be terminated trac poin 10 lt PMT gt Command execution rules e Commands execute in the order that they are presented in the program message e An invalid command generates an error and of course is not executed e Valid commands that precede an invalid command in a multiple command program mes sage are executed e Valid commands that follow an invalid command in a multiple command program mes sage are ignored e For fastest command execution Do not use optional command words i e SENSE 1 Do not use the colon at the beginning of a program me
310. se the digital I O port to control external circuitry Analog outputs Covers the 2V analog output and preamp out e External feedback Explains how to use the external feedback mode to perform charge and current measurements 11 2 Digital I O Analog O utputs and External Feedback Digital I O port Model 6517A s Digital I O port is a male DB 9 connector located on the rear panel The ports location and pin designations are shown in Figure 11 1 The four active low digital output lines and one input line are used to control external circuitry Figure 11 1 Model 6514 Electrometer Digital I O port ee ee OOS IEEE 488 PREAMP av COMMON CHASSIS CHANGE IEEE 250V PK OUTPUT WITH FRONT PANEL MENU omo omo oG um o o INPUT 250V PK DIGITAL vo TRIGGER LINK S232 LINE RATING 6789 DIGITAL I O Digital O utput 1 Digital O utput 2 Digital O utput 3 Digital O utput 4 EO T VEXT SOT Not Used Not Used Digital Ground Start of Test SOT and End of Test EOT are used for Limit Tests see Section 10 OANA UHBWNE tou uw to ud ut ot ue Typical applications for the digital I O port include the following e Component handler control When performing limit tests a component handler can be used to sort DUT into bins The digital I O of Model 6514 serves as the interface between the limit tests and the component handler Via the digital input l
311. sed in brackets are optional and need not be included in the program message 12 14 Remote O peration Program messages A program message is made up of one or more command words sent by the computer to the instrument Each common command is simply a three letter acronym preceded by an asterisk The following SCPI commands from the STATus subsystem are used to help explain how command words are structured to formulate program messages Command structure STATus Path Root OPERation Path ENABle lt NRf gt Command and parameter ENABle Query command PRESet Command Single command messages The above command structure has three levels The first level is made up of the root command STATus and serves as a path The second level is made up of another path OPERation and a command PRESet The third path is made up of one command for the OPERation path The three commands in this structure can be executed by sending three separate program messages as follows stat oper enab lt NRf gt stat oper enab Stat pres In each of the above program messages the path pointer starts at the root command stat and moves down the command levels until the command is executed Multiple command messages You can send multiple command messages in the same program message as long as they are separated by semicolons The following is an example showing two commands in one pro gram message stat oper stat oper e
312. sequence GPIB interface The GPIB interface is selected and configured from the GPIB menu structure From this menu you can enable or disable the GPIB interface and check or change the following settings Primary address 0 to 30 Language SCPI or DDC Selecting GPIB interface Press SHIFT and then GPIB to access the GPIB menu The present status on or off of the GPIB interface is displayed If the GPIB is already enabled on proceed to step 1 of Checking Changing GPIB Settings to check and or change the settings Perform the following steps to enable select the GPIB interface 1 Place the cursor on the OFF setting by pressing the or p key Press the a or w key to toggle the setting to ON Press ENTER The instrument will exit the menu structure and perform the power on sequence Checking changing G PIB settings Press SHIFT and then GPIB to access the GPIB menu and perform the following steps 1 Use the A or y key to display the present address ADDR and language LANG set tings If these settings are correct press EXIT to exit the menu Otherwise continue on to change one or both settings Use a or to display the primary address ADDR To retain this address press ENTER To change the GPIB address a Press the or key to move the cursor over to the address value field b Use the lt gt A and y keys to display a valid address value 0 to 30 c Press ENTER The present programmin
313. set voltage calibration 1 Access the front panel calibration menu by pressing SHIFT then CAL From the calibration menu use the up or down RANGE key to display the following CAL VOFFSET 3 Press ENTER The instrument will prompt for a short INPUT SHORT 4 Connect a triax short to the rear panel INPUT jack Use the supplied Model 237 ALG 2 triax cable or equivalent with red and black alligator clips connected together 5 Press ENTER to complete offset voltage calibration 6 Press EXIT to return to normal display 2 18 Measurement Concepts SCPI programming Table 2 5 lists SCPI commands used for input bias current and offset voltage calibration Table 2 5 SCPI commands input bias current and offset voltage calibration Commands Description CALibration UNPRotected IOFFset Input bias current calibration CALibration UNPRotected VOFFset Offset voltage calibration SCPI command input bias current calibration 1 Connect a triax shielding cap to the rear panel INPUT jack Use a Keithley CAP 31 or equivalent 2 Send the following command to perform input bias current calibration CAL UNPR IOFF 3 Allow the Model 6514 to complete the calibration process SCPI command offset voltage calibration 1 Connect a triax short to the rear panel INPUT jack Use the supplied Model 237 ALG 2 triax cable or equivalent with red and black alligator clips connected together 2 Send the following command to perfor
314. setting upper and or lower autorange limits For example if you know the maximum input will be around 1uA you can set the upper current range limit to 2uA This eliminates the 20uA 200HA 2mA and 20mA ranges from the search therefore increasing the range change speed Should the input exceed 2 1uA the OVER FLOW message will be displayed Perform the following steps to set upper and or lower autorange limits 1 Select the V I or Q function Press SHIFT and then one of the following RANGE keys a Press the RANGE a key to display the present UPPER range limit b Press the RANGE y key to display the present LOWER range limit Use the RANGE 4 and y keys to display the desired limit 4 Press ENTER p NOTE Ifyou attempt to select an incompatible range limit it will be ignored and TOO LARGE or TOO SMALL will be displayed briefly For example if the lower range limit is 20V trying to set the upper limit to 2V will result in the TOO SMALL error Autorange groups for Q To optimize range change speed for charge measurements the instrument will only autorange between two ranges With the high range group selected the instrument can only autorange between the 2uC and 20uC ranges With the low range group selected the instrument can only autorange between the 20nC and 200nC ranges If the HIGH range group is presently selected and the instrument is on the 20nC or 200nC range autorange disabled pressing the A
315. sourced test voltage I is the measured current Figure 4 9 C tions surfac PC Board ne tons Sul ace Test Pattern insulation resistance l test lz 6514 230 Picommeter V Source Equivalent Circuit Coulombs M easurements Measurement overview Summarizes the charge measurement capabilities of the Model 6514 Auto discharge Explains how to use the auto discharge feature of Model 6514 C oulombs measurement procedure Provides the procedure to measure coulombs SCPI programming Covers the basic SCPI commands used for the coulombs function Amps measurement considerations Covers measurement considerations that apply to coulombs measurements Application Summarizes an application to measure capacitance 5 2 Coulombs Measurements Measurement overview Coulombs measurements Model 6514 can make coulombs measurements from 10fC to 2 1uC using four measurement ranges 20nC 200nC 2uC and 20uC In the coulombs function an accurately known capacitor is placed in the feedback loop of the amplifier so that the voltage developed is proportional to the integral of the input current in accordance with the following formula lo Q V fidt se Where V is the voltage C is the known capacitance Q is the charge The voltage is scaled and displayed as charge External feedback The external feedback mode of Model 6514 can be used to measure non standard cha
316. ss ENTER to complete offset voltage calibration The unit will display the following message CALIBRATING Input bias current calibration 1 Turn on the power and allow a one hour warm up period before calibrating input bias current or offset voltage 2 Restore factory defaults as outlined above 3 Press SHIFT then CAL and note that the unit displays the following CAL RUN 4 Use the down RANGE key to display the following CAL IOFFSET 5 Press ENTER The instrument will prompt for an open input INPUT CAP 18 10 Performance Verification 6 Connect the triax shielding cap to the rear panel INPUT jack 7 Press ENTER to complete input bias current calibration The unit will display the fol lowing message CALIBRATING Volts measurement accuracy Figure 18 1 Connections for volts verification Follow the steps below to verify that Model 6514 volts function measurement accuracy is within specified limits The test involves applying accurate DC voltages and then verifying that Model 6514 voltage readings are within required limits WARNING Hazardous voltages are used in the following procedures Always place the calibrator in standby before changing test connections 1 With the power off connect the voltage calibrator to Model 6514 INPUT jack as shown in Figure 18 1 Use the appropriate triax to BNC low noise coaxial cable and BNC to dual banana plug adapters where shown Low noise Coax BNC Cable
317. ss the self test options Use the up or down RANGE key to display TEST DISP Press ENTER to start the test There are four parts to the display test Each ttme ENTER is pressed the next part of the test sequence is selected The four parts of the test sequence are as follows e All annunciators are displayed e The segments of each digit are sequentially displayed e The 12 digits and annunciators are sequentially displayed e The annunciators located at either end of the display are sequentially displayed When finished abort the display test by pressing EXIT The instrument returns to normal operation The KEY test allows you to check the functionality of each front panel key Perform the fol lowing steps to run the KEY test 1 Press SHIFT and then TEST to access the self test options Use the up or down RANGE key to display TEST KEY Press ENTER to start the test When a key is pressed the label name for that key is dis played to indicate that it is functioning properly When the key is released the message NO KEY PRESS is displayed Pressing EXIT tests the EXIT key However the second consecutive press of EXIT aborts the test and returns the instrument to normal operation Specifications A 2 Specifications VOLTS ACCURACY TEMPERATURE 1 Year COEFFICIENT 5 DIGIT 18 28 C 0 18 C amp 28 50 C RANGE RESOLUTION rdg counts Y rdg counts C 2V 10 pV 0 025 4 0 003 2 20V 100 pV 0 025 3 0 0
318. ssage Always use the short form versions of commands and parameters Minimize the amount of white space in command strings Keep numeric parameters simple i e 1 vs 1 000e 00 OS eto Use all upper case 12 16 Remote O peration Response messages A response message is the message sent by the instrument to the computer in response to a query command program message Sending a response message After sending a query command the response message is placed in the output queue When Model 6514 is addressed to talk the response message is sent from the output queue to the com puter Multiple response messages If you send more than one query command in the same program message see Multiple Command Messages the multiple response messages for all the queries is sent to the computer when Model 6514 is addressed to talk The responses are sent in the order that the query com mands were sent and are separated by semicolons Items within the same query are separated by commas The following example shows the response message for a program message that contains four single item query commands 0 1 1 0 Response Message Terminator RMT Each response is terminated with an LF line feed and EOI end or identify The following example shows how a multiple response message is terminated 0 1 1 0 lt RMT gt Message exchange protocol Two rules summarize the message exchange protocol Rule 1 A
319. ssing the LIMIT key When using a component handler the testing process will stop after the last DUT is tested 10 12 Limit Tests SCPI programming Table 10 2 SCPI commands limit tests Command Description Default Ref CALCulate2 CALCulate2 Subsystem FEED lt name gt Select input path for limit testing CALCulate 1 SENS A or SENSe 1 LIMit 1 Limit 1 Testing UPPer Configure upper limit DATA lt n gt Set limit 9 99999e20 to 9 99999e20 1 0 SOURce2 lt NDN gt or lt NRf gt Specify 4 bit output fail pattern 15 B LOWer Configure lower limit DATA lt n gt Set limit 9 99999e20 to 9 99999e20 1 0 SOURce2 lt NDN gt or lt NRf gt Specify 4 bit output fail pattern 15 B STATe lt b gt Enable or disable Limit 1 test OFF FAIL Return result of Limit 1 test 0 pass or 1 fail Cc LIMit2 Limit 2 Testing UPPer Configure upper limit DATA lt n gt Set limit 9 99999e20 to 9 99999e20 1 0 SOURce2 lt NDN gt or lt NRf gt Specify 4 bit output fail pattern 15 B LOWer Configure lower limit DATA lt n gt Set limit 9 99999e20 to 9 99999e20 1 0 SOURce2 lt NDN gt or lt NRf gt Specify 4 bit output fail pattern 15 STATe lt b gt Enable or disable Limit 2 test OFF FAIL Return result of Limit 2 test 0 pass or 1 fail C CLIMits Composite Limits CLEar Clear I O port and restore it back to SOURce2 TTL settings IMMediate Clears I O port immediat
320. st Result OK Pass Pass L1 Fail Not Performed L2 Pass Fail 10 4 Limit Tests Binning Figure 10 4 Binning system NOTES Display messages indicate which test or tests have failed but they do not indicate which limit HI or LO has failed When using remote operation you can determine which limit failed by reading the measurement event register See Ref B for the FAIL commands in Table 10 2 Relative Rel mX b and percent can be used with limit testing The tests will be done on the result of the math operation not the input values These math operations are covered in Section 7 Application A typical application for a 2 stage limit test is to sort a batch of DUT accord ing to tolerance For example you may want to sort resistors all having the same nominal value into three groups 1 5 and gt 5 The limits for limit 1 would be the 5 tolerances and the limits for limit 2 would be the 1 tolerances If a resistor passes both tests it belongs in the 1 group If it passes limit 1 but fails limit 2 it belongs in the 5 group If it fails both tests it belongs in the gt 5 group Even though no additional equipment is required to perform limit tests on the DUT Model 6514 can be used with a component handler to perform binning operations Based on the out come of a test the component handler will place the DUT in the assigned bin Figure 10 4 shows a basic binning system After all programmed testing on t
321. ster can be read by the users test program to determine if a service request SRQ has occurred and what event caused it Status byte and SR Q The status byte register receives the summary bits of four status reg ister sets and two queues The register sets and queues monitor the various instrument events When an enabled event occurs it sets a summary bit in the status byte register When a summary bit of the status byte is set and its corresponding enable bit is set as programmed by the user the RQS MSS bit will set to indicate that an SRQ has occurred Status register sets A typical status register set is made up of a condition register an event register and an event enable register A condition register is a read only register that constantly updates to reflect the present operating conditions of the instrument When an event occurs the appropriate event register bit sets to 1 The bit remains latched to 1 until the register is reset When an event register bit is set and its corresponding enable bit is set as programmed by the user the output summary of the register will set to 1 which in turn sets the summary bit of the status byte register Queues Model 6514 uses an output queue and an error queue The response messages to query commands are placed in the output queue As various programming errors and status mes sages occur they are placed in the error queue When a queue contains data it sets the appropri ate sum
322. sure best accuracy and resolution Autoranging When using autorange the instrument automatically goes to the most sensitive available range to measure the applied signal Up ranging occurs at 105 of range while down ranging occurs at the range value For example if on the 20V range the instrument will go up to the 200V range when the input signal exceeds 21V While on the 200V range the instrument will go down to the 20V range when the input level goes to 20V The AUTO key toggles the instrument between manual ranging and autoranging The AUTO annunciator turns on when autoranging is selected To disable autoranging press AUTO or the RANGE a or y key Pressing AUTO to disable autoranging leaves the instrument on the present range Range Units Digits Rate and Filters 6 3 Every time an autorange occurs a search for every available range of the selected function is performed The time it takes to perform the search could slow down range change speed signif icantly For V I and measurements upper and or lower autorange limits can be set to reduce search time For Q measurements the instrument will only autorange between the two higher charge ranges high range group or between the two lower charge ranges low range group NOTE Range limits and groups are not in effect for manual ranging Every range is accessi ble with manual range selection Autorange limits for V and Q Search time for V I and Q can be reduced by
323. surements 00 2 8 General purpose test fixture 0 le eeeeeeeecsecneeseeseceeeeeeeesaeees 2 9 Capacitor test circuit without protection oer 2 11 Capacitor test circuit with protection 20 0 0 ee eeeeeeeeeees 2 11 Floating measurements 0 0 eee eee cee ceee cee ceseeeeeeeeeeeeesetees 2 12 Equivalent input impedance with zero check enabled 2 14 Volts and O hms Measurements High impedance voltage measurement 0 0 0 0 eect eres 3 3 Connections for unguarded volts and ohms eee 3 5 Connections for guarded volts and ohms eee eee 3 6 Meter loading sciccsct deci diesctist Sean ahittenieiineneviensaevidess 3 9 Effects of input capacitance oo eee eee eeeeeeeeeeeeeeeeeeeeeees 3 11 Settling UME irrien En nea E EE EE AEE 3 12 Unguarded input cable eee ceeeeeceeeeseeeeeeeeeeeeeseeees 3 12 Guarded input Cable c cccccsscescesssstenssssseessneuscuenesssversebnetes 3 13 Measuring dielectric absorption 00 0 0 ee eeeeeeeeeeeeeeeeeees 3 15 Amps Measurements Connections for AMPS eee cee eee ceeeeeeceseeeeecneeesecseeaeenaes 4 4 High impedance current measurements 00 0 0 eee eee eee eeeee 4 5 Floating current measurements 0 0 00 ee eeeeeeeeeeneeceeeeeneeeneeeee 4 7 Voltage burden considerations 20 0 0 eee ee eseeeeceeeeeneeeees 4 10 Source resistance and capacitance 0 cece eeeeeeceeeeees 4 11 Connections diode leakage current test eeceeeeeeteeeeees 4 13 Connections capacitor lea
324. t circuitry A typical test circuit to measure the leakage current of a capacitor is shown in Figure 2 7 When Switch S is closed an initial charging current will flow and the high voltage will be seen across the input of Model 6514 Figure 2 7 eae Capacitor test circuit S without protection Capacitor Under Test y 6514 a Ammeter Adding a resistor and two diodes 1N3595 as shown in Figure 2 8 will provide considerable extra protection The resistor must be large enough to limit the current through the diodes to 10mA or less and be large enough to withstand the supply voltage The protection circuit should be enclosed in a light tight conductive shield Figure 2 8 Protection Circuit o P AVAVAVE e HOGAR Vel Capacitor R HI protection U nder Test soti v D1 gt D2 ous LO rs WY Floating measurements With the ground link between the COMMON and CHASSIS banana jack terminals removed Model 6514 can perform floating measurements up to 500V above chassis ground These mea surements can result in safety concerns 2 12 Measurement Concepts Figure 2 9 shows two examples where Model 6514 floats at a hazardous voltage level In Fig ure 2 9A a shock hazard 100V exists between meter input LO and chassis ground If meter input LO is connected to a noise shield then the shock hazard will also be present on that shield In Figure 2 9B a shock hazard 200V exists between the me
325. te ULIMit lt n gt Specify upper range limit for autorange 0 to 2 1e11 Q 200GQ LLIMit lt n gt Specify lower range limit for autorange 0 to 2 1e11 Q 2kQ CHARge Measure charge RANGe Range selection UPPer lt n gt Specify expected reading 21e 6 to 21e 6 C 200nC AUTO lt b gt Enable or disable autorange see Note LGRoup lt name gt Select autorange group HIGH or LOW HIGH For Digits DISPlay DIGITs lt n gt DISPlay Subsystem Set display resolution 4 to 7 where 4 3 digit resolution 4 2 digit resolution 5 2 digit resolution 6 2 digit resolution 5 6 7 Note Rational numbers can be used For example to set 4 resolution send a value of 4 5 the 6514 rounds it to 5 Note RST default is ON and SYSTem PRESet default is OFF Programming example range and digits The following command sequence selects the 200V range and sets display resolution to 3 RST VOLT RANG 200 DISP DIG 3 5 Restore RST defaults Set V function to 200V range Set display resolution to 3 digits 6 6 Range U nits Digits Rate and Filters Rate The RATE key selects the integration time of the A D converter This is the period of time the input signal is measured The integration time affects the amount of reading noise as well as the ultimate reading rate of the instrument The integration time is specified in parameters based on a number of power line cycles NPLC wher
326. te the buffer is enabled see Section 8 for details on buffer operation To start the test press STEP on the switching mainframe to take it out of idle and start the scan The switching mainframes output pulse triggers Model 6514 to take a reading and store it Model 6514 then sends an output trigger pulse to the switching mainframe to close the next channel This process continues until all 10 channels are scanned measured and stored Details of this testing process are explained in the following paragraphs and are referenced to the operation model shown in Figure 9 9 9 14 Triggering Figure 9 9 Operation model for triggering example e and f 7001or 7002 Press STEP to start scan 6514 C dle _ C idle Bypass Wait for f Trigger Link Wait for Trigger z747 Trigger Link Trigger Scan Make Channel Measurement Output Tigger Trigger Output Trigger Trigger Scanned 10 Channels 10 Measurements No Operation of Model 6514 starts at point A in the flowchart where it waits for an external trigger Pressing STEP takes Model 7001 2 out of idle and places operation at point B in the flowchart For the first pass through Model the scanner does not wait at point B Instead it closes the first channel point C After the relay settles Model 700
327. ter input HI and LO and chas sis ground If meter LO is connected to a shield then the shock hazard will also be present on that shield Figure 2 9 2 HI Floating measurements 6514 Ry Voltmeter a LO 200V Ry Rp Ry 100V A Voltage measurement LO 200V R3 HI T ir 6514 Ry Ammeter A R 200V y agi B Current measurement WARNING WARNING CAUTION The maximum voltage common mode between electrometer LO and chas sis ground is 500V Exceeding this value may create a shock hazard When floating input LO above 30V from earth chassis ground hazardous voltage will be present at the analog outputs PREAMP OUT and 2V ANALOG OUTPUT Hazardous voltage may also be present when the input voltage exceeds 30V in the Volts function Connecting PREAMP OUT COMMON or 2V ANALOG OUTPUT to earth chassis ground while floating the input may damage the instrument M easurement Concepts 2 13 Zero check and zero correct Table 2 3 lists the display messages associated with zero check and zero correct The two character message is displayed along with the reading Table 2 3 Display messages for zero check and zero correct Display Message Zero Check Zero Correct ZC On Off ZZ On On CZ Off On Zero check When zero check is enabled on the input amplifier is reconfigured to shunt the input signal to low as shown in Figure 2 10 With zero check enabled it will remain
328. ternal sources i e radio and TV transmitters can affect sensitive measurements Volts and O hms Measurements Measurement overview Summarizes the volts and ohms measurement capabilities of Model 6514 Guarding Explains guarding and the benefits derived from it for high impedance volts and ohms measurements Volts and ohms measurement procedure Provides the procedure to measure volts and ohms SCPI programming Covers the basic SCPI command used for the volts and ohms functions Volts and ohms measurement considerations Covers measurement considerations that apply to volts and ohms measurements Application Shows how to measure dielectric absorption of a capacitor 3 2 Volts and Ohms Measurements Measurement overview Volts measurements Model 6514 can make volts measurements from 10uV to 210V using three measurement ranges 2V 20V and 200V Ohms measurements Model 6514 makes ohms measurements by sourcing a test current and measuring the voltage drop across the DUT The resistance reading is then calculated R V 1 and displayed The electrometer can make ohms measurements from 10mQ to 210GQ using nine measurement ranges 2kQ 20kQ 200kQ 2MQ 20MQ 200M9 2G 20GQ and 200GQ NOTE Accuracy specifications for all measurement functions are provided in Appendix A Guarding The purpose of guarding is to eliminate the effects of leakage resistance and capacitance that can exist b
329. the appropriate range When you query the range with RANGe the instrument sends back the full scale value of its present range Note that the Model 6514 rounds the range parameter to an integer before choosing the appro priate range Sending VOLTage RANGe 21 6 will set the Volts function to the 200V range The parameter 21 6 is rounded to 22 which exceeds the 20V range The following program demonstrates range and function changes A measurement will be taken while on the Amps and Ohms function For QuickBASIC 4 5 and CEC PC488 interface card edit the follow ing line where the QuickBASIC libraries are on your computer SINCLUDE c qb45 ieeeqb bi Initialize the CEC interface as address 21 CALL initialize 21 0 Restore RST defaults CALL SEND 14 rst status Set Amps for 20uA range and Ohms for 2MW range CALL SEND 14 curr rang 20e 6 status CALL SEND 14 res rang 2e6 status Switch to Amps function and take reading Each READ will trigger one reading CALL SEND 14 func curr status CALL SEND 14 read status reading S SPACES 80 CALL ENTER reading length 14 status PRINT reading Switch to Ohms function and take reading CALL SEND 14 func res status CALL SEND 14 read status reading S SPACES 80 CALL TER
330. the bit pattern and places the DUT in the appropriate bin Model 6514 can be used with either of the two basic types of handlers When used with a cat egory pulse handler Model 6514 pulses one of the four handler lines The handler then places the DUT into the bin assigned to the pulsed line When used with a category register handler Model 6514 outputs a bit pattern to three handler lines After Model 6514 sends the end of test EOT strobe pulse to the fourth handler line the handler places the DUT into the bin assigned to that bit pattern Component handler types Model 6514 can accommodate two different types of component handlers category pulse and category register Category pulse component handler When using this type of handler Model 6514 pulses one of the four handler lines when a pass or fail condition occurs The handler then places the DUT in the bin assigned to that pulsed line When interfacing to this type of handler a maximum of four component handler bins are sup ported If the handler requires low going pulses then the four digital output lines of Model 6514 must be initially set to high This initial HI HI HI HI clear pattern on the output lines represents a no action condition for the handler since it is waiting for one of the lines to go low A line goes low when the defined fail or pass pattern sets it low For example if you want a particular test failure to pulse line 4 of the handler the defined f
331. the desired memory location 0 USRO 1 USRI 2 USR2 4 Press ENTER Restoring a setup Perform the following steps to restore a setup 1 Press SHIFT and then SETUP to display the restore menu 2 Use the a or v key to display the desired setup FACT GPIB USRO USR1 or USR2 3 Press ENTER Remote operation Getting Started 1 13 Saving and restoring user setups The SAV and RCL commands are used to save and recall user setups These commands are documented in Section 14 Restoring factory or GPIB default setups The SYSTem PRESet command returns Model 6514 to the factory defaults and the RST command returns it to the GPIB defaults The RST command is documented in Section 14 and SYSTem PRESet is covered in Section 16 SYSTem Subsystem Selecting power on setup The SYSTem POSetup command is used to select which setup to return to on power up The SYSTem POSetup command is documented in Section 16 SYSTem Subsystem Table 1 2 Default settings Setting Factory GPIB Arm Layer CONF ARM Arm In Source Event IMM IMM Arm Count INF 1 Input Trigger Link Line 1 1 Source Bypass NEVER NEVER Output Trigger Link Line 2 2 Output Trigger Off Off Auto Discharge Off Off Level 2e 6 2e 6 Buffer STORE Disabled Disabled Count No effect No effect Digital Filter AVG Off Off Count 10 10 Type Moving Moving Display Resolution DIGIT 5 2 digits 5 2 digits Function Volts Volts Guard Off Off GPI
332. the slowest active device on the bus One of the three handshake lines is controlled by the source the talker sending information while the remaining two lines are controlled by accepting devices the listener or listeners receiving the information The three handshake lines are DAV DATA VALID The source controls the state of the DAV line to indicate to any lis tening devices whether or not data bus information is valid NREFD Not Ready For Data The acceptor controls the state of NRFD It is used to signal to the transmitting device to hold off the byte transfer sequence until the accepting device is ready NDAC Not Data Accepted NDAC is also controlled by the accepting device The state of NDAC tells the source whether or not the device has accepted the data byte The complete handshake sequence for one data byte is shown in Figure F 2 Once data is placed on the data lines the source checks to see that NRFD is high indicating that all active devices are ready At the same time NDAC should be low from the previous byte transfer If these conditions are not met the source must wait until NDAC and NRFD have the correct sta tus If the source is a controller NRFD and NDAC must be stable for at least 100ns after ATN is set true Because of the possibility of a bus hang up many controllers have time out routines that display messages in case the transfer sequence stops for any reason Once all NDAC and NRFD are properly
333. tion e Model 6514 Instruction Manual P N 6514 901 01 e Manual Addenda pertains to any improvements or changes concerning the instrument or manual If an additional manual is required order the appropriate manual package The manual pack ages include a manual and any pertinent addenda Getting Started 1 3 Options and accessories Input cables connectors and adapters Model 237 A LG 2 This is a 6 6 ft 2 meter low noise triax cable terminated with a 3 slot male triax connector on one end and 3 alligator clips on the other One Model 237 ALG 2 is included Model 237 BNC TRX adapter This is a male BNC to 3 lug female triax connector guard disconnected It is used to terminate a triax cable with a BNC plug M odel 237 T RX T adapter This is a 3 slot male to dual 3 lug female triax tee adapter for use with 7078 TRX triax cables Model 237 TRX TBC connector This is a 3 lug female triax bulkhead internal mount connector with cap for assembly of custom test fixtures and interface connections Model 7078 TR X TBC connector This is a 3 lug female triax bulkhead external mount connector with cap for assembly of custom test fixtures and interface connections M odel 7078 T R X 3 7078 T R X 10 and Models 7078 T R X 20 triax cables These are low noise triax cables terminated at both ends with 3 slot male triax connectors The 3 model is 3 ft 0 9m in length the 10 model is 10 ft 3m in length
334. tion for the arm layer is satis fied immediately allowing operation to continue on into the trigger layer GPIB ARM SOURce BUS Event detection for the arm layer is satisfied when a bus trigger GET or TRG is received by Model 6514 Timer ARM SOURce TIMer Event detection for the arm layer is immediately sat isfied after the instrument leaves the idle state Detection for each subsequent pass is sat isfied when the programmed timer interval elapses The timer resets to its initial state when the instrument goes back into idle Manual ARM SOURce MANual Event detection for the arm layer is satisfied by pressing the TRIG key Model 6514 must be in the local mode for it to respond to the TRIG key Press LOCAL or send LOCAL 14 over the bus to place Model 6514 in local TLink ARM SOURce TLINk Event detection for the arm layer is satisfied when an input trigger via the TRIGGER LINK connector is received by Model 6514 Note that if the source bypass is set to ONCE ARM DIRection SOURCce operation will initially loop around the source detector after the instrument leaves the idle state Detection for each subsequent pass is satisfied by an input trigger The bypass resets when the instru ment goes into idle STest ARM SOURce NSTest Event detection for the arm layer is satisfied when a negative going pulse via the SOT line of the Digital I O is received from a component handle see Limit Testing in Section 10 Test
335. transfer data using seven or eight data bits and one stop bit Parity Parity for the RS 232 interface can be set to none even or odd Terminator Model 6514 can be configured to terminate each program message that it transmits to the con troller with any of the following combinations of lt CR gt and lt LF gt e LF line feed e CR carriage return e LFCR line feed carriage return e CRLF carriage return line feed 12 18 Figure 12 4 Remote O peration Flow control signal handshaking Signal handshaking between the controller and the instrument allows the two devices to com municate to each other regarding being ready or not ready to receive data Model 6514 does not support hardware handshaking flow control Software flow control is in the form of X_ON and X_OFF characters and is enabled when XonXoFF is selected from the RS232 FLOW menu When the input queue of Model 6514 becomes more than 3 4 full the instrument issues an X_OFF command The control program should respond to this and stop sending characters until Model 6514 issues the X_ON which it will do once its input buffer has dropped below half full Model 6514 recognizes X_ON and X_OFF sent from the controller An X_OFF will cause Model 6514 to stop outputting characters until it sees an X_ON Incoming commands are processed after the lt CR gt character is received from the controller If NONE is the selected flow control then there will be no signal handshaki
336. trometer input in the external feedback mode is shown in Fig ure 11 7 An input current applied to the inverting input of the op amp is nulled by a current feedback through the internal feedback network made up of Rpg and Cpp Because the output of the op amp appears at the preamp out this internal network can be replaced by an external net work connected between the preamp output and input HI connections When using external feedback the following factors must be taken into account 1 The maximum current value that can be supplied by the preamp output is 20mA in amps and ohms 1mA in volts The maximum voltage span in external feedback is 20V The input impedance in the external feedback mode is given by the relationship Zn Zrp Ay where Zpp is the impedance of the external feedback network and Ay is the open loop gain of the electrometer typically greater than 55x106 Note that the input impedance is Zy LOMQ II Z g when zero check is enabled The voltage at the preamp out terminal is given by the formula V IZFB Any feedback elements should be housed in a suitable shielded enclosure see Shielded Fixture Construction below Insulators connected to input HI should be made of Teflon or other high quality insulating material and should be thoroughly cleaned to maintain the high input impedance and low input current of Model 6514 If these insulators become contaminated they can be cleaned with methanol and then with cl
337. ts to this trigger if BUS is the programmed arm control source The control source is programmed from the TRIGger subsystem NOTE Details on triggering are covered in Section 9 Programming example The following command sequence configures Model 6514 to be controlled by bus triggers The last line which sends a bus trigger triggers one measurement Each subsequent bus trigger will also trigger a single measurement RST ARM SOUR BUS ARM COUN INF Restore RST defaults Select BUS control source Set arm layer count to infinite 4 4 4 ww INIT Take 6514 out of idle TRG Trigger one measurement F TST self test query Run self test and read result Use this query command to perform a checksum test on ROM The command places the coded result 0 or 1 in the output queue When Model 6514 is addressed to talk the coded result is sent from the output queue to the computer A returned value of zero 0 indicates that the test passed and a value of one 1 indicates that the test failed G WAI wait to continue Wait until previous commands are completed Effectively the WAI command is a No Op no operation for Model 6514 and thus does not need to be used Two types of device commands exist e Sequential commands A command whose operations are allowed to finish before the next command is executed e Overlapped commands A command that allows the execution of subsequent com mands while device operations
338. ture of Model 6514 when it was last calibrated SCPI programming zero check and zero correct Table 2 4 SCPI commands zero check and zero correct Commands Description Default Ref SYSTem SYSTem Subsystem ZCHeck lt b gt Enable or disable zero check ON ZCORrect Zero correct STATe lt b gt Enable or disable zero correct OFF A ACQuire Acquire a new zero correct value B INITiate Trigger a reading B A SYSTem ZCORrect STATe lt b gt This method to perform zero correction is consistent with the way it is performed from the front panel That is zero correction is performed while zero check is enabled SYST ZCH ON Enable zero check SYST ZCOR ON Perform zero correction A second method to perform zero correction is to first acquire the zero correct value see Ref B 2 16 Measurement Concepts B SYSTem ZCO RrectACQ uire The zero correct value can only be acquired while zero check is enabled The internal offset will become the correction value Zero correction can then be performed with zero check dis abled This acquire method makes it convenient if you need to re zero the selected function often The following command sequence uses the acquire method to zero correct the 2V range SYST FUNC VOLT INIT SYST SYST SYST ZCH ON N VOLT RANG 2 i ZCOR ACQ i ZCH OFF ZCOR ON X Enable zero check Select Volts function Select 2V range
339. ual standard resistor value For example assume you are calibrating the 20pA range using an actual 100 5GQ standard resistor value The actual calibrator voltage is 20pA x 100 5GQ 2 01V Charge calculations Calibrator voltages for verification charge values are calculated as follows V Q C Where V required calibrator voltage Q verification current C actual standard resistor value For example the required calibrator voltage for a 200nC range verification charge value with a 99 5nF standard capacitance value is 200nC 99 5nF 2 01005V 18 8 Performance Verification Performing the verification test procedures Test summary Volts measurement accuracy Amps measurement accuracy Ohms measurement accuracy Coulombs measurement accuracy If Model 6514 is not within specifications and not under warranty see the calibration proce dures in Section 19 for information on calibrating the unit Test considerations When performing the verification procedures Restore Model 6514 factory front panel defaults and perform input bias current and volt age offset calibration as outlined below Make sure that the test equipment is properly warmed up and properly connected to Model 6514 INPUT jack Be sure test equipment is set up for the proper function and range Allow the input signal to settle before making a measurement Do not connect test equipment to Model 6514 through a scanner multiplexer or other switching equipment
340. ubsystem MEDian Median Filter RANK lt n gt Specify filter rank 1 to 5 1 STATe lt b gt Enable or disable median filter OFF For digital filter SENSe 1 SENSe Subsystem AVERage Digital Filter TCONtrol lt name gt Select filter control MOVing or REPeat REP COUNt lt n gt Specify filter count 1 to 100 10 STATe lt b gt Enable or disable digital filter OFF Range Units Digits Rate and Filters 6 11 Programming example The following command sequence configures and enables both filters Median Filter D RANK 5 Set rank to 5 D ON Enable median filter EI Digital Filter AVER COUN 20 Set filter count to 20 AVER TCON MOV Select moving filter AVER ON Enable digital filter Relative mX and Percent e Relative Explains how to null an offset or establish a baseline value Includes the SCPI commands for remote operation e mX b and percent Covers these two basic math operations and includes the SCPI commands for remote operation 7 2 Relative mX b and Percent Relative Relative Rel nulls an offset or subtracts a baseline reading from present and future readings When a Rel value is established subsequent readings will be the difference between the actual input and the Rel value Displayed Rel ed Reading Actual Input Rel Value A Rel value is the same for all measurement ranges For example a Rel value
341. ue Remote O peration 12 13 Case sensitivity Common commands and SCPI commands are not case sensitive You can use upper or lower case and any case combination Examples RST rst DATA data SYSTem PRESet system preset Long form and short form versions A SCPI command word can be sent in its long form or short form version The command tables in this manual use the long form version However the short form version is indicated by upper case characters SYSTem PRESet long form SYST PRES short form SYSTem PRES long form and short form combination Note that each command word must be in either long form or short form For example SYSTe PRESe is illegal and will generate an error The command will not be executed Short form rules Use the following rules to determine the short form version of any SCPI command e If the length of the command word is four letters or less no short form version exists sauto auto These rules apply to command words that exceed four letters e Ifthe fourth letter of the command word is a vowel delete it and all the letters after it immediate imm e If the fourth letter of the command word is a consonant retain it but drop all the letters after it format form e If the command contains a question mark or a non optional number included in the command word you must include it in the short form version delay del e Command words or characters that are enclo
342. ures Model 6514 to perform measurements using the external feedback mode Enable zero check Enabl xternal feedback Select Volts function Disable zero check Trigger measurement s and request reading s SYST ZCH ON VOLT XFE ON FUNC VOLT SYST ZCH OFF READ 4 4 4 ww 12 Remote O peration Selecting and configuring an interface Explains how to select and configure an interface GPIB or RS 232 GPIB operation and reference Covers the following GPIB topics GPIB Bus Standards GPIB Bus Connections Primary Address Selection General Bus Commands Front Panel GPIB Operation Programming Syntax R S 232 interface reference Provides basic reference information for the RS 232 interface and explains how to make connections to the computer 12 2 Remote O peration Selecting and configuring an interface Interfaces Model 6514 supports two built in remote interfaces e GPIB interface e RS 232 interface You can use only one interface at a time At the factory the GPIB bus is selected You can select the interface only from the front panel The interface selection is stored in non volatile memory it does not change when power has been off or after a remote interface reset GPIB interface The GPIB is the IEEE 488 interface Model 6514 must be assigned to unique address At the factory the address is set to 14 but can be set to any value from 0 to 30 However the addres
343. ures in this section to calibrate Model 6514 These procedures require accurate test equipment to source precise DC voltages currents resistances and charge values WARNING _ Theinformation in this section is intended only for qualified service person nel Do not attempt these procedures unless you are qualified to do so These procedures may expose you to hazardous voltages which could cause severe injury or death Environmental conditions Temperature and relative humidity Conduct the calibration procedures at an ambient temperature of 18 28 C 65 82 F with rel ative humidity of less than 70 unless otherwise noted Warm up period Allow Model 6514 to warm up for at least one hour before performing calibration If the instrument has been subjected to temperature extremes those outside the ranges stated above allow additional time for the instrument s internal temperature to stabilize Typically allow one extra hour to stabilize a unit that is 10 C 18 F outside the specified temperature range Also allow the test equipment to warm up for the minimum time specified by the manufacturer Line power Model 6514 requires a line voltage of 100 120 VAC or 220 240 VAC at a line frequency of 50 or 60Hz The instrument must be calibrated while operating from a line voltage within this range Calibration 19 3 Calibration considerations When performing the calibration procedures e Make sure that the test equipment is
344. utomatic calculations As an alternative to manual calculations you can use a computer to read the standard values from Model 5156 via remote programming commands and then have the computer perform the calculations See Appendix H for details Note that you can use the OPT command Section 14 to determine if the Model 5156 is properly connected Calibration 19 7 Calibration procedure The calibration procedure should be performed in the following order e Preparing for calibration e Offset voltage and input bias current calibration e Volts calibration e Amps calibration e Coulombs calibration e Ohms calibration e Entering calibration dates and saving calibration e Locking out calibration NOTE Ohms calibration must be done last to allow charge to bleed off internal insulators Preparing for calibration 1 Turn on Model 6514 and the calibrator and allow them to warm up for at least one hour before performing calibration 2 Press SHIFT then CAL The instrument will display the following CAL RUN 3 Use the up or down RANGE key to display the following CAL UNLOCK 4 Press ENTER The instrument will prompt for the calibration code CODE 5 Enter the current calibration code on the display Factory default 006514 Use the up and down RANGE keys to select the letter or number and use the left and right arrow keys to choose the position Press ENTER to complete the process and the unit will display NEW CODE
345. ve been executed OPC Operation complete query Places an ASCII 1 into the output queue when all B pending selected device operations have been completed OPT Option query The value 5156 is returned if the Model 5156 calibration source is connected to the Model 6514 The value 0 is returned if the Model 5156 is not connected RCL lt NRf gt Recall command Returns Model 6514 to the user saved setup C RST Reset command Returns Model 6514 to the RST default D conditions SAV lt NRf gt Save command Saves the present setup as the user saved setup e SRE lt NRf gt Service request enable command Programs the service request enable register Sec 13 SRE Service request enable query Reads the service request enable register Sec 13 STB Status byte query Reads the status byte register Sec 13 TRG Trigger command Sends a bus trigger to Model 6514 E TST Self test query Performs a checksum test on ROM and returns the F result WAI Wait to continue command Wait until all previous commands are executed G A IDN identification query Reads identification code The identification code includes the manufacturer model number serial number and firm ware revision levels and is sent in the following format KEITHLEY INSTRUMENTS INC MODEL 6514 xxxxxxx yyyyy zzzzz w Where XXXXXXX is the serial number yyyyy zzzzz is the firmware revision levels of the digital board ROM and display board ROM Note t
346. wn 240 setting is for line voltages of 220 240VAC The pro cedure to change the line voltage setting is provided in Section 20 CAUTION Operating theinstrument on an incorrect line voltage may cause damage to the instrument possibly voiding the warranty 2 Before plugging in the power cord make sure the front panel power switch is in the off O position 3 Connect the female end of the supplied power cord to the AC receptacle on the rear panel Connect the other end of the power cord to a grounded AC outlet WARNING Thepower cord supplied with Model 6514 contains a separate ground wire for use with grounded outlets When proper connections are made instru ment chassis is connected to power line ground through the ground wire in the power cord Failure to use a grounded outlet may result in personal injury or death due to electric shock 4 Turn on the instrument by pressing the front panel power switch to the on 1 position Line frequency selection During the power up sequence the selected line frequency setting is displayed The line fre quency setting can be changed from the front panel by holding in the TRIG key during the power up sequence This action toggles between 50 and 60Hz The command to remotely set line frequency is listed in Table 1 1 SCPI programming Table 1 1 SCPI commands line frequency Command Description SYSTem SYSTem Subsystem LFRequency lt freq gt Select power line frequency in Hz 50 or
347. y to display the desired rank 1 to 5 and press ENTER Digital filter Figure 6 2 Digital filter types moving and repeating Conversion 10 e 6 e 4 e 3 Conversion 1 gt Reading 10 Conversion Conversion Range Units Digits Rate and Filters 6 9 11 10 9 8 1 6 5 4 3 2 gt Reading 11 A Class Average Readings 10 Type Moving Conversion 10 9 8 7 e 6 5 e 4 e 8 2 Conversion 1 gt Reading 1 Conversion Conversion 20 19 18 17 16 15 14 13 12 11 I gt Reading 2 B Class Average Readings 10 Type Repeating Digital filter types The digital filter can be either a moving or repeating type Filter types are compared in Figure 6 2 Conversion 12 11 10 9 e 3 gt Reading 7 12 e 6 e 5 4 Conversion 3 Conversion 30 29 28 z 5 e D5 an e 24 e 23 22 Conversion 21 Moving Filter Every time a reading conversion occurs the readings in the stack are aver aged to yield a single filtered reading The stack type is first in first out After the stack fills the newest reading conversion replaces the oldest Note that the instrument does not wait for the stack to fill before releasing readings Repeating Filter Takes a selected number of reading conversions averages them and yields a reading It then flushes its sta

Model 6514 System Electrometer Instruction Manual

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