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VT2412-S-11364 - VTI Instruments

1. Command Syntax REC lt record gt lt length gt AE lt record gt number of records lt length gt 256 512 1024 2048 Note The product of the number of records and the record length cannot exceed 2048 Power Up State 1 2048 Query Syntax REC Query Parameters N A Query Response REC lt record gt lt length gt Description The RECord command sets the number and length of the records for the time base selected with the TMBS command The first parameter defines the number of records Integer values from to 8 are valid The second parameter defines the length of the records Valid lengths are 256 512 1024 or 2048 with one restriction the product of the number of records and the record length cannot exceed 2048 the maximum record length All records are the same lengths Specifying a new length or number of records does not affect the breakpoints set in the record s unless the breakpoints are beyond the new record length Existing breakpoints are applied to the new record s automatically If the new record length causes some breakpoints to be beyond the record boundary the invalid breakpoints are deleted and an execution warning message is issued Examples Command Query Response Description REC 2 1024 Sets up 2 records with a length of 1024 each REC REC 2 1024 Verifies there are 2 records with a length of 1024 each VT2412 S 11364 Command Dictionary 99 VXI Technolog
2. Technology VT2412 S 11364 DUAL CHANNEL PROGRAMMABLE DIGITIZER USER S MANUAL P N 82 0044 000 Released October 30 2007 VXI Technology Inc 2031 Main Street Irvine CA 92614 6509 949 955 1894 VXI Technology Inc www vxitech com TABLE OF CONTENTS TABLE OF CONTENTS A a A dais 3 CERTIFICA TION 6 eirinn iris aca dis E vested dis AE van EEEN E GEEET TR E at T tio 6 WARRANTS Oops buasinesib eg dae cedro caro breseestetise 6 LIMITATION OF WARRANTS derrita 6 RESTRICTED RIGHTS LEGEND en 0650543 Teh e EEE cues A ia a 6 DECLARATION OF CONFORMITY ro tia iii E AEE E EEE AAE EE ERE E E E E A a 7 GENERAL SAFETY INSTRUCTIONS miceniene a e an aia e a n 8 TERMS AND SYMBOLS ogeita ia EEN ERER A A EE ENE A EERE TEN e 8 O RN 8 SUPPORT RESOURCES ta a A a A e a TO rl ed 10 SECTION ini didas in de A A TANE EET A 11 INTRODUCTION a ios ios 11 GENERAL DESCRIPTION 0 dr 11 TIME BASES AND DATA MEMORIES viroses teenie in ironia IA a dl cea 12 ANALOG SIGNALS courier e sans 12 INSTRUMENT CONTROL tii A iia c te 13 POWER SUPPLY A GAEREN ETE EAE EE A EARE ERR 13 LODAIN ANCBE RA O A 121 EEE E an E E did 13 VT2412 S 11364 GENERAL SPECIFICATIONS nnna nanen a E R E AE A A E ER ER 14 SECTION Z rosos Ns esteo A NN 15 OJAGA LOINEN EEEE EET A A E A A E A 15 FRONT PANEL FUNCTIONS EAEE E E A E A A 15 Instrument Control FUNCHONS ineen ain e a A E A A E E S AE e 16 Time Base Functions A aes se a e e E A N A da tii 18 Trigger FUNCHONS ii ac
3. Describes the purpose of the command Describes the type of command such as an event or setting Details the exact command format Describes the parameters sent with the command and their legal range Describes the values assumed at power up Details the exact query form of the command Describes the parameters sent with the command and their legal range The default parameter values are assumed the same as in the command form unless described otherwise Describes the format of the query response and the valid range of output Describes in detail what the command does and refers to additional sources Present the proper use of each command and its query when available 64 VT2412 S 11364 Command Dictionary www vxitech com COMMAND DICTIONARY TABLE 4 1 VT2412 S 11364 DIGITIZER COMMANDS INSTRUMENT COMMANDS TMBS Specify the time base to be programmed or queried by subsequent time base commands ARM Arms the time base s specified by the parameter s MTRIG Generates triggers for both channels WRI Enable or disable asserting SRQ when waveform data is readable OFF RQS Enable or disable asserting SRQ to request service ON CLK Select internal or external clock for both time bases INT BTA Enable or disable B Triggerable after A mode OFF REP Set Repeat ARM READ sequence for lt channel gt time base n times
4. ID VXI Query Parameters N A Query Response VXI ID string ID VXI VM2412S Mainframe Firmware AE CPU PFGA Revision Channel A FPGA Revision Channel B FPGA Revision Front Panel FPGA Revision The ID VXI query reports the VXI identification string The string consists of the following information TAL WW XX YY 1 zZ amt i Command Quer Response Description ID VXI VM2412S Mainframe 1 11 01 00 05 00 VT2412 S 11364 Command Dictionary www vxitech com LEV Purpose Set trigger level for selected trigger channel Type Set or Query Command Syntax LEV lt NRI gt ANI lt NR1 gt signed integer Power Up State 0 Query Syntax LEV Query Parameters N A Query Response LEV lt NRI gt Description The LEVel command selects the amplitude level of the trigger signal at which the trigger occurs Valid trigger level values range from 127 to 128 corresponding to the 8 bit resolution of the instrument A setting of 127 means that the time base triggers when the signal reaches full scale amplitude The trigger occurs at the selected point on the positive slope of the waveform if SLOpe is set to POSitive The trigger occurs at the selected point on the negative slope of the waveform if SLOpe is set to NEGative Examples Command Quer Response Description LEV 113 Sets the trigger level to
5. www vxitech com DEP Purpose Put Data in the specified address included for 7612D compatibility only does not actually perform an operation Type Set only Command Syntax DEP H lt address gt H lt data gt AO Eire lt address gt hexadecimal address value lt data gt hexadecimal data value Power Up State N A Query Syntax N A Query Parameters N A Query Response N A Description The first parameter specifies the address into which the data byte will be written A one to four digit hexadecimal number is required preceded by the letter H The second parameter specifies the byte to be written to the specified address A one to two digit hexadecimal number is required preceded by the letter H Note This command is included for 7612D compatibility only it does not actually perform an operation Examples Command Quer Response Description DEP H420 H3F VT2412 S 11364 Command Dictionary 79 VXI Technology Inc DOWNLOAD Purpose Download firmware Type Event Command Syntax DOWNLOAD lt section gt CONAN lt section gt 0 1 2 3 0 GPIB interface code and support software 1 mainframe 2 left channel 3 right channel Power Up State N A Query Syntax N A Query Parameters N A Query Response N A Description The Download command loads new firmware into the VT2412 S 11364 Follow the command
6. ALT Repeats the ARM A READ A ARM B READ B sequence n times REM Enable or disable asserting SRQ when REMOTE is pressed OFF COPY Copy the time base or trigger setting from one channel to another TIME BASE COMMANDS Command Description ela REC Set the number and length of records 1 2048 SBPT Set breakpoint locations and the sampling interval for the segment 0 5e 9 CBPT Clear all breakpoints or the specified breakpoints LTC Select trigger channel sn E MODE Set to pre trigger or post trigger by n samples PRE O TRIGGER CHANNEL COMMANDS Command Description o SRC Select internal or external triggering source INT SLO Set trigger slope to positive or negative POS LEV Set trigger level for selected trigger channel 0 CPL Set trigger coupling to AC or DC AC HFR Enable or disable high frequency reject trigger OFF VT2412 S 11364 Command Dictionary 65 Command TABLE 4 1 CONTINUED DATA TRANSFER COMMANDS Description VXI Technology Inc Power Up State READ Read data from Channel A or B SPECIAL FUNCTION PROPRIETARY COMMANDS Command Description BLANK Enable or disable over range data blanking BLANK BIT Set blanking polarity CAL STORE Commit changes to nonvolatile memory DELAY ARM Set ARM delay DOWNLOAD Download firmware GAIN POT Set channel gain GPIB Set the primary and secondary addresses GPIB TERM Set terminator type ID
7. Description The ALTernate command allows the user to alternately acquire data from Channel A and Channel B with minimal controller intervention Throughput is improved because data can be read from one channel while an acquisition is in progress on the other channel Examples Command Quer Response Description Set to execute alternating channel acquisition five times The sequence is repeated until the instrument receives a device clear interface message 68 VT2412 S 11364 Command Dictionary www vxitech com ARM Purpose Arms the time base s specified by the parameter s Type Set only Command Syntax ARM lt channel gt MeN E eet lt channel gt A B A B B A Power Up State N A Query Syntax N A Query Parameters N A Query Response N A Description The ARM command verifies the time base settings and prepares the channel to accept a trigger Valid parameters are A or B or both A and B listed in any order Examples Command Quer Response Description ARM time base A ARM both time bases VT2412 S 11364 Command Dictionary 69 VXI Technology Inc BLANK Purpose Enable or disable over range data blanking Type Set or Query Command Syntax BLANK lt state gt COIN lt state gt ON OFF Power Up State N A Query Syntax BLANK Query Parameters N A Query Response BLANK ON BLANK OFF Description The Blank
8. Support resources for this product are available on the Internet and at VXI Technology customer support centers VXI Technology World Headquarters VXI Technology Inc 2031 Main Street Irvine CA 92614 6509 Phone 949 955 1894 Fax 949 955 3041 VXI Technology Cleveland Instrument Division 5425 Warner Road Suite 13 Valley View OH 44125 Phone 216 447 8950 Fax 216 447 8951 VXI Technology Lake Stevens Instrument Division VXI Technology Inc 1924 203 Bickford Snohomish WA 98290 Phone 425 212 2285 Fax 425 212 2289 Technical Support Phone 949 955 1894 Fax 949 955 3041 E mail support vxitech com Visit http www vxitech com for worldwide support sites and service plan information 10 VT2412 S 11364 Preface www vxitech com SECTION 1 INTRODUCTION GENERAL DESCRIPTION The VT2412 S 11364 Dual Channel Programmable Digitizer is a microprocessor based waveform digitizing instrument Digitized data is stored in 4k by 8 bits or 2048 words per channel of local memory for subsequent display or data transfer The VT2412 S 11364 uses an IEEE 488 interface for programming and data movement The interface conforms to the IEEE Standard 488 which is commonly referred to as GPIB General Purpose Interface Bus for consistency and ease of programming Local data memory can be partitioned into as many as eight records of equal length These records can then be divided into u
9. is the customer input string which must be enclosed in double quotation marks Example ID My Special Instrument Set GPIB Termination This sets the type of message terminator recognized by the instrument The two choices are EOI or LF The EOI setting uses the GPIB EOI End or Identify signal to indicate the end of the message The LF setting uses a Line Feed character to signal the end of the message Step 1 From the front panel press the LOCKOUT key This results in displaying the Primary address in the Record Length LED display field and the Secondary address in the Samples LED display field Step 2 Press the LOCKOUT key more 4 times in a row Step 3 Press the TRIGGER LEVEL key This will cause the currently selected GPIB termination mode to flash EOI or LF in the TRIGGER LEVEL display window Step 4 Toggle between EOI and LF by using the arrow keys lt lt lt gt gt gt Step 5 Save the selection by pressing the LOCAL key just to the left of the LOCKOUT key This results in saving the GPIB Termination selected to nonvolatile memory and restoring the VT2412 S 11364 to normal operation 26 VT2412 S 11364 Operation www vxitech com Z Blanking Mode on XYZ Output This sets the blanking of data at the upper and lower limits railed data In addition the polarity of the blanking pulse is controlled by this function to allow use of the XYZ display with modern oscilloscopes Step 1 From the front
10. 113 LEV LEV 113 Verifies the trigger level is set to 113 VT2412 S 11364 Command Dictionary 91 VXI Technology Inc LTC Purpose Selects trigger channel Type Set or Query Command Syntax LTC lt channel gt Mew eel lt channel gt L EFT R IGHT Power Up State LTC LEFT for Channel A LTC RIGHT for Channel B Query Syntax LTC Query Parameters N A Query Response LTC LEFT LTC RIGHT Description The Logical Trigger Channel command selects the left or right trigger channel as the trigger source for the selected time base The trigger parameters for the selected trigger channel i e SOURCE SLOpe LEVel and CouPLing are applied to the currently selected time base Both time bases may be programmed to receive their trigger signal from the same trigger channel For example if both time bases are set for the right logical trigger channel both time bases receive the same trigger signal and use the same trigger settings The LTC command provides a convenient way of triggering both time bases simultaneously However when pre trigger mode is selected both time bases must acquire one full record of pre trigger data before becoming triggerable Therefore it is possible for the time bases to trigger at different times although they are receiving their trigger from the same trigger channel If the record lengths trigger modes or breakpoints are different the time
11. 20 POST TRIGGER When pressed the number of records for the selected time base can be set with the DECREMENT INCREMENT buttons The NO OF RECORDS button lights when selected The display shows the number of records for the currently selected time base When pressed a new breakpoint location can be set with the DECREMENT INCREMENT buttons The breakpoint is set in all record s in the selected time base Causes the existing breakpoint s and the corresponding sample interval s to be displayed in the BREAKPOINT LOCATION display The DECREMENT INCREMENT buttons allow the user to cycle through all the existing breakpoints The DISPLAY function also selects the breakpoint to be cleared with the CLEAR function Breakpoints can only be cleared after they are DISPLAY ed Breakpoints can be displayed and cleared from the front panel in local state but they can only be displayed in remote state Clears the breakpoint displayed on the BREAKPOINT LOCATION display The sample interval from the preceding breakpoint is applied to all samples up to the next breakpoint The breakpoint is cleared in all record s in the selected time base Breakpoints must be selected with the display function before they can be cleared Sets the sample interval or external clock period multiplier for all samples after the displayed breakpoint and up to the next breakpoint or the end of the record The display shows the current sample interval or external clock peri
12. CHECKSUM gt Where is the ASCII percent character BYTE COUNT is a 16 bit binary number sent in two bytes most significant byte first The value indicates the number of bytes that remain to be transmitted in the block including the checksum but not including the message unit delimiter semicolon DATA BYTES are 8 bit binary data values in the range of 0 to 255 CHECKSUM is an 8 bit twos compliment binary number that is the modulo 256 sum which is 127 through 128 of all preceding bytes in the block excluding the character 3 is the ASCII semicolon character When data is sent in response to a REP or ALT command all blocks are in this format However EOI is asserted with the message unit delimiter semicolon between ALT or REP cycle only It is not asserted with the semicolon that separates the A and B data blocks For example when waveform data is sent in response to a REP 2 A B command a semicolon separates the A and B data blocks but EOI is not asserted EOI is asserted with each semicolon that separates the block pairs i e the semicolon that follows the B data blocks SET COMMANDS All commands except those listed as Query Only commands can be used as set commands Note that set commands can only be executed in REMOTE state query commands can be executed in either REMOTE or LOCAL state The format for a single set command is lt command gt lt space gt lt parameter gt lt semicolon gt 54 VT2412
13. SBPT command are in seconds The front panel PERIOD indicator lights EXT Selects the external clock signal applied to the rear panel EXT CLK IN connector Sample intervals specified in the SBPT command are external clock multipliers The front panel MULTIPLIER indicator lights When the external clock is selected the instrument multiplies the period of the external clock by the selected multiplier The period of the external clock signal does not to be consistent However the instrument simply divides the input signal so for an external clock period multiplier of 10 a sample is taken every 10 pulse regardless of the individual period of the pulses Examples Command Query Response Description CLK EXT Selects the external clock source CLK CLK EXT Verifies that the external clock source is selected VT2412 S 11364 Command Dictionary 75 VXI Technology Inc COPY Purpose Copy the time base or trigger setting from one channel to another Type Set only Command Syntax COPY lt from_to gt Command Parameters lt from_to gt AB BA LR RL Power Up State N A Query Syntax N A Query Parameters N A Query Response N A Description Examples The COPY command allows the user to copy the setting of one time base or trigger channel to the other time base or trigger channel AB BA LR RL Copy the
14. Set instrument ID ID VXI Query the VXI identification string NV Query model non volatile seed value calibration count and j GPIB primary and secondary addresses SLO GAIN Set Gain DAC SLO OFFSET Query gain offset SN Load a serial number into nonvolatile memory TDAC Load Trigger DAC 66 VT2412 S 1 1364 Command Dictionary www vxitech com TABLE 4 1 CONTINUED QUERY ONLY COMMANDS Query Description SET Returns all settings ERR Returns code for current error condition NBPT Returns number of breakpoints HSF lt CH gt Returns the horizontal scale factors for lt channel gt VSL lt gt Returns the vertical scale factors for the lt gt channel of the left amplifier VSR lt gt Returns the vertical scale factors for the lt gt channel of the right amplifier RDO Returns 40 characters of readout information as acquired from the amplifiers DIAGNOSTIC COMMANDS Command Description DEP Put Data in the specified address FET Fetch Data from the specified address EXEC Begin executing at the specified address VT2412 S 11364 Command Dictionary 67 VXI Technology Inc ALT Purpose Repeats the ARM A READ A ARM B READ B sequence n times Type Set only Command Syntax ALT lt NR1 gt AORTA lt NR1 gt number of times to execute alternate sequence Power Up State N A Query Syntax N A Query Parameters N A Query Response N A
15. The DC level of the signal is ignored and frequencies below about 30 Hz are attenuated DC Select DC coupling of the trigger signal DC coupling provides more stable triggering of low frequency signals Examples Command Query Response Description Selects DC coupling CPL DC Verifies DC coupling VT2412 S 11364 Command Dictionary 77 VXI Technology Inc DELAY ARM Purpose Set ARM delay Type Set or Query Command Syntax DELAY ARM lt numeric_value gt ANI lt numeric_value gt 0 2147483647 Each delay count equals 10 ms e g 1 10 ms 2 20 ms 3 30 ms VXI Technology recommends using values 0 through 5 Power Up State N A Query Syntax DELAY ARM Query Parameters N A Query Response Numeric value Description The Delay Arm command sets the delay from the receipt of the ARM command until the instrument actually arms The value entered represents multiples or 10 ms For example entering a value of 20 would set a delay of 200 ms 0 2 s The default factory setting is 1 As the VT2412 S 11364 is faster than the Tektronix 7612 the delay is used to compensate for this difference For most settings it has been found that a lt numeric_value gt of is adequate Examples Command Query Response Description DELAY ARM 1 Sets the delay to 10 ms DELAY ARM 1 Verifies that the delay is set to 10 ms 78 VT2412 S 11364 Command Dictionary
16. bandwidth A 00 Deflection factors can be manually 09 varied by AA contol Calibrated Variable Gain Returns deflection factors to 20 i calibrated value 00 Probe IDENTIFY switch is pressed O POE ee Probe Attenuation read 04 100X probe 0A 14 10X prob only A write to this address Eee is ignored 1C 1X or un encoded probe VT2412 S 11364 Command Dictionary 117 VXI Technology Inc BW Purpose Selects amplifier bandwidth Type Set or Query Command Syntax BW lt bandwidth gt COIN lt bandwidth gt LIM FUL Power Up State FUL Query Syntax BW Query Parameters N A Query Response BW FUL BW LIM Description The BandWidth command selects the amplifier bandwidth FUL Selects full amplifier bandwidth LIM Selects a limited or reduced bandwidth of 20 MHz Examples Command Quer Response Description Sets amplifier bandwidth to 20 MHz BW LIM Verifies that the amplifier bandwidth is set to LIM 118 VT2412 S 11364 Command Dictionary www vxitech com CPL Purpose Selects the input coupling mode Type Set or Query Command Syntax CPL lt mode gt OMe E eel lt mode gt AC DC GND Power Up State DC Query Syntax CPL Query Parameters N A Query Response CPL AC CPL DC CPL GND Description The CouPLing command selects the input coupling mode of the amplifier AC The AC component of the input signal i
17. been selected and can be cycled through the valid values with the DECREMENT INCREMENT buttons Press and the lt or lt lt button until the value in the record length display decrements to 512 the instrument s default powered up record length is 2048 Press NO OF RECORDS and increment the value to 4 Notice that the number of records will not increment past 4 since four 512 point records fill the entire data memory 2048 points Press SAMPLE INTERVAL and increment the value to 1 us 1E 6 For this example the entire record will be acquired at this sampling interval so no breakpoints are needed Check that the trigger functions are set as follows SOURCE Internal SLOPE Positive COUPLING AC HF REJ Off VT2412 S 11364 Operation 37 10 11 12 13 14 VXI Technology Inc Check that the L TRIGGERED indicator is on If not adjust the trigger level by pressing the TRIGGER LEVEL button Decrement or increment the value and press the TRIGGER LEVEL again to load the new level Pressing any button except DECREMNT INCREMENT ON OFF or LOCAL loads the new value Repeat this procedure until the L TRIGGERED indicator lights and stays on Recheck the settings made in the above steps The settings can be changed as long as the resulting settings do not conflict If they do conflict e g setting the record length to 2048 when 4 records are set up the instrument modifies the settings with record length as hi
18. command enables or disables over range data blanking on the XYZ display The following shows the four possible settings Z Blank Polarity Blank BLNK 1 OFF The Z Blank rear panel output will not blank over ranged data a high low level is generated to blank the display BLNK 0 OFF The Z Blank rear panel output will not blank over ranged data a low high level is generated to blank the display BLNK 1 ON The Z Blank rear panel output will blank over ranged data a high low level is generated to blank the display BLNK 0 ON The Z Blank rear panel output will blank over ranged data a low high level is generated to blank the display Note Blank this command setting Z Blank Polarity BLANK BIT command setting 1 is for working with newer scopes 0 is for working with older scopes TEK7612 compatible Examples Command Query Response Description BLANK ON Enables blanking over range data BLANK BLANK ON 70 VT2412 S 11364 Command Dictionary www vxitech com BLANK BIT Purpose Set blanking polarity Type Set or Query Command Syntax BLANK BIT lt state gt OIEA lt state gt 0 1 Power Up State N A Query Syntax BLANK BIT Query Parameters N A Query Response 0 1 Description The Blank Bit command sets the polarity of the Z blanking signal for the XYZ display The following shows the four possible settings Z Blank Polarity Blank BLNK 1 OFF The Z Blan
19. configuration I hereby declare that the aforementioned product has been designed to be in compliance with the relevant sections of the specifications listed above as well as complying with all essential requirements of the Low Voltage Directive October 2007 lt Q FR gt y E b OS Steve Mauga QA Manager VT2412 S 11364 Preface 7 VXI Technology Inc GENERAL SAFETY INSTRUCTIONS Review the following safety precautions to avoid bodily injury and or damage to the product These precautions must be observed during all phases of operation or service of this product Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design manufacture and intended use of the product Service should only be performed by qualified personnel TERMS AND SYMBOLS These terms may appear in this manual WARNING Indicates that a procedure or condition may cause bodily injury or death CAUTION Indicates that a procedure or condition could possibly cause damage to equipment or loss of data These symbols may appear on the product 1 ATTENTION Important safety instructions Frame or chassis ground WARNINGS Follow these precautions to avoid injury or damage to the product Use Proper Power Cord To avoid hazard only use the power cord specified for this product Use Proper Power Source To avoid electrical overload electric shock or fire
20. gain gt AO lt DAC gain gt floating point number Power Up State N A Query Syntax SLO GAIN Query Parameters N A Query Response floating point number Description The SLO GAIN command sets the Gain DAC This command is used in the calibration of the VT2412 S 11364 Examples Command Quer Response Description SLO GAIN 0 0500 Sets the gain DAC to 0 0500 SLO GAIN 0 0500 Verifies that the Gain DAC is set to 0 0500 VT2412 S 11364 Command Dictionary 107 VXI Technology Inc SLO OFFSET Purpose Type Command Syntax Command Parameters Power Up State Query Syntax Query Parameters Query Response Description Examples Query gain offset Query N A N A N A SLO OFFSET N A Floating point number The SLO OFFSET query reports the gain offset This command is used in the calibration of the VT2412 S 11364 Command Quer Response Description 108 VT2412 S 11364 Command Dictionary www vxitech com SN Purpose Load a serial number into nonvolatile memory Type Set or Query Command Syntax SN lt serial_no gt GIIA lt Serial no gt numeric value Power Up State N A Query Syntax SN Query Parameters N A Query Response Numeric value Description The SN command loads a serial number into nonvolatile memory The number can be up to 31 bits i e 2
21. generate digital trigger signals for the time bases Each time base can be programmed to use either of the trigger channels as a source for the trigger signal At power up time base A is set to receive its trigger from the left trigger channel and time base B is set to receive its trigger from the right channel The user may change these assignments by pressing the SELECT LEFT or RIGHT buttons while setting up the instrument The selected trigger channel is assigned to the time base currently being programmed and all subsequent trigger function entries modify the parameters of that channel All of the trigger functions except LEVEL are selected by pressing a single button on the front panel The trigger level is set by pressing TRIGGER LEVEL and using the DECREMENT INCREMENT buttons to change the value The selected value does not take effect until another button is pressed or the instrument goes to remote state If the trigger channel is receiving a valid trigger the corresponding L or R TRIGGERED light illuminates VT2412 S 11364 Operation 35 VXI Technology Inc Description of Trigger Functions SOURCE COUPLING HF REJ SLOPE TRIGGER LEVEL The source functions selects the internal signal from the amplifiers or external trigger signal as the trigger source In most applications the internal signal from the amplifiers provides an acceptable trigger source The pre and post trigger modes can be used to vary the time re
22. hazard do not use a power source that applies other than the specified voltage Use Proper Fuse To avoid fire hazard only use the type and rating fuse specified for this product 8 VT2412 S 11364 Preface www vxitech com WARNINGS CONT Avoid Electric Shock Ground the Product Operating Conditions Improper Use To avoid electric shock or fire hazard do not operate this product with the covers removed Do not connect or disconnect any cable probes test leads etc while they are connected to a voltage source Remove all power and unplug unit before performing any service Service should only be performed by qualified personnel This product is grounded through the grounding conductor of the power cord To avoid electric shock the grounding conductor must be connected to earth ground To avoid injury electric shock or fire hazard Do not operate in wet or damp conditions Do not operate in an explosive atmosphere Operate or store only in specified temperature range Provide proper clearance for product ventilation to prevent overheating DO NOT operate if any damage to this product is suspected Product should be inspected or serviced only by qualified personnel The operator of this instrument is advised that if equipment is used in a manner not specified in this manual the protection provided by this equipment be may be impaired VT2412 S 11364 Preface VXI Technology Inc SUPPORT RESOURCES
23. microprocessor system The firmware operating system makes the front panel user friendly and allows the programmer to use high level mnemonics to communicate with the instrument over the interface bus Extended IEEE 488 addresses are used so that the VT2412 S 11364 can act as an interface for the programmable amplifiers The logical address may be set locally from the front panel or remotely through the GPIB interface See the Section 2 Operation for information on local control and the Command Dictionary section for remote access via the GPIB interface TIME BASES AND DATA MEMORIES The VT2412 S 11364 has an independent digital time base per channel each controlling a 2k by 8 bit block of memory The output is continuously sampled at 5 ns intervals The time bases select samples from this continuous stream and store them in the waveform memory at the programmed sample rate Each channel time base can be individually programmed to partition their 2k block of memory into one to eight records of equal length Since each record requires a separate trigger to initiate data acquisition several occurrences of a signal may be acquired before data must be read from memory Valid record lengths are 256 512 1024 and 2048 points as long as the total number of points does not exceed 2048 number of records multiplied by the record length lt 2048 Records can further divide into one to fourteen segments each with a programmable sampling interval Th
24. of pre trigger samples and the samples acquired after the trigger fill the record as shown in Figure 2 10 This process is repeated for each record in the channel The pre trigger value is set with the front panel PRE TRIGGER button or with the MODE PRE command in remote state The range of valid values is from zero to sixteen less than the first segment or the record length when no breakpoints are set All pre trigger data is acquired at the sample interval of the first segment Follow these steps to set up pre trigger mode 1 To select the pre trigger mode from the front panel press PRE TRIGGER and DECREMENT INCREMENT to the desired value the power up default value is zero samples Notice that the value cannot be incremented beyond sixteen less than the length of the first segment or record length 2 ARM the selected time base Remember that the instrument acquires one full record of data at the interval programmed for the first segment before becoming triggerable Any triggers that occur during this hold off period are ignored 3 The waveform displayed on the XYZ monitor will be shifted to the right by the programmed number of pre trigger samples The selected number of samples is stored before the trigger event Post Trigger Mode If the targeted signal occurs significantly after the trigger event post trigger can be used to delay the start of acquisition from the trigger In this mode a programmed number of samples are i
25. on the face of the contract VTI specifically disclaims the implied warranties of merchantability and fitness for a particular purpose RESTRICTED RIGHTS LEGEND Use duplication or disclosure by the Government is subject to restrictions as set forth in subdivision b 3 i1 of the Rights in Technical Data and Computer Software clause in DFARS 252 227 7013 VXI Technology Inc 2031 Main Street Irvine CA 92614 6509 U S A 6 VT2412 S 11364 Preface www vxitech com DECLARATION OF CONFORMITY Declaration of Conformity According to ISO IEC Guide 22 and EN 45014 MANUFACTURER S NAME VXI Technology Inc MANUFACTURER S ADDRESS 2031 Main Street Irvine California 92614 6509 PRODUCT NAME Dual Channel Programmable Digitizer MODEL NUMBER S VT2412 S 11364 PRODUCT OPTIONS All PRODUCT CONFIGURATIONS All VXI Technology Inc declares that the aforementioned product conforms to the requirements of the Low Voltage Directive 73 23 EEC and the EMC Directive 89 366 EEC inclusive 93 68 EEC and carries the CE mark accordingly The product has been designed and manufactured according to the following specifications SAFETY EN61010 2001 EMC EN61326 1997 w A1 98 Class A CISPR 22 1997 Class A VCCI April 2000 Class A ICES 003 Class A ANSI C63 4 1992 AS NZS 3548 w A1 8 A2 97 Class A FCC Part 15 Subpart B Class A EN 61010 1 2001 The product was installed into a C size VXI mainframe chassis and tested in a typical
26. order The description is presented in a way to assist the user in the use of each command Every command entry describes the exact command and or query syntax the use and range of parameters and a description of the command s purpose The third part shows both the high level and low level commands for the Programmable Amplifiers The high level command set see Table 4 2 lists the commands by type and includes a brief description of each command The low level code set see Table 4 3 lists the input codes with a description of the corresponding setting The fourth part of this section is devoted to describing each high level command for the amplifiers in detail one per page listed in alphabetical order The description is presented in a way to assist the user in the use of each command Every command entry describes the exact command and or query syntax the use and range of parameters and a description of the command s purpose VT2412 S 11364 Command Dictionary 63 VXI Technology Inc COMMAND DICTIONARY This second part of this section is devoted to the command dictionary for the VT2412 S 11364 Programmable Digitizer Each command is fully described on its own page and the pages are ordered alphabetically In defining how each command is used the following items are described Purpose Type Command Syntax Command Parameters Power Up State Query Syntax Query Parameters Query Response Description Examples
27. output data represents a sine wave but not at the original input frequency Instead it is a sine wave of the same amplitude as the original but with a much longer period time This effect is called aliasing and it can occur with any input waveform though it is more difficult to detect with non sinusoidal waveforms VT2412 S 11364 Operation 47 VXI Technology Inc It is essential to be aware of the potential problems with insufficient sampling A general rule to follow is that the input waveform should be sampled at least twice per period In other words the sample interval should be no longer than one half of the period of the input waveform Of course the higher the sampling rate the more accurately the output data will represent the analog signal ANALOG INPUT SIGNAL NOISE SPIKE LOST DUE TO INSUFFICIENT SAMPLE POINTS NOISE SPIKE PARTIALLY CAPTURED FIGURE 2 15 INSUFFICIENT SAMPLING EXAMPLES 48 VT2412 S 11364 Operation www vxitech com PART A 20KHz ANALOG INPUT SIGNAL e s t I I s s s s s U s e s U s U s t t t t t 6 PART B DIGITIZED DATA WITH SUFFICIENT SAMPLES ACTUAL SAMPLE ALIASED INPUT POINTS OUTPUT SIGNAL AN a DATA N PART C ALIASING FROM INSUFFICIENT SAMPLES FIGURE 2 16 ALIASING EXAMPLE Over range data Full scale vertical deflection for the VT2412 S 11364 correspo
28. process think of a record of VT2412 S 11364 data memory as a pipeline as shown in Figure 2 10 Data is acquired and stored in the waveform memory entering the pipeline from the right As the acquisition progresses new data entering from the right pushes the previous data toward the left end of the pipeline In PRE TRIGGER mode the VT2412 S 11364 begins acquiring pre trigger data shortly after the time base is armed Triggers are ignored during this period Pre trigger data is acquired at the sampling interval selected for the first segment and is stored in the waveform memory pipeline When a full record of pre trigger data has been acquired the time base becomes triggerable but pre trigger data acquisition continues until a trigger is received The new pre trigger data entering the pipeline forces old data out at the other end New data actually overwrites old data in the data memory the pipeline is just an analogy TRIGGER POINT v PRE t TRIGGER gt SAMPLES DATA IN a ONE RECORD gt FIGURE 2 10 PRE TRIGGER ILLUSTRATION 42 VT2412 S 11364 Operation www vxitech com Data is continuously acquired and circulated through the pipeline until a trigger occurs Then data is acquired for each of the segments in the record at the selected sampling interval This data enters the pipeline pushing the pre trigger data to the left The acquisition stops when the selected number
29. required to acquire the pre trigger samples may be different causing one time base to become triggerable before the other Examples Command Query Response Description Selects the left channel or Channel A LTC LEFT Verifies that the left channel A is selected 92 VT2412 S 11364 Command Dictionary www vxitech com MODE Purpose Set to pre trigger or post trigger by n samples Type Set or Query Command Syntax MODE lt mode gt lt N8 gt CONE lt mode gt PRE POST lt N8 gt an unsigned integer multiple of eight Power Up State PRE O Query Syntax MODE Query Parameters N A Query Response MODE PRE lt N8 gt MODE POST lt N8 gt Description The MODE command selects the triggering mode Pre or Post trigger for the selected time base The command parameters specify the trigger mode and the number of pre or post trigger samples to be acquired PRE lt N8 gt Set the instrument to acquire n samples of pre trigger data The number of samples must be an integer multiple of eight from zero to sixteen less than the length of the first segment One full record of pre trigger samples is acquired at the sampling interval of the first segment From this data the programmed number of pre trigger samples is stored the remainder is discarded POST lt N8 gt Set the instrument to acquire n samples of post trigger data The number of samples must be a
30. the DECREMENT INCREMENT buttons The display indicates the trigger level value for the currently selected trigger channel The L or R TRIGGERED indicator lights to indicate that the corresponding trigger channel has received a valid trigger Selects the left trigger channel for programming by subsequent trigger function entries Also causes the left trigger channel to be used as the trigger source for the time base currently being programmed The trigger level for the left channel is displayed in the TRIGGER LEVEL display Selects the right trigger channel for programming by subsequent trigger function entries Also causes the right trigger channel to be used as the trigger source for the time base currently being programmed The trigger level for the right channel is displayed in the TRIGGER LEVEL display Selects internal or external source for the trigger signal The INT EXT button lights when INTernal is selected 20 VT2412 S 11364 Operation www vxitech com 26 27 28 29 30 MAN TRIG AC DC HF REJ Causes the currently armed channel s to trigger MAN TRIG does not affect the trigger function settings One record of data is acquired for each MAN TRIG If multiple records are selected one MAN TRIG per record is required to manually complete acquisition Sets the selected trigger channel to trigger on the positive slope of the waveform The button lights when selected Sets the selected trigger chann
31. with data from an S record file Examples Command Query Response Description DOWNLOAD 1 Downloads firmware into the mainframe section of the VT2412 S 11364 80 VT2412 S 11364 Command Dictionary www vxitech com ERR Purpose Returns code for current error condition Type Query only Command Syntax N A AO N A Power Up State N A Query Syntax ERR Query Parameters N A Query Response ERR lt NR1 gt Description The ERRor query returns a numeric error code in NR1 notation if an error has occurred since the last ERR query If no error has occurred the code is zero The error code is not cleared by executing a valid command the code is unchanged until another error occurs or the ERR query is executed See Warning and Error Messages in Section 3 Examples Command Quer Response Description ERR 0 Returns that no errors have occurred VT2412 S 11364 Command Dictionary 81 VXI Technology Inc EXEC Purpose Begin executing at the specified address included for 7612D compatibility only does not actually perform an operation Type Set only Command Syntax EXEC H lt address gt AN lt address gt hexadecimal address value Power Up State N A Query Syntax N A Query Parameters N A Query Response N A Description The parameter is a one to four digit hexadecimal address preceded by the let
32. 1 Maximum number of breakpoints exceeded 202 Negative argument invalid 203 Argument out of range 204 Invalid record length 205 Conflicting arguments 206 Invalid sampling interval or external clock period multiplier TABLE 3 7 INTERNAL ERROR MESSAGES peated DESCRIPTION 302 RAM failed self test 303 Interrupt fault 304 Checksum error found in ROM 305 Data transmitter failed to begin or complete in allotted time MESSAGE NUMBER TABLE 3 8 POWER FAIL ERROR MESSAGE DESCRIPTION 401 Power failure is imminent VT2412 S 11364 Programming 61 VXI Technology Inc 62 VT2412 S 11364 Programming www vxitech com SECTION 4 COMMAND DICTIONARY INTRODUCTION This section presents the instrument command set in three parts as follows A listing of the commands for the VT2412 S 11364 Programmable Digitizer Detail descriptions of the commands for the VT2412 S 11364 Programmable Digitizer A listing of the commands for the Programmable Amplifiers Detail descriptions of the commands for the programmable Amplifiers The first part is a listing of the instrument specific or device dependent commands for the VT2412 S 11364 Programmable Digitizer see Table 4 1 The list is grouped by command type and includes a brief description of each command function The second part of this section is devoted to describing each command for the VT2412 S 11364 in detail one per page listed in alphabetical
33. 11364 Command Dictionary www vxitech com NBPT Purpose Returns number of breakpoints Type Query only Command Syntax N A ON N A Power Up State N A Query Syntax NBPT Query Parameters N A Query Response NBPT lt NR1 gt Description The NBPT query returns the number of breakpoints currently set in the selected time base The value returned is in NR1 format Examples Command Quer Response Description NBPT 4 Returns that there are 4 breakpoints set in the selected time base VT2412 S 11364 Command Dictionary 95 VXI Technology Inc NV Purpose Query model non volatile seed value calibration count and GPIB primary and secondary addresses Type Query Command Syntax N A Command Parameters N A Power Up State N A Query Syntax NV Query Parameters N A Query Response Model non volatile seed value calibration count and GPIB primary and secondary addresses Description Examples Command Quer Response Description The NV query reports the model non volatile seed value calibration count and GPIB primary and secondary addresses Model VT2412 S 11364 Seed 2 CalCount 20 Primary 1 Secondary 2 96 VT2412 S 11364 Command Dictionary www vxitech com RDO Purpose Type Command Syntax Command Parameters Power Up State Query Syntax Query
34. 612D MECHANICAL Mechanical design compatible with the Tektronix 7612D SHORT CIRCUITING THE ACTUATE Je OFA SARE a E a TO PRNEPAL POWER SoM 1 2 3 4 AEN A Y Y j Y THEN APPEARS AT THE ENABLE ANALOG DISPLAY E pai iB 0 Q Al XAXIS CLOCK OUT EXTCLOCK LEFTTRIG RIGHT TRIG 1 INPUT INPUT INPU A 500HMS 50 OHMS DS ECL COMPATIBLE 40V PEAK MAX 0 5W AC LINE FUSE D 3A250V SLO BLO _ ZAXIS D IEEESTD 488 PORT NONA A A W Oh VOLTAGE AC POWER SELECT INPUT iy VXI Technology Inc woo nono y EX D FIGURE 1 2 VT2412 S 11364 DUAL CHANNEL PROGRAMMABLE DIGITIZER REAR VIEW 14 VT2412 S 11364 Introduction www vxitech com SECTION 2 OPERATION This section describes the operation of the VT2412 S 11364 and the Programmable Amplifiers It is divided into front panel functions essential instrument settings to get started rear panel connections followed by detailed operating procedures FRONT PANEL FUNCTIONS The VT2412 S 11364 front panel controls and indicators are divided into four main function sets Instrument Control Functions Controls the basic functions of the VT2412 S 11364 such as powering on and off clock source and copying values from one time base to another Time Base Functions The time base controls program the time bases for memory partitioning sample intervals and pre and post trigger modes Trigger Functions The trigger controls program the trigger level so
35. A CAL STORE command is required to save this setting in non volatile memory Examples Command Quer Response Description SN 1234 Load serial number CAL STORE Store the new setting in nonvolatile memory SN SN 1234 Reports serial number VT2412 S 11364 Command Dictionary 109 VXI Technology Inc SRC Purpose Select internal or external triggering source Type Set or Query Command Syntax SRC lt source gt OREA lt source gt INT EXT Power Up State INT Query Syntax SRC Query Parameters N A Query Response SRC INT SRC EXT Description The SouRCe command selects the trigger source for the selected trigger channel INT Select the internal trigger signal from the amplifier as the trigger source This signal usually provides adequate triggering for most normal application EXT Select the signal applied to the rear panel L or R TRIG connector as the signal source Examples Command Query Response Description SRC EXT Selects the external trigger source SRC SRC EXT Verifies that the external trigger source is selected 110 VT2412 S 11364 Command Dictionary www vxitech com TDAC Purpose Load Trigger DAC Type Set Command Syntax TDAC lt dac_value gt OMEN eevee lt dac_value gt floating point number Power Up State N A Query Syntax N A Query Parameters N A Query Response N A Description Th
36. AR Mi A A e O EAR sia de 78 DEP n A AAR E A ee are ee 79 DOWNLOAD Vta RE A E E A ET EA 80 PERI Docs a da TE DATO Lt TETEE E ATES 81 DDA A OEE A dd E TER E den a E ad e OES ae EEEE T 82 Ded NN 83 GAIN PO Tiida ala tion vended ae LEE NEN ED LAA EE EEE UREA a Se dat tee Ea 84 A NO 85 GPIB LERMA toto A AST eto Ral da A ai Pens AR blo Re 86 HER A A A A AT a REO 87 TIS ES Cee E E E E AEE E A A Tas oe eae Rue 88 Di A E RES EEG eo ba BREE ha TA a RE 89 D VX renint hea A ARER ude Paks tak ORR Fives O A E ee eeG Nba Cece A E ERRANA 90 A EERS SEER E IA OE E IEA O E ETA IRE E E 91 RI 92 MODE cdi 93 A A NN 94 NB acaso sida ESTS 95 Na le EIS AEE EEE rte TN e la E a il car IR Mee eo o el 96 15 0 6 yes ete O 97 READ o AE A Re LT OS i i OI Rohit Bee 98 REC oi ses Beets e O A ROE RLSM le Rc aa Ne 99 REM A NN 100 RE A IN Ne SA 101 ROSA tate ad Pd O A A A A td 2 ad o ao ted ose 102 4 VT2412 S 11364 Preface www vxitech com SBP Direo ran cus is aso kg ase Coon eg cia ccda 103 A O ARE CORT 105 S E O ese a A A TERUG ak GEE E ED A BEES Gp PETES A EE 106 SE OsGAUIN ci hes a aks ood a one a oe cde cits Pot edit coda te oe ita stn Pe Rios A Toes Ao 107 SLO OFFSET ca E eee aT aN EI SB EE OE ed ob Res 108 Ni A Weal one DE ad e nee 109 A NN 110 TDA Ci ea ci 111 BAY IB fe ae Renee A eS A Ean PELE DR a O 112 Me He Bsa iss ote sete ts re ss tra dik Ls tated tat Mash II ds Ale A e Lasts A de oda As 113 VIRAL e eee ea ed dae 114 Mo Me ew E REA 115 PROGRA
37. Because the processor and the GPIB interface of the VT2412 S 11364 are fast at handling GPIB commands the user can adjust the arm delay to closely match their individual situation Step 1 From the front panel press the LOCKOUT key This results in displaying the Primary address in the Record Length LED display field and the Secondary address in the Samples LED display field Step 2 Press the LOCKOUT key 4 times in a row Step 3 Press the NO OF RECORDS key This will result in the display of ARM DELAY setting for the selected channel RECORD LENGTH NO OF RECORDS BREAK POINT LOCATION SAMPLE INTERVAL PERIOD MULTIPLIER SET DISPLAY CLEAR Step 4 Set the desired delay by using the arrow keys lt lt lt gt gt gt NOTE Each delay count is worth 10 ms VT2412 S 11364 Operation 29 REAR PANEL CONNECTIONS VXI Technology Inc The back panel control and connectors are shown in Figure 2 5 followed by detailed descriptions 3 4 5 6 7 8 9 10 CLOCK OUT EXTCLOCK LEFTTRIG RIGHT TRIG INPUT INPUT INPUT 50 OHMS 50 OHMS ECL COMPATIBLE 40V PEAK MAX 0 5W VXI Technology Inc SHORT CIRCUITING THE ACTUATE RE EMOTE OE CONNECTOR APPLIES POWER TO PRINCIPAL POWER SWITCH AN THIS DEVICE A SHORT CIRCUIT ANALOG DISPLAY y En ONI AN a X AXIS Y AXIS ACLINE FUSE Y 3A250V SLO BLO _ J ZAXIS IEEE STD 488 PORT VOLTAGE AC POWER SELECT INPUT
38. CQUIRE PRE TRIGGER DATA BEGIN AQUISITION FIGURE 2 6 ARM PROCESS FLOW CHART 34 VT2412 S 11364 Operation www vxitech com Acquiring a Base Line 1 Connect a compatible XYZ monitor to the VT2412 S 11364 2 Power up the VT2412 S 11364 and allow it to warm up for 5 minutes 3 Turn on the monitor and set it for normal intensity 4 Ground the inputs of programmable amplifiers 5 Press ARM A and ARM B simultaneously The ARM buttons should light indicating that the instrument is armed and triggerable 6 Press MAN TRIG to trigger the time bases The instrument acquires one record of 2048 samples for each channel Two flat lines should appear on the XYZ monitor and the ARM buttons should extinguish 7 If the base lines do not appear check the connections and adjustments of the monitor Then re ARM the time bases and press MAN TRIG again 8 If the lines still do not appear check the Position controls on the programmable amplifiers and repeat the previous step Setting the Trigger Functions The VT2412 S 11364 has two independent trigger channels Triggering parameters such as level slope source and coupling can be individually programmed for each trigger channel The trigger channels receive analog trigger signals from the programmable amplifiers an external source or the MANual TRIGger button on the front panel If the programmed trigger conditions are met the trigger circuits
39. D 1 E 0 Verifies the 1 V per division setting VT2412 S 11364 Command Dictionary 129 VXI Technology Inc APPENDIX A FRONT PANEL OVERLAY 2412 PROGRAMMABLE DIGITIZER VXI Technology 130 VT2412 S 11364 Appendix A www vxitech com COUPLING s ti Uae enti Aiea cubes aha eaves oe 36 CPE sra a aE A TETI 65 77 116 119 D data Dni 54 data Memory ii dase ER E ETRE 11 DELAY ARM os ciscesscsisccsessgsnsisncssnesaea tusersasvesrecaentaescpsueneseansvanees 66 78 delimiter DEP ios DOWNLOAD E P PALAIS tE Fs RATO 52 55 PU aa Ra iaa 12 POL 116 123 POS 116 124 POWEL SUPPI alii a na 13 PRB nuse renato 116 125 programmable amplifier ooocncncicnnnnncnnncnnnconnnconnnccnncnnnncnnnos 12 13 query command cir 56 57 Dd ds e ues 66 89 116 120 ID VXI 66 90 116 121 INP 116 122 interface bus 12 51 Antertial CLOCK AAA TR ieee 11 SBP Evisos segment set command ace SED bees TO 67 10 symbols O E ST S T VT2412 S 11364 Index 131 VXI Technology Inc T GA tE ERAEN ERR 67 114 VRT nen reton EEEN EEA 13 W AA OA E E 54 word serial command cceesceseeseeseeseeseeseeseeececseeeseeseeseeseeseeaeenes 12 V WERT eee Se bcc A Ste edo ES E ESA 65 115 VDD otek EEE Les SE REE a kh 116 129 X VAR earainn E OE ER E E 116 128 gt a 67 113 XYZ display sssseeeeesessssssesesnssesesnseeessseresnseeesssee
40. I Technology Inc PROGRAMMABLE AMPLIFIER COMMANDS TABLE 4 2 AMPLIFIER HIGH LEVEL ASCII COMMAND SET SET COMMANDS Command Description eee INP Selects the input connector A RIN Selects amplifier input impedance HI CPL Selects the input coupling mode DC BW Selects amplifier bandwidth FUL POL Selects amplifier polarity NOR V D Set the volts per division range 5 POS Controls the vertical position of the trace 0 VAR Enable or disable variable amplifier gain OFF ID Set instrument ID N A Command Description PRB Query the probe setting on the selected input ID VXI Query the VXI identification string SET Query the settings of the input amplifier 116 VT2412 S 11364 Command Dictionary www vxitech com TABLE 4 3 AMPLIFIER LOW LEVEL HEXADECIMAL CODES Address Parameter Setting Description 00 16 Amplifier ID read only 01 ue A Input Connector 40 B 80 50 Q 02 00 i Mo Input Impedance 00 AC 03 10 DC Input Coupling 20 GND 05 10 mV div 04 20 mV div 06 50 mV div 01 100 mV div ee 04 00 200 mV div Vols Division ignores probe attenuation 02 500 mV div 09 1 V div 08 2 V div 0A 5 V div 05 High two bits of Position 03 FF 10 22 divisi divisions Low eight bits of Position 06 02 00 Midscreen nee Step size is 0 02 div 00 00 10 24 divisions 07 00 Inverted Polarity 08 Normal 00 20 MHz limit B idth Limit Ed 40 Full
41. MANual TRIGger will not trigger time base B until this condition is satisfied Selects the internal or external clock as the clock source for both channels When set for INTernal the CLK button lights and the SAMPLE INTERVAL function selects a sample period in seconds When set for EXTernal the SAMPLE INTERVAL function selects a period multiplier for the externally supplied clock signal Allows the user to decrement or increment the current values for a selected time base or trigger parameter The value is only decremented or incremented through valid values and does not wrap around When the value reaches its upper or lower limit it stops For example to set a new record length the user presses RECORD LENGTH to modify that value using the decrement increment buttons The value can be cycled through all the valid settings for RECORD LENGTH If any other button other than DECREMENT INCREMENT ON OFF or LOCAL is pressed the new value is entered If the instrument goes to remote state before another button is pressed the previously selected value is automatically entered The lt lt and gt gt buttons cause the value to decrement increment at a faster rate than the lt and gt buttons VT2412 S 11364 Operation 17 10 REMOTE 11 LOCAL 12 LOCKOUT Time Base Functions VXI Technology Inc The REMOTE button lights when the VT2412 S 11364 is set to remote state by the bus system controller When REMOTE is pressed an
42. MMABLE AMPLIFIER COMMANDS sscccsssssesesssseecessseeessnseececsceecessueeecseaeesecsueeecsesaeeecsasesecsueeessssaeeseneaaees 116 Bi Ba ates soa tes de an het cits cases settee besten ATE E EE ot lancet E AT ies Saito to 118 Gece ie A O Satie Mit eet is Mes costae Sons AU A TOS NE 119 Diino Ssh la Ria eR ea he asin es 120 IN oe hes ee O ghee OGLE HERS es a RN ATES Bao a as Os EERO TRG Recs Sa 121 DNP a a AAA EE Ee EN tc Reh ti ii Es 122 PO Doss econ NN 123 BOS oie cds e AE E O EERIE Ld Fade nt att ne PAD a o fake fetes SoMa Sat Eolo 124 PRIB Pace ae lado e a boat TE aed aR a ee e dd el 125 RIN ass 5 Fest A a e o aS 126 I Deg a EAE E E O E IAEE SE S RN 127 O NO 128 570A DETERE AERE Seite e ao clado re ld o Et e dr ld O 129 APPENDIX A FRONT PANEL OVERLAY iii ds 130 A NAT 131 VT2412 S 11364 Preface 5 VXI Technology Inc CERTIFICATION VXI Technology Inc VTI certifies that this product met its published specifications at the time of shipment from the factory VTI further certifies that its calibration measurements are traceable to the United States National Institute of Standards and Technology formerly National Bureau of Standards to the extent allowed by that organization s calibration facility and to the calibration facilities of other International Standards Organization members WARRANTY The product referred to herein is warranted against defects in material and workmanship for a period of one year from the rec
43. NRFD NDAC 11 12 13 FIGURE 2 5 REAR PANEL CONNECTORS 1 CLOCK OUT 2 EXT CLOCK INPUT 3 1 2 3 4 Connectors 4 LEFT TRIG INPUT 5 RIGHT TRIG INPUT The ECL level internal clock signal is available at this connector This output is active in external or internal clock modes An ECL level external clock signal applied to this connector drives the A and B time bases when external clock is selected Rear panel connectors 1 2 3 and 4 provide straight through connection to the front panel connectors 1 2 3 and 4 respectively Input connector for the left channel external trigger signal Terminated in 50 Q Input connector for the right channel external trigger signal Terminated in 50 Q 30 VT2412 S 11364 Operation www vxitech com ACTUATE ENABLE AC LINE FUSE PRINCIPLE POWER SWITCH X Y Z AXIS VOLTAGE SELECT AC POWER INPUT IEEE STD 488 PORT A TTL low applied between the center conductor and outer conductor turns the VT2412 S 11364 power supply on Applies a TTL low between center conductor and outer conductor shortly after the instrument is powered up This allows the power control of the VT2412 S 11364 to be daisy chained with other similar instruments in a system Replaceable fuse for AC line Use 3 A 250 V SLO BLO fuse Power line switch that controls line input power to the VT2412 S 11364 power supply Provides X Y Z analog equivalents of the waveform data st
44. Parameters Query Response Description Examples Returns 40 characters of readout information as acquired from the amplifiers Query only N A N A N A RDO N A RDO lt CHARACTER S gt The RDO query returns 40 characters of readout information as acquired from the amplifiers The readout information is in ASCII and is divided into four fields one for each channel of each amplifier The readout is returned as it is acquired from the amplifier Consequently some special characters may be replaced by ASCII characters The readout is returned enclosed in quotation marks as shown with spaces separating the fields Empty fields are filled with spaces Command Quer Response Description a RDO lt left ch 1 gt lt left ch 2 gt lt right ch 1 gt lt right ch 2 gt RDO VT2412 S 11364 Command Dictionary 97 VXI Technology Inc READ Purpose Read data from Channel A or B Type Set only Command Syntax READ lt channel gt lt record gt segment gt OIEA lt channel gt A B lt record gt record number lt segment gt segment number Power Up State N A Query Syntax N A Query Parameters N A Query Response N A Description The READ data command causes the instrument to transmit waveform data to the controller The entire contents of one channel may be transmitted or a record or segme
45. Parameters N A Query Response RQS ON RQS OFF Description The ReQuest Service command enables or disables the SRQ function of the instrument Examples Command Query Response Description RQS OFF Disables asserting SRO to service request RQS RQS OFF Verifies that asserting SRO to service request is disabled 102 VT2412 S 11364 Command Dictionary www vxitech com SBPT Purpose Type Command Syntax Command Parameters Power Up State Query Syntax Query Parameters Query Response Description Set breakpoint locations and the sampling interval for the segment Set or Query SBPT lt N8 gt lt NR3 gt lt N8 gt lt NR3 gt lt N8 gt unsigned integer multiple of eight lt NR3 gt signed scientific notation 0 5e 9 SBPT N A SBPT lt N8 gt lt NR3 gt lt N8 gt lt NR3 gt The Set BreakPoinT command sets the breakpoints and sampling interval for all records in the selected channel A breakpoint divides the records into segments A segment includes all the samples from the specified breakpoint to the next breakpoint or the end of the record Each segment has an independent sampling interval All records are identical so breakpoints apply to all records in the currently selected channel The SBPT command parameters are specified in pairs The first parameter defines the breakpoint location The location is specified as a sample number and it must
46. S 11364 Programming www vxitech com More than one parameter is required for several commands such as REC set the number and length of records For example REC lt space gt lt parameter gt lt comma gt lt parameter gt lt semicolon gt The SBPT command set breakpoint and sampling interval requires at least two parameters and may have as many as twenty eight Again commas separate the parameters Examples of single set commands are TMBS A SBPT 128 1 e 6 496 3 e 8 READ A 1 4 More than one set command can be sent as part of a single message if the commands are separated by semicolons This requires the following syntax lt set command gt lt semicolon gt lt set commands lt semicolon gt lt set command gt lt semicolon gt An example of multiple set commands in a single message is TMBS A TRIG RIGHT REC 4 512 ARM A Multiple READ commands may also be included in a message with other commands However the instrument must be addressed to talk for the response to each READ command For example the following message might be sent to the instrument REC 4 512 ARM A READ A READ A 3 TMBS B The instrument sets the number and length of records and arms time base A The first READ command is buffered and the instrument waits for Channel A s acquisition to complete Then it expects to be addressed to talk the talk address may be sent while the acquisition is in progress The instrument begins sending the data acqu
47. VT2412 S 11364 time bases The clock source is selected with the front panel CLK function When the button is dark the external clock signal is selected when the button is lit the internal clock signal is selected The selected clock source applies to both channels they are not separate When the external clock is selected the MULTIPLIER indicator lights indicating that the SAMPLE INTERVAL function selects a period multiplier for the external clock signal For example if a 1MHz 1 us period clock is applied selecting a period multiplier of 1 results in a 1 us sampling interval A multiplier of 1000 1E 3 results in a 1ms sampling interval The effective sampling interval is calculated as follows SI External Clock Period x External Clock Period Multiplier VT2412 S 11364 Operation 45 VXI Technology Inc The external clock input allows the VT2412 S 11364 to synchronously sample a signal with respect to the externally supplied clock The period of the clock signal need not be consistent However the period multiplier divides the external clock therefore for a period of 10 a sample is taken on every 10 pulse regardless of the period of the individual pulse The external clock period multiplier is set by pressing the SAMPLE INTERVAL button and using the DECREMENT INCREMENTS buttons to set the desired value The range of valid values is 1 to 200 x 10 Local Control in a Bus Interface System When the VT2412 S 11364 is
48. a dual channel amplifier is not installed VT2412 S 11364 Command Dictionary 113 VXI Technology Inc VSR lt gt Purpose Returns the vertical scale factors for the lt gt channel of the right amplifier Type Query only Command Syntax N A ON N A Power Up State N A Query Syntax VSR lt gt Query Parameters lt gt 1 2 Query Response See below Description The Vertical Scale factors query returns the scale factors for the RIGHT amplifier Channel B Examples Command Quer Response Description VSR1 500 e0 3 V CAL VSR2 NONE Selecting lt 2 gt as the parameter will report back NONE if a dual channel amplifier is not installed 114 VT2412 S 11364 Command Dictionary www vxitech com WRI Purpose Enable or disable asserting SRQ when waveform data is readable Type Set or Query Command Syntax WRI lt state gt CONAN lt state gt ON OFF Power Up State OFF Query Syntax WRI Query Parameters N A Query Response WRI ON WRI OFF Description The Waveform Readable Interrupt command enables or disables the SRQ interrupt generated when a channel completes its acquisition Examples Command Query Response Description Enables asserting SRO when waveform data is readable WRI ON Verifies that asserting SRO when waveform data is readable is enabled VT2412 S 11364 Command Dictionary 115 VX
49. aecida 20 Programmable Amplifier Functions ccccesccesecssecsceeseeescescecaeeeseceneeeceseenseceseceaeeaecsaecnaecseecaeeeaeeeneeneeeereeas 22 INSTRUMENT SETTINGS ENERE E a Staeti sites takes seucuaseteadages E dae 24 Set GPIB Primary Address lala 24 Set GPIB Secondary A ddr dd 25 St Product Di aiii 26 Set GPIB Terminations ii A e aid at hea 26 Z Blanking Mode on XYZ Output r e a e a a e a a E a AE RR 27 Set Channel Gai AA E TA E E E E E RS 28 SetArm Delayer n A T AU Rete E ete etn aS 29 REAR PANEE CONNEGTIONS maesa oiri AEA T E EE ASEN IAEE OTA RE 30 OPERATING PROCEDURES neirens iiien i E K EREIN E EE E EE E N RAEE 32 XYZ DA E EA A E E A E ai 32 Applying Power E AEE E E E A E E E E SATE 32 The Acquisition P O A a aa E E A R a EE E E aE SEE Eea 32 Arming the Time Baseren E E R tt 33 Acquiring a Basi E A E E EE E E REE R E 35 Setting the Trigger Functions iii aii a EE E E R A REE e asii 35 Description of Trigger Functions cccceesceeceescesecesecsecseecseecseeeaeeeneeecesecesecsecsecaecsaecaaecseecaeeaaecneeeaesentenes 36 Setting up a Simple Acquisition Program sssessesessseessssteressesesesteressestessestestestestsseetessestesteseesessesressesets 37 Setting BEAM e Roe 39 COPY A A O EO V ENE E E na 42 Pre Trigger Mode tdci 42 Post Ttigaer Mode E A O e O 43 B Triggerable After A MOde ccccecccesscesscessceeecesecesecsaecseecseeeaeeeaeseneeeeeseenseceeceaecnaecnaecaaecaeesaeseneeeneeneeenreees 45 Extern
50. al Clock ao td ares el tc 45 Local Control in a Bus Interface System t e E E EE E E 46 Acquiring Data ii dada 46 VT2412 S 11364 Preface 3 VXI Technology Inc JA O 51 PROGRAMMING is 51 INTRODUCTION PE EE A e O SPR A hos Eres tesa 8 51 TEEE 488 INTERFACE Sado dto hie thle La ARAM Aoi kell eet E mai lod 51 IEEE Interface Function Subsets abate 51 COMMAND SITAS es 52 NUMBERS ico 53 WAVEFORM DATA VO La o ns A add A ee DA 54 SET COMMANDS 2 o E E EEE 54 QUERY COMMANDS tii A a a aida 56 INSTRUMENT STATUS Forta A O Rs DEA 57 Device Dependent Status iiiss caccsccccc cescccciesivectecsee siete cciee cat eecei ccc dactecsteedeeddadudeudn sand eucdedeeseceseedgicvaceies ostsatdveess 58 WARNING AND ERROR MESSAGES csscccsssssssecssececessuececsesaececsneeecsesaececsesaeeecsneeecessaeeecseaaesecaeeeseesaeeecsesaeeeeneeeenes 59 Warning MESSa A A EE 59 ON 60 JOA NN 63 COMMAND DIGTIONARY ccoo dadas ct lc do leia lts ios Men de e tela db les odo le 63 INTRODUCTION tl iia 63 COMMAND DICTIONARY si ad cade 64 COMMAND DICTIONARY lt a A A et SR ee aed 65 ATED RN 68 PAR Mere Macs A SR A ST See ee Se is ed Ne 69 BLANK ie Obstet ick om hacer te Maat ia bins AL e tase ti foes dae tote Seas a Sashes 70 BLANK BE e a e el e Es Se e 71 BA Nit 72 CAE STORE oe ac vsc dads seven soeaien cesses Coatce 220s tatiana aaa an din eee e 73 BPE A A 0 EEE RTE Ch aa 74 A O o O O 75 COPY di ir e Dl a er 76 CPE A a e e Sie Cees Race Te ea eh ove wate 77 DELAY
51. arned programmable settings For example the user may wish to set the instrument up from the front panel and write an application program that learns the settings when the REMOTE button is pressed These settings can be restored at any time by sending the string stored from the query response Examples Command Quer Response Description CLK INT BTA OFF WRI OFF RQS ON REM OFF TMBS A REC 1 2048 SBPT 0 5e 9 MODE PRE 0 LTC LEFT SRC INT SLO POS HFR OFF CPL AC LEV 0 TMBS B REC 1 2048 SBPT 0 5e 9 MODE PRE 0 LTC RIGHT SRC INT SLO POS HFR OFF CPL AC LEV 0 This example shows all the settings at power up VT2412 S 11364 Command Dictionary 105 VXI Technology Inc SLO Purpose Set trigger slope to positive or negative Type Set or Query Command Syntax SLO lt slope gt OIE lt Slope gt POS NEG Power Up State POS Query Syntax SLO Query Parameters N A Query Response SLO POS SLO NEG Description The SLOpe command selects the slope on which the time base triggers The LEVel parameter selects the point on the selected slope at which the trigger occurs Examples Command Query Response Description SLO NEG Sets the trigger slope negative SLO SLO NEG Verifies that the trigger slope is set negative 106 VT2412 S 11364 Command Dictionary www vxitech com SLO GAIN Purpose Set Gain DAC Type Set or Query Command Syntax SLO GAIN lt DAC
52. be a multiple of eight from sixteen to eight less than the record length except for the fixed breakpoint at location zero If the specified location is not a multiple of eight the number is rounded to the next lower multiple of eight and an execution warning message is issued The second parameter defines the sampling interval associated with the breakpoint The sampling interval applies to all samples from the existing breakpoint to the next breakpoint or the end of the record The range of valid sampling interval values depends on the selected clock source When the internal clock source is selected front panel CLK button lit sampling intervals range from 1 s to 5 ns and are given by the formula S I 5 ns X 10 Where X 1 2 4 6 20 Y 0 1 7 When the external clock source is selected the sampling interval parameter represents an external clock period multiplier The period of the signal applied to the rear panel EXT CLK connector is multiplied by the selected external clock period multiplier Valid values range from 1 to 200 x 10 and are given by the formula VT2412 S 11364 Command Dictionary 103 VXI Technology Inc SBPT Continued S I EXT CLK X 10 Where X 1 2 4 6 20 Y 0 1 7 Again if the value specified in the command parameter is within the valid range but does not conform to the formula the instrument sets it to the next lower valid period multipli
53. bus for instrument systems Referred to as the interface bus in this manual the IEEE 488 bus is also known as the General Purpose Interface Bus GPIB The interface bus uses eight data and eight control lines Information is transferred bit parallel byte serial by an asynchronous handshake The VT2412 S 11364 Programmable Digitizer has both listener and talker functions as defined by the standard See JEEE Standard 488 1978 for more information IEEE 488 INTERFACE The VT2412 S 11364 can be operated by remote control over the IEEE 488 interface bus GPIB The VT2412 S 11364 is fully programmable all front panel functions except ON OFF can be controlled over the interface bus The VT2412 S 11364 is fast waveform data can be output at the maximum rate allowed by the listener Commands are simple and mnemonic simplifying the programming task The VT2412 S 11364 also provides an interface between the IEEE 488 bus and the programmable amplifiers In effect the IEEE 488 bus is extended to the amplifiers through the VT2412 S 11364interface The interface and commands for the amplifiers are discussed in the Command Dictionary section IEEE Interface Function Subsets IEEE Standard 488 1978 identifies the interface functions of a device on the bus in terms of interface function subsets These subsets are defined in the standard The subsets that apply to the VT2412 S 11364 are shown in Table 3 1 How these functions are implemented is explai
54. d READ commands the specified number of times for the specified channel s Two parameters are required The first parameter is a number in NR1 format that specifies the number of times the ARM and READ sequence is repeated If this parameter is set to zero 0 the instrument continues to repeat the sequence until it receives a device clear interface message A negative number results in a command error The second parameter specifies the channel s that will execute the ARM and READ sequence A Repeat the sequence ARM A READ A the specified number of times B Repeat the sequence ARM B READ B the specified number of times A B or B A Repeats the ARM A B READ A READ B sequence the specified number of times The waveform data is sent from Channel A first then from Channel B with a semicolon separating the binary data blocks All waveforms are sent in the binary block form with blocks separated by semicolons If the instrument is addressed to talk before an acquisition is complete data is transmitted when the acquisition completes Command Query Response Description Repeats the ARM A READ A sequence for REP 4 A times VT2412 S 11364 Command Dictionary 101 VXI Technology Inc ROS Purpose Enable or disable asserting SRQ to request service Type Set or Query Command Syntax RQS lt state gt COIN lt state gt ON OFF Power Up State ON Query Syntax RQS Query
55. d the system controller has enabled the Remote Request function REM ON command the VT2412 S 11364 requests service from the controller and reports remote request status Returns the VT2412 S 11364 from remote state to local state unless the system controller has set the instrument to remote with lockout state The LOCAL button is lit when in local state Lights to indicate that the VT2412 S 11364 is in local with lockout state or remote with lockout state When pressed the LOCKOUT button causes the instrument primary and secondary bus addresses to be displayed in the RECORD LENGTH and SAMPLES indicators respectively The normal front panel display can be restored by pressing any other button except ON OFF or LOCAL This button is also used for special front panel operations See Instrument Settings later in this section for more information 13 RECORD LENGTH RECORD LENGTH m Es POUT LocaTON Sa INTERVAL Fi PERIOD e O MULTIPLIER SET EPLAY a PRETRIGGER POST TRIGGER 15 16 17 FIGURE 2 2 FRONT PANEL TIME BASE CONTROLS When pressed the length of the record s for the selected time base can be set with the DECREMENT INCREMENT buttons The RECORD LENGTH button lights when selected The display shows the length of the record s for the currently selected time base 18 VT2412 S 11364 Operation www vxitech com 14 NO OF RECORDS 15 SET 16 DISPLAY 17 CLEAR 18 SAMPLE INTERVAL 19 PRE TRIGGER
56. e TDAC command loads the Trigger DAC value This command is used in the calibration of the VT2412 S 11364 Examples Command Quer Response Description VT2412 S 11364 Command Dictionary 111 VXI Technology Inc TMBS Purpose Specify the time base to be programmed or queried by the subsequent time base commands Type Set or Query Command Syntax TMBS lt channel gt OIE lt channel gt A B Power Up State A Query Syntax TMBS Query Parameters N A Query Response TMBS A TMBS B Description The TMBS command selects the time base to be programmed by subsequent time base commands The front panel displays the current state of the time base selected Examples Command Quer Response Description Select Channel B TMBS B Returns that Channel B is selected 112 VT2412 S 11364 Command Dictionary www vxitech com VSL lt gt Purpose Returns the vertical scale factors for the lt gt channel of the left amplifier Type Query only Command Syntax N A ON N A Power Up State N A Query Syntax VSR lt gt Query Parameters lt gt 1 2 Query Response See below Description The Vertical Scale factors query returns the scale factors for the LEFT amplifier Channel A Examples Command Quer Response Description VSL1 500 e0 3 V CAL VSL2 NONE Selecting lt 2 gt as the parameter will report back NONE if
57. e new breakpoint using the previous steps 50E 9 50E 9 1E 6 SAMPLING A l l INTERVAL 166 1E CHANNEL A 0 856 944 1800 2048 1976 FIGURE 2 8 BREAKPOINT EXAMPLE MEMORY PARTITIONS 40 VT2412 S 11364 Operation www vxitech com 14 When the settings have be set as desired press ARM A and ARM B simultaneously The instrument checks the validity of the settings and reports any warning or error messages which are retrievable over the interface bus 15 Once a trigger occurs the instrument begins acquiring data in both channels If either of the channels do not trigger check the trigger settings and re ARM both channels The display on the XYZ monitor should be similar to Figure 2 9 for Channel A It may not appear the same for Channel B if the rise and fall of the square wave do not fall within the narrow segments that are sampled at 50 ns By carefully readjusting the generator frequency or moving the breakpoints and repeatedly arming Channel B there should be a point at which the rise and fall are within these windows and the display is similar to Figure 2 9 In practice a computer can acquire the waveform and calculate the exact breakpoint locations and sampling intervals for best results CHANNEL A ener CECE EE Eo To S FIGURE 2 9 BREAKPOINT EXAMPLE XYZ DISPLAY When the leading and trailing edges of the pulses are expanded with breakpoints an accurate measurement of rise and fall time
58. e segment boundaries are marked by breakpoints which can be located at any integer multiple of eight samples from sixteen to eight less than the record length Breakpoint locations and sampling intervals are the same for all records within one channel Pre and post triggering modes are provided to allow acquisition of samples both before and after the trigger event ANALOG SIGNALS The analog input signals from the amplifiers are coupled to the instrument through the amplifier interface The amplifier interface also carries the analog trigger signals to generate triggers Signals can be selected from the amplifiers or the rear panel connectors to generate digital trigger signals for the time bases 12 VT2412 S 11364 Introduction www vxitech com INSTRUMENT CONTROL The microprocessor system is the instrument master controller It accepts and decodes commands from the front panel or the interface bus and sets the instrument operating parameters It also controls the interface to the programmable amplifiers In Local state the microprocessor monitors the front panel buttons and controls the display When a parameter is modified with the DECREMENT INCREMENT buttons the microprocessor cycles through only those values that are valid for the current state of the instrument In Remote state commands are accepted from the interface bus The front panel remains operational but front panel inputs that would modify the state of the instrument
59. e that the protective ground circuit is not interrupted A poor or missing circuit can allow the chassis to float to hazardous potentials Ensure that the power cord plug and outlet provide a secure are undamaged and provide a secure path to earth ground Press the ON OFF button or apply a TTL active low on the ACTUATE connector The ON OFF button should light and the fan should start The insturment performs a self test at power up that requires about seven seconds to complete If the test fails the microprocessor generates an error message that is retrievable over the interface bus When the test is complete the front panel indicators and buttons come up in their default states The Acquisition Program An acquisition sequence or program stored in the VT2412 S 11364 for each time base controls data acquisition These programs consist of the number of records length of record s breakpoint locations sampling intervals and trigger parameters for each channel At power up the settings for both time bases are NO OF RECORDS 1 RECORD LENGTH 2048 BREAK POINT LOCATION 0 SAMPLE INTERVAL 5 ns TRIGGER MODE Pre Trigger 0 samples The default acquisition program can be modified from the front panel in local state or over the interface bus in remote state At power up the PROGRAM CHANNEL A button lights to indicate that any changes in the time base parameters will affect the A time base Pressing CHANNEL B causes subsequent
60. ecord length were deleted VT2412 S 11364 Programming 59 VXI Technology Inc TABLE 3 3 EXECUTION WARNING MESSAGES RUE DESCRIPTION 521 Numeric argument is set to next lower number divisible by eight 522 Sample interval or external clock period multiplier is rest to first valid lower value 523 Breakpoint not found in CBPT command 524 BTA is on and only time base A is armed 525 BTA is on and only time base B is armed 526 lt NR1 gt number is greater than 65535 the value is truncated 527 Attempt to clear breakpoint zero is ignored 528 o to execute a command that changes settings or data memory is ignored in local TABLE 3 4 INTERNAL WARNING MESSAGE MESSAGE NUMBER DESCRIPTION 601 Instrument failed to trigger properly in power up test Error Messages The error messages returned by the ERR query are divided into four groups Command Error messages Execution Error messages Internal Error messages and Power Fail Error messages Table 3 5 through Table 3 8 summarize these messages TABLE 3 5 COMMAND ERROR MESSAGES MESSAGE NUMBER DESCRIPTION 101 Invalid command header 102 Invalid argument string 103 Non numeric argument found where a numeric argument is required 104 Invalid hexadecimal argument 105 Missing argument VT2412 S 11364 Programming www vxitech com TABLE 3 6 EXECUTION ERROR MESSAGES REEL DESCRIPTION 20
61. eipt date of the product at customer s facility The sole and exclusive remedy for breach of any warranty concerning these goods shall be repair or replacement of defective parts or a refund of the purchase price to be determined at the option of VTI For warranty service or repair this product must be returned to a VXI Technology authorized service center The product shall be shipped prepaid to VTI and VTI shall prepay all returns of the product to the buyer However the buyer shall pay all shipping charges duties and taxes for products returned to VTI from another country VTI warrants that its software and firmware designated by VTI for use with a product will execute its programming when properly installed on that product VTI does not however warrant that the operation of the product or software or firmware will be uninterrupted or error free LIMITATION OF WARRANTY The warranty shall not apply to defects resulting from improper or inadequate maintenance by the buyer buyer supplied products or interfacing unauthorized modification or misuse operation outside the environmental specifications for the product or improper site preparation or maintenance VXI Technology Inc shall not be liable for injury to property other than the goods themselves Other than the limited warranty stated above VXI Technology Inc makes no other warranties express or implied with respect to the quality of product beyond the description of the goods
62. el to trigger on the negative slope of the waveform The button lights when selected Selects the AC or DC coupling of the triggering signal The AC DC button lights when AC is selected When selected trigger signal frequencies above approximately 50 kHz are attenuated The HF REJ button lights when selected VT2412 S 11364 Operation 21 VXI Technology Inc Programmable Amplifier Functions 35 36 37 l POSITION VARIABLE gt UNCAL O 38 BANDWIDTH FULL O 20 MHz NORM o nv 39 POLARITY 250V PEAK 0 5W MAX 20 pF 31 2 o 34 FIGURE 2 4 FRONT PANEL AMPLIFIER CONTROLS 31 INPUT Two BNC input connectors are provided to aid in switching between Connectors two inputs such as a signal source and a calibration source The A or B input is selected by the button switch adjacent to the connectors item 32 32 A B Switch Selects either the A or B input connector When unlit the A input is selected when lit the B input is selected 33 1 MQ 50 Q Selects an amplifier input impedance of 1 MQ or 50 Q When unlit Switch 1 MQ is selected when lit 50 Q is selected 22 VT2412 S 11364 Operation www vxitech com 34 35 36 37 38 39 40 AC GND DC Switches POSITION Control VARIABLE Control UNCAL BANDWIDTH Switch POLARITY Switch VOLTS DIV Switches These three switches select one of the following input coupling modes AC The AC compo
63. er and issues a warning message Up to 14 breakpoints may be specified in one SBPT command as long as one of the parameter pairs defines the sampling interval for the fixed breakpoint at location zero The total number of breakpoints cannot exceed 14 including the fixed one at location zero If a specified breakpoint already exists the sampling interval is applied to the existing segment Examples Command Query Response Description SBPT 16 1E 6 Sets the breakpoint location to 16 and the samples intervals to 1e 6 SPBT SBPT 16 1e 6 104 VT2412 S 11364 Command Dictionary www vxitech com SET Purpose Returns all settings Type Query only Command Syntax N A AO N A Power Up State N A Query Syntax SET Query Parameters N A Query Response see below Description The SET query returns the status of all programmable instrument functions The query response shown in the example is for the default settings The actual response to the query depends on the instrument settings but the order of the settings returned does not change The message may be longer if more breakpoints are set Notice that the settings for Channel A are reported first followed by the settings for Channel B The command header SET sent with all other query responses is omitted in this case The string can be stored and directly transmitted back to the instrument without modification to restore the le
64. esnseerennseetnn 27 132 VT2412 S 11364 Index
65. estriction is that the pre trigger hold off for Channel B must be satisfied before B will become triggerable OFF Disables the B Triggerable after A mode Both channels trigger independently Examples Command Query Response Description Enables the B Triggerable after A mode BTA OFF Verifies that the B Triggerable after A mode is enabled 72 VT2412 S 11364 Command Dictionary www vxitech com CAL STORE Purpose Commit changes to nonvolatile memory Type Event Command Syntax CAL STORE COI N A Power Up State N A Query Syntax N A Query Parameters N A Query Response N A Description The Calibration Store command saves current settings into nonvolatile memory If the instrument power is cycled these stored settings will be recalled The Calibration Security State must first be disabled before this command will function Examples Command Quer Response Description CAL STORE Saves current setting to nonvolatile memory VT2412 S 11364 Command Dictionary 73 VXI Technology Inc CBPT Purpose Clears all breakpoints or the specified breakpoints Type Set only Command Syntax CBPT lt N8 gt lt N8 gt NIGRA lt N8 gt an unsigned integer multiple of eight Power Up State N A Query Syntax N A Query Parameters N A Query Response N A Description The Clear BreakPoinT co
66. eter lt semicolon gt Message unit command 52 VT2412 S 11364 Programming www vxitech com NUMBERS Numbers are assumed to be ASCII coded decimal digits except for waveform data Three kinds of numbers are used Representation Description lt NR1 gt Signed or unsigned integers including 0 lt NR2 gt Signed or unsigned numbers with a decimal point lt NR3 gt Signed scientific notation lt N8 gt Unsigned integer multiples of 8 Numbers in NR1 notation are signed or unsigned integers for positive integers the plus sign is optional Examples are 127 64 2048 Numbers in NR2 notation are signed or unsigned numbers with a decimal point The NR2 representation of the value zero must not contain a minus sign Examples are 0 123 6 42 0 000 Numbers in NR3 notation are floating point numbers expressed in scientific notation Examples are 1 37e 3 for 1 37 x 10 1 0 4 for 1 x 10 lt space gt 0 e 0 for 0 Numbers in N8 notation are integer multiples of eight without a sign Examples are 16 64 2048 VT2412 S 11364 Programming 53 VXI Technology Inc WAVEFORM DATA I O Waveform data is output in binary rather than ASCII This enables greater throughput in that data is moved in fewer bytes so data transfers require less bus time Waveform data is sent in response to a READ REP or ALT command sent in binary block s of the following format lt BYTE COUNT gt lt DATA BYTES gt lt
67. formation Sampling at a high enough rate to provide good time resolution during the rising edge of the pulse produces a large amount of unnecessary data during the slower parts of the waveform e g the flat top of a pulse The VT2412 S 11364 provides a simple means of changing the sampling interval during an acquisition to expand the important part s of a waveform while recording the remainder at a slower sampling interval For example if the rise time and width of a square wave pulse is to be measured the fast rising edge could be sampled at a 50 ns rate When the pulse reached maximum amplitude the sampling interval might be increased to 1 us to acquire the slower part of the waveform A sampling interval change is marked by a breakpoint set with the front panel BREAKPOINT function in local state or with the SBPT Set BreakPoinT command in remote state Three front panel buttons are provided to set display or clear breakpoints Breakpoints can be set at any integer multiple of eight samples from sixteen to eight less than the record length Remember that all records are identical so breakpoints apply to all records in the selected channel Breakpoints divide the records into segments A segment contains all the samples from the specified breakpoint to the next breakpoint or the end of the record One breakpoint at sample zero defines the first segment segment 0 This breakpoint is always present and cannot be cleared The followi
68. ghest priority to resolve the conflict In the case of setting the record length to 2048 the number of records is set to one Press ARM A The instrument checks the validity of the settings and if errors are found a warning or error message is generated that is retrievable over the interface bus Otherwise the channel becomes triggerable On the next valid trigger the instrument acquires the first 512 point record at 1 us sampling interval Then it waits for another trigger When the next trigger occurs it acquires a second 512 point record and so on until all four records are acquired The XYZ monitor will display four identical waveforms as shown in Figure 2 7 Notice that all waveforms start at the same trigger point All four records are displayed successively on one line starting with record zero If the display is clipped on the top or bottom of the waveform adjust the amplifier POSITION control or decrease the output amplitude of the generator as required Press ARM to acquire and display the new data Repeat this step until the display is similar to Figure 2 7 Ph VN ah SS Sea MAA eel gall a ee ate OA PEs Se FIGURE 2 7 XYZ DISPLAY FOUR 512 POINT RECORDS 1 5 kHz 38 VT2412 S 11364 Operation www vxitech com Setting Breakpoints In many situations a small part of a waveform is of particular interest e g the rising edge of a fast pulse but the remainder of the waveform also contains useful in
69. gnored before data storage begins These samples serve only as a delay timer they do not occupy space in data memory Figure 2 11 illustrates a waveform acquired with post trigger mode Post trigger can only be implemented when the number of records is set to one The range of valid values is from eight to the record length All post trigger data is acquired at the sample interval of the first segment TRIGGER POINT POST TRIGGER gt ONE RECORD gt SAMPLES FIGURE 2 11 POST TRIGGER ILLUSTRATION VT2412 S 11364 Operation 43 VXI Technology Inc Follow these steps to set up post trigger mode 1 Before selecting post trigger mode be sure that the number of records is set to 1 2 Press POST TRIGGER and DECREMENT INCREMENT the value in the SAMPLES display to the desired value The value cannot be incremented beyond the record length 3 ARM the selected time base The instrument begins storing data after it is triggered and the programmed number of samples has been taken The effects of pre and post trigger modes can be illustrated by feeding identical signals to the vertical inputs of both channels and programming the time bases with identical settings use the COPY function Next set time base A to pre trigger mode with 0 samples and time base B to pre trigger mode with 128 samples ARM both time bases and compare the XYZ displays The Channel B data will begin 128 samples before Channel A as
70. h com ID VXI Purpose Type Command Syntax Command Parameters Power Up State Query Syntax Query Parameters Query Response Description Examples Query the VXI identification string Query N A N A N A ID VXI N A VXI ID string The ID VXI query reports the VXI identification string Command Quer Response Description ID VXI ID VXI VM2412S Plugin A V1 07 VT2412 S 11364 Command Dictionary 121 VXI Technology Inc INP Purpose Selects the input connector Type Set or Query Command Syntax INP lt connector gt CONEA lt connector gt A B Power Up State A Query Syntax INP Query Parameters N A Query Response INP A INP B Description The INPut command selects either the A or B input connectors on an amplifier Examples Command Quer Response Description Selects input connector B INP B Verifies that input connector B is selected 122 VT2412 S 11364 Command Dictionary www vxitech com POL Purpose Selects amplifier polarity Type Set or Query Command Syntax POL lt polarity gt AO lt polarity gt NOR INV Power Up State NOR Query Syntax POL Query Parameters N A Query Response POL NOR POL INV Description The POLarity command sets the amplifier mode to normal or inverted polarity In normal mode an increasing voltage cau
71. his is the last multiple of eight that is less than the current record length of 2048 9 Next set the sample interval for the segment defined previously by pressing SAMPLE INTERVAL Set the value to 50 ns 50E 9 using the DECREMENT INCREMENT buttons 10 Set another BREAKPOINT LOCATION to 944 Set the SAMPLE INTERVAL for this segment to 1 us 11 Set another BREAKPOINT LOCATION to 1800 Set the SAMPLE INTERVAL for this segment to 50 ns 12 Set one last BREAKPOINT LOCATION to 1976 Set the SAMPLE INTERVAL for this last segment to 1 us 13 Before arming the instrument check the breakpoint locations and sampling intervals with the DISPLAY BREAKPOINT function a Press DISPLAY The last breakpoint set and its associated sampling interval will be displayed in the BREAKPOINT LOCATION and SAMPLE INTERVAL displays respectively b Press the lt key once to display the next lower breakpoint and sample interval By pressing lt repeatedly each breakpoint location sample interval will be displayed one by one until the lowest breakpoint at location zero is displayed along with the sampling interval for the first segment See Figure 2 8 for an illustration of the memory partitions set in the previous steps c To change one of the breakpoints DISPLAY the location to be changed and press CLEAR The breakpoint is cleared and the sample interval from the preceding breakpoint is applied to all samples up to the next breakpoint Then set th
72. ich the trigger occurs is set by the LEVEL parameter The TRIGGER LEVEL parameter sets the amplitude level on the trigger signal at which the trigger occurs The level ranges from 127 to 128 corresponding to the 8 bit resolution of the instrument 256 discrete levels A setting of 127 means that the trigger will not occur until the signal reaches full scale amplitude A setting of 0 means that the trigger occurs when the signal crosses through zero If the SLOPE is set to the time base triggers when the trigger signal passes through the selected level on the positive slope of the signal If SLOPE is set to the time base triggers at the selected level on the negative slope of the signal 36 VT2412 S 11364 Operation www vxitech com Setting up a Simple Acquisition Program The following is a simple acquisition program to acquire 512 point records of a sine wave in Channel A For a repetitive input signal such as a sine wave all records will be identical they start at the same trigger point 1 2 Power up the VT2412 S 11364 Set the amplifier s VOLT DIV to 0 5 V division Connect a sine wave generator to the Channel A amplifier input and adjust the generator controls for approximately 4 Vp p peak to peak output amplitude at 1 5 kHz Press CHANNEL A to program time base A CHANNEL B could also be used this is just for an example Press RECORD LENGTH The button lights to indicate that the function has
73. interfaces to a IEEE 488 bus system there are a few special considerations for local operation The following are some guidelines for operating under these circumstances The VT2412 S 11364 goes to local state automatically at power up All local operating controls are active and the LOCAL button lights A bus interface controller can then set the instrument to remote state In remote state font panel controls that do not affect the state of the instrument or data memory are still enabled For example DISPLAY BREAKPOINT functions in local or remote state but the ARM buttons are disabled in remote state The ON OFF LOCAL and REMOTE buttons are active and the REMOTE button lights Local control can be restored by pressing LOCAL To prevent local control the bus controller can set the VT2412 S 11364 to remote with lockout state The instrument operates exactly as it does in remote state except that pressing LOCAL does not restore local control In this state the REMOTE and LOCKOUT buttons light The instrument may also be set to local with lockout state The instrument responds the same as in local state The LOCAL and LOCKOUT buttons light When the VT2412 S 11364 returns from remote to local control the instrument performs a validity check of the current settings and reports any errors on the front panel This validity check is identical to the one performed when a time base is armed Therefore when returning from remote to local state ens
74. ired in record one of Channel A as soon as the acquisition is complete and it is addressed to talk When the transmission is complete it expects to be addressed again to send the response to the second READ command Because the response to the READ command will not fit in the output buffer the instrument remains busy until the data is transmitted In this condition the VT2412 S 11364 asserts NRFD and refuses any further input When the second transmission is complete the TMBS B command is executed VT2412 S 11364 Programming 55 VXI Technology Inc QUERY COMMANDS Unless noted as a set command only all commands can be used as query commands A query is executed in either REMOTE or LOCAL state unlike set commands which can only be executed in REMOTE state A message that contains only a query command requires the following syntax lt query gt lt question mark gt lt parameter gt lt semicolon gt An example is TMBS A message can contain multiple queries just as it can contain multiple set commands The set and query commands can also be used together and be mixed in any order However the instrument must be addressed to talk for the response to each query If instead another set command is sent the response to the remaining query or queries is abandoned The VT2412 S 11364 responds to a query with a message similar to the set command format Unless noted the syntax of the reply is lt command gt lt space gt lt paramete
75. is generated that can be retrieved over the interface bus The second step in the process is also performed only when the time base settings have been modified In this step the settings are loaded from the acquisition program into the time base hardware A typical verify and load process takes approximately 50 ms the time may vary slightly with different time base settings The next step is to initialize the hardware for acquisition which takes approximately 300 us If the time base is set to PRE TRIGGER mode one full record of pre trigger data is acquired before the time base becomes triggerable The time required for this acquisition can be calculated by multiplying the number of samples in the record record length by the sample interval for the first segment All pre trigger samples are acquired at the sampling interval of the first segment This pre trigger acquisition is repeated before each record when multiple records are selected VT2412 S 11364 Operation 33 VXI Technology Inc If POST TRIGGER is selected the pre trigger acquisition step is skipped Otherwise when pre trigger acquisition is complete the time base becomes triggerable The next valid trigger initiates acquisition ARM BUTTON PRESSED OR ARM COMMAND RECEIVED TIME BASE SETTINGS CHANGED INCE LAST ARMED CHECK NEW SETTINGS LOAD NEW SETTINGS INITIALIZE HARDWARE PRE TRIGGER MODE A
76. k rear panel output will not blank over ranged data a high low level is generated to blank the display BLNK 0 OFF The Z Blank rear panel output will not blank over ranged data a low high level is generated to blank the display BLNK 1 ON The Z Blank rear panel output will blank over ranged data a high low level is generated to blank the display BLNK 0 ON The Z Blank rear panel output will blank over ranged data a low high level is generated to blank the display Note Blank this command setting Z Blank Polarity BLANK BIT command setting 1 is for working with newer scopes 0 is for working with older scopes TEK7612 compatible Examples Command Query Response Description BLANK BIT 1 Set the Z blanking polarity to a high low level to blank the display BLANK BIT 0 Verifies that the Z blank polarity is set to generate a high low level VT2412 S 11364 Command Dictionary 71 VXI Technology Inc BTA Purpose Enable or disable B Triggerable after A mode Type Set or Query Command Syntax BTA lt state gt AO lt state gt ON OFF Power Up State OFF Query Syntax BTA Query Parameters N A Query Response BTA ON BTA OFF Description The BTA command turns B Triggerable after A mode ON or OFF ON Sets the instrument to B Triggerable after A mode This mode causes the B time base to become triggerable shortly after the first record of Channel A has been acquired One r
77. l A data is readable 0 X X 0 1 0 Channel B data is readable 0 X X X 1 1 Both channels are readable Bit 3 is set if a waveform readable interrupt is generated by Channel A bit 4 is set when Channel B generates the interrupt 58 VT2412 S 11364 Programming www vxitech com WARNING AND ERROR MESSAGES Warning Messages The first 18 warning messages describe errors that occur as the result of conflicting settings e g breakpoints set beyond the record length These warnings indicate unique combinations of four possible conditions The combinations and associated warning messages are shown in Table 3 2 The eight remaining execution warning messages are summarized in Table 3 3 and the internal warning messages are listed in Table 3 4 TABLE 3 2 EXECUTION WARNING MESSAGES o CH ONNEL PRE TRIG POSTTRIG NOofREC BRK PTS A B 501 511 0 0 0 1 502 512 0 0 1 0 503 513 0 0 1 1 504 514 0 1 0 0 505 515 0 1 0 1 506 516 0 1 1 0 507 517 0 1 1 1 508 518 1 0 0 0 509 519 1 0 0 1 PRE TRIG 1 Indicates that the number of pre trigger samples has been set to 16 less that the length of the first segment POST TRIG 1 Indicates that the number of post trigger samples has been set to the record length NO of REC 1 Indicates that the number of records has been set to one because the channel is in post trigger mode BRK PTS 1 Indicates that all breakpoints greater than or equal to the r
78. lationship between the trigger and the acquired signal The external source can be used where the input signal is unusually small in amplitude noisy or for some reason does not provide adequate triggering The external trigger signal is applied to the rear panel LEFT or RIGHT TRIG INPUT connectors These connectors may be looped through from the front panel with a short 50 Q coax cable from the TRIG connectors to the number 3 and 4 connectors on the rear panel This allows the external trigger to be applied to the corresponding front panel connectors The COUPLING button selects AC or DC coupling of the trigger signal When AC coupling is selected the power up default any DC level on the signal is ignored and frequencies below approximately 30 Hz are attenuated In general AC coupling can be used for most applications However if the sweep is to be triggered on a low frequency signal or DC level DC coupling may provide better triggering DC coupling provides more stable triggering on low frequency signal Remember that the amplifier POSITION control affects the level with DC coupling When HF REJ High Frequency REJect is on button lit trigger signal frequencies above approximately 50 kHz are attenuated This provides a means of filtering complex or noisy signals to provide more stable triggering The SLOPE functions determines whether the trigger occurs on the positive or negative slope of the trigger signal The exact level at wh
79. le factors from 10 mV div to 5 V div in nine steps with a 1 2 5 sequence The button indicator that is currently lit indicates the selected scale factor VT2412 S 11364 Operation 23 VXI Technology Inc INSTRUMENT SETTINGS The following shows detailed steps for some of the instrument setups such as addressing gain and product identification from the front panel Set GPIB Primary Address This sets the lower five bits of the GPIB primary address The following sequence sets both My Talk Address MTA and My Listen Address MLA Step 1 From the front panel press the LOCKOUT key This results in displaying the Primary address in the Record Length LED display field and the Secondary address in the Samples LED display field Step 2 Press the LOCKOUT key 4 more times in a row Step 3 Press the Record Length key This will cause the Primary Address to flash indicating that it is ready to be edited Step 4 Decrement or increment the Primary Address by using the arrow keys lt lt lt gt gt gt until the desired address appears in the Record Length display window Step 5 Save the address by pressing the LOCAL key just to the left of the LOCKOUT key This results in saving the Primary Address to nonvolatile memory and restoring the VT2412 S 11364 to normal operation 24 VT2412 S 11364 Operation www vxitech com Set GPIB Secondary Addresses This sets the lower five bits of My Secondary Address MSA f
80. mand Dictionary 127 VXI Technology Inc VAR Purpose Enable or disable variable amplifier gain Type Set or Query Command Syntax VAR lt mode gt AO lt mode gt ON OFF Power Up State OFF Query Syntax VAR Query Parameters N A Query Response VAR ON VAR OFF Description The VAR command enables or disables the variable amplifier gain OFF The amplifier deflection factors ranges are calibrated ON The amplifier deflection factor is controlled by the range and the front panel VARIABLE control In this mode the amplifier is not calibrated but can be continuously adjusted across all ranges Examples Command Quer Response Description Enables variable gain Verifies that variable gain is enabled 128 VT2412 S 11364 Command Dictionary www vxitech com v D Purpose Set the volts per division range Type Set or Query Command Syntax V D lt range gt ANI lt range gt 0 01 0 02 0 05 0 1 0 2 0 5 1 0 2 0 5 0 Power Up State 5 Query Syntax V D Query Parameters N A Query Response V D 0 01 V D 0 02 V D 0 05 V D 0 1 V D 0 2 V D 0 5 V D 1 V D 2 V D 5 Description The Volts Division command sets the calibrated deflection factors ranges from 10 mV per division to 5 V per division in a 1 2 5 sequence Examples Command Quer Response Description Sets the range to 1 V per division V
81. mmand allows the user to delete one or more breakpoints from all records in the selected channel A specific breakpoint or breakpoints can be deleted by specifying the breakpoint location s in the command parameters If no parameters are specified all breakpoints except the fixed one at location zero are deleted When a breakpoint is deleted the sampling interval for the segment preceding the breakpoint is applied to all samples from the preceding breakpoint to the next breakpoint If all breakpoints are deleted the sampling interval for the first segment is applied to the entire record If an invalid breakpoint value is specified a warning message is issued the invalid breakpoint is ignored and all valid breakpoints are deleted Examples Command Quer Response Description CBPT 520 256 Deletes the breakpoints at 256 and 520 CBPT Deletes all breakpoints 74 VT2412 S 11364 Command Dictionary www vxitech com CLK Purpose Select internal or external clock for both time bases Type Set or Query Command Syntax CLK lt source gt OIEA lt source gt INT EXT Power Up State INT Query Syntax CLK Query Parameters N A Query Response CLK INT CLK EXT Description The CLocK command selects the internal or external clock signal as the source for both time bases INT Selects the internal 200 MHz clock signal to drive both time bases Sample intervals specified in the
82. n integer multiple of eight from eight to the record length In post trigger mode only one record may be selected If more than one record is set up an execution warning message is issued and the number of records is set to one when the instrument is armed Post trigger samples are acquired at the sampling interval for the first segment When the time base is triggered the programmed number of samples is ignored before the instrument begins storing data Examples Command Query Response Description MODE PRE 56 Set to acquire 56 samples of pre trigger data MODE MODE PRE 56 Verifies that MODE is set to acquire 56 pre trigger samples VT2412 S 11364 Command Dictionary 93 VXI Technology Inc MTRIG Purpose Generates triggers for both channels Type Set only Command Syntax MTRIG ONIS N A Power Up State N A Query Syntax N A Query Parameters N A Query Response N A Description The Manual TRIGger command causes the armed time bases to trigger by running the trigger level through its range 127 to 128 If the input signal is out of this range off the target the time base does not trigger The MTRIG command has no parameters and is not executed in LOCAL state If the time base s are not armed and triggerable when the MTRIG is received the command is ignored Examples Command Quer Response Description MTRIG Generates a trigger for both channels 94 VT2412 S
83. nary www vxitech com HFR Purpose Enable or disable high frequency reject trigger Type Set or Query Command Syntax HFR lt state gt CONAN lt state gt ON OFF Power Up State OFF Query Syntax HFR Query Parameters N A Query Response HFR ON HFR OFF Description When the HFR parameter is ON frequencies above about 50 kHz are attenuated in the trigger signal This filters complex or noisy signals to provide more stable triggering Examples Command Query Response Description Enables high frequency reject trigger HFR ON Verifies high frequency reject trigger is enabled VT2412 S 11364 Command Dictionary 87 VXI Technology Inc HSF lt CH gt Purpose Returns the horizontal scale factors for lt channel gt Type Query only Command Syntax N A AO N A Power Up State N A Query Syntax HSF lt CH gt Query Parameters lt CH gt A B Query Response See below Description The HSF query returns the horizontal scale factors for the selected channel The scale factors information includes the number and length of records number of breakpoints breakpoint locations sampling intervals and trigger mode The query response is in ASCII The length of the message returned depends on the number of breakpoints set Examples REC 1 2048 NBPT 1 SBPT 0 5e 9 MODE PRE 0 Returns horizontal scale factors for Channel A as follows
84. nd be completely lost in the digitized data Decreasing the sampling interval slightly increasing the sampling frequency may cause one or two samples to be taken during the spike but to accurately determine its amplitude and width may require many samples a very short sampling interval If the spike is consistent a breakpoint can be set to shorten the sampling interval for the duration of the pulse 1 127 VOLTS o N h cb e o 1 127 0 TIME 10us 0 TIME SAMPLES 2048 ANALOG INPUT SIGNAL DIGITIZED OUTPUT DATA FIGURE 2 14 ANALOG SIGNAL INPUT W DIGITIZED DATA OUTPUT Another less obvious problem caused by sampling at too slow a rate is called aliasing Figure 2 16 illustrates a simple case of aliasing The input signal is a 20 kHz sine wave Part b of the figure shows the digitized data that results from sampling the sine wave at 200 ns intervals At this rate there are approximately 250 samples per cycle of the input signal This is more than enough data to accurately reconstruct the input signal If the sampling interval is increased to exactly match the period of the input waveform 50 us the output data represents a flat line since all the samples would be taken at the same point on the sine wave In practice it is very difficult to match the period and phase of the input signal Part e of the figure shows the case where the sampling interval is slightly longer than the period of the input waveform Here the
85. nds to eight divisions as specified for the vertical amplifier For example a 4 V input signal produces full scale deflection when the amplifier is set for 0 5 Volts Division The XYZ monitor screen displays the data for both channels by displaying Channel A data in the top half of the screen and Channel B in the bottom half Therefore the display amplitude is one half of the normal amplitude For example a six division signal produces a three division display on the monitor VT2412 S 11364 Operation 49 VXI Technology Inc Input signals that are beyond the full scale range of the instrument cause the data byte stored in waveform memory to be set to all 1 s for positive over range and all 0 s for negative over range These bytes are blanked on the XYZ monitor Therefore parts of the input waveform that are positioned off the target area appear to be missing on the XYZ display see Figure 2 17 The Blank Bit internal jumper can be set to display over range data at the positive and negative limits of the XYZ display range In this mode over range data appears to be clipped on the display The data stored in the VT2412 S 11364 data memory is not affected PANTANO CHANNEL A A NO Ea CHANNEL B AAN el COSES FIGURE 2 17 OUTPUT DATA CLIPPING 50 VT2412 S 11364 Operation www vxitech com SECTION 3 PROGRAMMING INTRODUCTION The VT2412 S 11364 conforms to the JEEE Standard 488 1978 for general purpose
86. ned as part of the description of the commands used to program the VT2412 S 11364 and its response to interface control messages VT2412 S 11364 Programming 51 VXI Technology Inc TABLE 3 1 VT2412 S 11364 INTERFACE FUNCTIONS FUNCTION SUBSET CAPABILITY Complete Instrument allows minimum settling time on the DIO data line before asserting DAV T in Source handshake SH1 the SH state diagram in the standard gt 1100 ns for the first byte after ATN is released and gt 500 ns for the remaining bytes in a message Acceptor handshake AHI Complete Complete except instrument cannot be set to talk Extended talker TE6 only mode locally includes response to serial poll requires secondary address Complete except instrument cannot be set to listen Eee listener ek only mode locally requires secondary address Service request SRI Complete Remote local RL1 Complete Parallel poll PPO No response to parallel poll Device clear DC1 Complete Device trigger DTO No device trigger capability Controller CO None COMMAND SYNTAX The following format symbols are used lt gt indicates a parameter or defined element 1 indicates the element or group of elements is optional and may be omitted follows an element or group of elements that may be repeated The following delimiters are used to punctuate VT2412 S 11364 commands Delimiter Follows lt space gt Command lt comma gt Param
87. nel 3 CHANNELB Selects the B channel to be programmed by subsequent time base and trigger function entries Also causes the current settings for Channel B to be displayed on the front panel VT2412 S 11364 Operation www vxitech com COPY ARMA ARM B B TRIG AFTERA CLK DECREMENT INCREMENT Copies the settings from the selected time base to the other time base For example if time base A is selected CHANNEL A button lit pressing the COPY button will copy all settings from time base A to time base B Arms the A time base If any changes were made to the A time base settings since the last ARM operation the validity of the settings is first verified If any errors are found during verification a warning message is generated that is retrievable over the interface bus When the ARM operation is complete the time base becomes triggerable Arms the B time base If any changes were made to the B time base settings since the last ARM operation the validity of the settings is first verified If any errors are found during verification a warning message is generated that is retrievable over the interface bus When the ARM operation is complete the time base becomes triggerable Set the VT2412 S 11364 to B TRIGgerable AFTER A mode In this mode time base B becomes triggerable after the first record of A is acquired If only time base B is armed it will not trigger until A is armed and has acquired one record of data
88. nent of the signal is coupled to the input while the DC component is blocked GND The input connectors are disconnected from the amplifier input and the amplifier input is connected to ground DC Both the AC and DC components of the signal are coupled to the amplifier input The button that is currently lit indicates the selected input coupling mode Controls the vertical position of the trace by injecting a DC offset into the amplifier along with the input signal Provides continuously variable scale factors between calibrated ranges The variable scale factors overlap and are uncalibrated When the VT2412 S 11364 is set to Local mode this control is operative only when the UNCAL button is lit Item 37 When the VT2412 S 11364 is in Remote mode the VARIABLE control is inoperable regardless of the UNCAL function setting unless enabled under program control Its control setting is not programmable When changing from Local to Remote mode the VARIABLE control is automatically set to OFF so that the vertical scale factors are calibrated When pressed and lit selected the VARIABLE control described above is operable Selects full amplifier bandwidth or reduced amplifier bandwidth of 20 MHz When unlit full bandwidth is selected when lit reduced bandwidth is selected Selects normal or inverted amplifier mode When unlit normal mode is selected when lit inverted mode is selected These nine switches select calibrated sca
89. ng example illustrates the use of breakpoints and sample interval switching to measure the rise time or pulse width of a long pulse To reproduce the example a square wave generator with a controlled rise time of approximately 0 1 us is required 1 Connect the square wave generator to the inputs of both amplifiers with a BNC T connector Set the amplifiers VOLT DIV to 0 5 V division and adjust the generator for about 3 Vp p output 2 Set the generator frequency to 600 Hz 3 Press PROGRAM CHANNEL B 4 Press RECORD LENGTH and set the value to 2048 with the DECREMENT INCREMENT buttons 5 Press NO OF RECORDS The number of records changes to one 1 automatically since one 2048 point record fills the waveform memory 6 Set the sampling interval for the first segment to 1 us by pressing the SAMPLE INTERVAL button and incrementing the value to 1E 6 7 Press the COPY button This copies the current settings of Channel B into Channel A The result is a single record of 2048 points in Channel A with no breakpoints and a sampling interval of 1 us This will provide a comparison for the waveform acquired with breakpoints in Channel B VT2412 S 11364 Operation 39 VXI Technology Inc 8 Now set the breakpoints in Channel B Press SET BREAKPOINT Increment the value in the BREAKPOINT LOCATION display to 856 Notice that the display cycles through multiples of eight samples NOTE The value will not increment beyond 2040 since t
90. nt may be individually transmitted The channel A or B record number and segment number are specified parameters If the record and segment parameters are omitted the entire contents of the specified channel are transmitted If included the record number parameter must be an integer value from zero to the number of records less one The first record is designated as record zero 0 For example the command READ A 2 returns the waveform data from the third record in Channel A The third parameter if included defines the segment number to be read If the segment number parameter is included a record number must first be specified Valid segment numbers range from zero to the number of segments less one As with record numbers the segments are numbered starting with zero so the first segment is segment zero 0 If a record or segment number specified in a READ command does not exist an execution error message is issued and the command is ignored When part of the data memory is unused e g 2 records of 256 points are set up only the valid waveform data is transmitted Unused parts of data memory are ignored Examples Command Quer Response Description READ A Reads Channel A READ B 0 3 Reads Channel B record 0 first record segment 3 fourth segment 98 VT2412 S 11364 Command Dictionary www vxitech com REC Purpose Set the number and length of records Type Set or Query
91. number of records 1 length 2048 number of breakpoints 1 location of breakpoint 0 default sampling intervals 5e 9 trigger mode pre trigger 0 samples 88 VT2412 S 11364 Command Dictionary www vxitech com ID Purpose Set instrument ID Type Set or Query Command Syntax ID lt string gt ANI lt string gt up to 49 characters encased in quotation marks Power Up State N A Query Syntax ID Query Parameters N A Query Response Up to 49 characters encased in quotation marks Description The ID command sets the ID model or other information reported by the ID query A CAL STORE command is required to commit any changes to nonvolatile memory The factory default settings are ID VXI VM2412S Mainframe 1 11 mainframe ID VXI VM2412S Plugin A V1 07 Channel A amplifier ID VXI VM2412S Plugin B V1 07 Channel B amplifier Note The default version numbers may be different than listed above Examples Command Quer Response Description ID VXI VM2412S MAINFRAME 1 11 Input the ID string CAL STORE Store the new setting in nonvolatile memory ID ID VXI VM2412S Mainframe 1 11 Verifies the ID string VT2412 S 11364 Command Dictionary 89 ID VXI VXI Technology Inc Query the VXI identification string Query Command Syntax N A Command Parameters N A Power Up State N A
92. od multiplier The PERIOD indicator lights when the internal clock is selected and the value shown in the SAMPLE INTERVAL display is the period in seconds The MULTIPLIER indicator lights when the external clock input is selected and the value in the SAMPLE INTERVAL display is the external clock period multiplier When pressed the number of pre trigger samples to be stored for the selected time base can be set with the DECREMENT INCREMENT buttons The range of values is from zero to sixteen less than the number of samples in the first segment When pressed the DECREMENT INCREMENT buttons set the number of samples that are ignored after the trigger before the instrument begins storing data Allowable post trigger values range from eight to the record length When POST TRIGGER mode is selected only one record may be selected for that channel VT2412 S 11364 Operation 19 Trigger Functions VXI Technology Inc 21 22 23 24 25 a LEFT gt RIGHT 23 o a TRIGGER LEVEL 24 L TRIGGERED R TRIGGERED INT EXT 25 e SOURCE a 26 27 eo SLOPE 28 y K AC DC E 29 0 COUPLING d 30 MAN TRIG HF REJ TRIGGER FUNCTIONS y FIGURE 2 3 FRONT PANEL TRIGGER CONTROLS TRIGGER LEVEL LandR TRIGGERED LEFT RIGHT INT EXT When pressed the trigger level for the currently selected trigger channel can be set by
93. or Internal Error Power Fail Error Execution Warning Internal Warning Device Dependent Status VXI Technology Inc Indicates that the VT2412 S 11364 has received a command that it cannot understand or implement under any circumstances The command does not affect the state of the instrument Indicates that the VT2412 S 11364 has received a command that it understands but cannot implement due to the current state of the instrument The command does not affect the state of the instrument Indicates that an internal hardware failure has occurred Indicates that a power fail is about to happen or that an internal analog supply has failed The instrument remains capable of responding to a serial poll for at least 10ms If a power fail occurs and the power is restored this condition is replaced by the power on condition Indicates that the instrument has found a conflict in the settings and has changed the settings for the specified channel to resolve the conflict This warning may also alert the user to potential problems with a particular setting combination Indicates that the instrument has detected an internal error The instrument remains operational but the source of the problem should be found and corrected as soon as possible Device dependent status is reported only when there is no system status to report Bit 8 7 1 X 1 X 1 X 1 X 6 5 4 3 2 1 0 X 0 0 0 0 Neither channel is readable 0 X 0 X 0 1 Channe
94. or the main frame the Channel A amplifier and the Channel B amplifier The selected number is MSA for the main frame The Channel A amplifier is assigned the mainframe address MSA 1 The Channel B amplifier is assigned the mainframe address MSA 2 Step 1 From the front panel press the LOCKOUT key This results in displaying the Primary address in the Record Length LED display field and the Secondary address in the Samples LED display field Step 2 Press the LOCKOUT key more 4 times in a row Step 3 Press the PRE TRIGGER or POST TRIGGER key same effect This will cause the Secondary Address to flash indicating that it is ready to be edited Step 4 Decrement or increment the flashing number by using the arrow keys lt lt lt gt gt gt until the desired address appears in the Record Length display window Step 5 Save the address by pressing the LOCAL key just to the left of the LOCKOUT key This results in saving the Secondary Address to nonvolatile memory and restoring the VT2412 S 11364 to normal operation VT2412 S 11364 Operation 25 VXI Technology Inc Set Product ID This GPIB command allows the user to change the unit s ID string The defaults are VXI VM2412S Mainframe 1 11 mainframe VXI VM2412S Plugin A V1 07 Channel A amplifier VXI VM24125 Plugin B V1 07 Channel B amplifier Note The default version numbers may be different than listed above ID lt ID string gt where lt ID string gt
95. ored in memory for display on an XYZ monitor Selects 115 VAC or 230 VAC operation CAE 22 three prong power connector IEC coded Provides connection to the interface bus specified in IEEE Standard 488 1978 VT2412 S 11364 Operation 31 VXI Technology Inc OPERATING PROCEDURES Before operating the VT2412 S 11364 ensure the instrument has adequate airflow and nothing is blocking the fan intake screen on rear panel or the air exhaust holes on the sides of the instrument XYZ Display An XYZ monitor connected to the rear panel XYZ outputs provides a convenient method of visually setting up the instrument The VT2412 S 11364 automatically displays the contents of both data memories after each acquisition During acquisition and while the microprocessor is busy executing commands the display refresh is disabled This may cause some normal display flicker during execution of commands No scale factor readout is displayed on the XYZ monitor The XYZ display is divided into two halves The upper half displays the contents of Channel A and the lower half displays Channel B Applying Power The VT2412 S 11364 power cord must be connected to an outlet with a security grounded protective ground contact and the correct single phase voltage For the front panel ON OFF switch or the rear panel ACTUATE connector to power up the instrument the PRINCIPLE POWER SWITCH must be turned on To avoid electrical shock ensur
96. p to fourteen segments with a programmable sampling interval in each one The sampling interval is selectable from 5 ns to 1 s using the internal clock When an external clock is used the period of the applied signal can be multiplied by a selectable multiplier from 1 to 200 x 10 The sample interval is logical where the last sample of a segment is the time origin of the following segment Two separate digital time bases can be individually programmed for memory partitioning sampling interval and triggering functions Because the two channels are independent digitized data can be read from one channel while the other channel is acquiring data VXI Technology 2412 PROGRAMMABLE DIGITIZER FIGURE 1 1 VT2412 S 11364 DUAL CHANNEL PROGRAMMABLE DIGITIZER VT2412 S 11364 Introduction 11 VXI Technology Inc The front panel of the VT2412 S 11364 allows local control of the instrument Operating parameters are set by pressing the appropriate function key and decrementing or incrementing the parameter See Section 2 Operation for more information The parameter cycles through only the values that are valid for the current state of the instrument The instrument checks the settings each time the ARM command is received by means of the front panel or by word serial command Errors are reported over the interface bus Remote control front panel operation and data output through the interface bus are simplified by the
97. panel press the LOCKOUT key This results in displaying the Primary address in the Record Length LED display field and the Secondary address in the Samples LED display field Step 2 Press the LOCKOUT key 4 more times in a row Step 3 Press the BREAKPOINT LOCATION DISPLAY key This will cause the currently selected blanking mode to appear in the 3 left most display fields RECORD LENGTH NO OF RECORDS BREAK POINT LOCATION SAMPLE INTERVAL PERIOD MULTIPLIER SET DISPLAY CLEAR This is the default setting Step 4 Toggle between the 4 possible choices by using the arrow keys lt lt lt gt gt gt Z Blank Polarity Blank BLNK 1 OFF The Z Blank rear panel output will not blank over ranged data a high low level is generated to blank the display BLNK 0 OFF The Z Blank rear panel output will not blank over ranged data a low high level is generated to blank the display BLNK 1 ON The Z Blank rear panel output will blank over ranged data a high low level is generated to blank the display BLNK 0 ON The Z Blank rear panel output will blank over ranged data a low high level is generated to blank the display Note 1 is for working with newer scopes 0 is for working with older scopes TEK7612 compatible Step 5 Save the selection by pressing the LOCAL key just to the left of the LOCKOUT key This results in saving the Blanking Mode selected to nonvolatile memory and restoring the VT2412 S 11364 to no
98. plifier is assigned the mainframe address MSA 2 A CAL STORE command must be sent to store the values into nonvolatile memory Examples Command Query Response Description GPIB 20 0 Sets the primary address to 20 and the secondary address to 0 CAL STORE Store the new setting in nonvolatile memory GPIB 20 0 Verifies that the primary address is set to 20 and the secondary address to 0 VT2412 S 11364 Command Dictionary 85 VXI Technology Inc GPIB TERM Purpose Set terminator type Type Set or Query Command Syntax GPIB TERM lt term_type gt AO lt term_type gt LINEFEED EOI Power Up State N A Query Syntax GPIB TERM Query Parameters N A Query Response GPIB LINEFEED GPIB EOI Description The GPIB TERM command sets the type of terminator message recognized by the instrument The two possible selections are LINEFEED or EOI The LINEFEED setting uses a Line Feed character to signal the end of a message The EOI setting uses the GPIB EOI End or Identify signal to indicate the end of a message Use the CAL STORE command to save this setting into nonvolatile memory Examples Command Quer Response Description GPIB TERM LINEFEED Sets the GPIB termination to LINEFEED CAL STORE Store the new setting in nonvolatile memory GPIB TERM GPIB LINEFEED Verifies that the GPIB termination is set to LINEFEED 86 VT2412 S 11364 Command Dictio
99. put X10 X10 probe is present on the selected input X100 X100 probe is present on the selected input ID Probe is on IDENTIFY Examples Command Quer Response Description X1 Reports that there is no probe connected or a non attenuating probe VT2412 S 11364 Command Dictionary 125 VXI Technology Inc RIN Purpose Selects amplifier input impedance Type Set or Query Command Syntax RIN lt impedance gt OIGAN lt impedance gt HI LOW Power Up State HI Query Syntax RIN Query Parameters N A Query Response RIN HI RIN LOW Description The RIN command selects the amplifier input impedance HI The amplifier is set to 1 MQ input impedance LOW The amplifier is set to 50 Q input impedance Examples Command Quer Response Description RIN LOW Sets the input impedance to 50 Q RIN RIN LOW Verifies that the input impedance is set to 50 Q 126 VT2412 S 11364 Command Dictionary www vxitech com SET Purpose Query the settings of the input amplifier Type Query Command Syntax N A ON N A Power Up State N A Query Syntax SET Query Parameters N A Query Response See below Description The SET query returns the settings of the input amplifier Examples Command Quer Response Description BW FUL CPL DC RIN HI POL NOR INP A These are the default settings of the input amplifier VT2412 S 11364 Com
100. r gt lt semicolon gt For example the query TMBS is answered with when time base A is selected TMBS A 56 VT2412 S 11364 Programming www vxitech com INSTRUMENT STATUS The VT2412 S 11364 reports a status byte when serial polled by the system controller The status byte contains the internal status of the instrument Two main types of status may be reported system status and device status System status indicates conditions that are general Device status indicates conditions that are unique to a single instrument type The status byte read from the VT2412 S 11364 during a serial poll contains the following information Bit N Q A A A N 0 1 Device status 0 System status Service requested 1 Abnormal condition 0 Normal condition Busy Device system status Device system status Device system status Device system status Normal condition system status Bit 8 0 0 Power on condition exists after the instrument is powered on byte is read 7 1 1 6 5 4 3 0 X 0 0 0 X 0 0 Abnormal condition system status Bit 8 0 0 0 0 0 0 7 1 1 6 5 4 3 1 X 0 0 1 X 0 0 1 X 0 0 1 X 0 1 1 X 0 1 1 X 0 1 Power on Remote request This condition exists until the status Command Error Execution Error Internal Error Power Fail Error Execution Warning Internal Error Warning VT2412 S 11364 Programming 57 Command Error Execution Err
101. rmal operation VT2412 S 11364 Operation 27 VXI Technology Inc Set Channel Gain The VT2412 S 11364 allows access to set the gain of the selected channel through the front panel or remotely via GPIB Commands Below is an example of setting the gain through the front panel See the Command Dictionary section for information on remote access Step 1 Step 4 Step 5 From the front panel press the LOCKOUT key This results in displaying the Primary address in the Record Length LED display field and the Secondary address in the Samples LED display field Press the LOCKOUT key 4 more times in a row Press the SAMPLE INTERVAL key This will result in the display of current gain setting for the selected channel Channel A Channel B as follows RECORD LENGTH NO OF RECORDS BREAK POINT LOCATION SAMPLE INTERVAL PERIOD MULTIPLIER SET DISPLAY CLEAR This is the default setting Adjust the gain setting up or down using the following keys with the specified effect lt 0 0001 gt 0 0001 lt lt 0 001 gt gt 0 001 Save the selection by pressing the LOCAL key just to the left of the LOCKOUT key This results in saving the gain setting to nonvolatile memory and restoring the VT2412 S 11364 to normal operation 28 VT2412 S 11364 Operation www vxitech com Set Arm Delay This sets the delay from the receipt of the ARM command until the instrument actually arms
102. s and pulse width can be made in a single acquisition All sampling intervals are derived from the highly stable 200 MHz internal clock and the sample interval switching is coherent the last sample of a segment is the time origin of the following segment Therefore time measurements of long periods can be made with 10 ns resolution worst case VT2412 S 11364 Operation 41 VXI Technology Inc Copy In some cases it may be required to set up the same or similar acquisition programs in both channels of the VT2412 S 11364 The COPY function provides a simple means of copying all the time base settings from one channel to the other When COPY is pressed the settings of the selected channel are copied to the unselected channel All previous settings in the unselected channel are lost For example to copy the settings of Channel A to Channel B first press CHANNEL A to select it Next press COPY Note that the instrument control functions e g CLK B TRIG AFTER A etc are unaffected by the COPY function Pre Trigger Mode It is often necessary to acquire part of a signal that occurs before the trigger event For example the leading edge of a transient pulse may be used to trigger an acquisition To capture the full leading edge some samples must be stored just before the trigger occurs The PRE TRIGGER mode causes the VT2412 S 11364 to store a programmed number of samples before the trigger event To visualize the pre trigger
103. s passed while the DC component is blocked DC Both the AC and DC component of the input signal is passed GND The input connectors are disconnected from the amplifier input The amplifier input is connected to ground Examples Command Quer Response Description CPL GND Sets the coupling mode to the GROUND setting CPL CPL GND Verifies that the coupling mode is set to GROUND VT2412 S 11364 Command Dictionary 119 VXI Technology Inc ID Purpose Set instrument ID Type Set or Query Command Syntax ID lt string gt ANI lt string gt up to 49 characters encased in quotation marks Power Up State N A Query Syntax ID Query Parameters N A Query Response up to 49 characters encased in quotation marks Description The ID command sets the ID model or other information reported by the ID query A CAL STORE command is required to commit any changes to nonvolatile memory The factory default settings are ID VXI VM2412S Plugin A V1 07 Channel A amplifier ID VXI VM2412S Plugin B V1 07 Channel B amplifier Note The default version numbers may be different than listed above Examples Command Quer Response Description ID VXI VM2412S PLUGIN A V1 07 Input the ID string CAL STORE Store the new setting in non volatile memory 1D ID VXI VM2412S Plugin A V1 07 Verifies the ID string 120 VT2412 S 11364 Command Dictionary www vxitec
104. ses increasing data values In inverted mode a decreasing voltage causes increasing data values Examples Command Quer Response Description Set the amplifier mode to inverted polarity POL INV Verifies that the amplifier is set to inverted mode VT2412 S 11364 Command Dictionary 123 VXI Technology Inc POS Purpose Controls the vertical position of the trace Type Set or Query Command Syntax POS lt position gt ANI lt position gt 10 22 to 10 24 in 0 02 increments Power Up State 0 Query Syntax POS Query Parameters N A Query Response POS 10 22 to POS 10 24 Description The POSition command controls the vertical position of the trace Increasing values of position increase the data values For example a POS 2 setting corresponds to 2 divisions from center screen Examples Command Quer Response Description Sets the vertical position to 1 POS 1 Verifies that the vertical position is set to 1 124 VT2412 S 11364 Command Dictionary www vxitech com PRB Purpose Query the probe setting on the selected input Type Query Command Syntax N A AO N A Power Up State N A Query Syntax PRB Query Parameters N A Query Response X1 X10 X100 ID Description The PRoBe query returns the probe setting on the selected input X1 No probe or a non attenuating probe is present on the selected in
105. settings of time base A to time base B Copy the settings of time base B to time base A Copy the settings of the left trigger channel to the right trigger channel Copy the settings of the right trigger channel to the left trigger channel The time base functions copied with a COPY AB or COPY BA command are Record length and number of records REC command Breakpoint locations and sample intervals SBPT command Logical trigger channel LTC command Pre Post trigger mode and number of samples MODE command ae O The trigger functions copied with a COPY LR or COPY RL command are Trigger source SRC command Trigger slope SLO command Trigger level LEV command Trigger coupling CPL command High Frequency Reject HFR command AREA Command Query Response Description Copies the settings of time base A to time base B COPY AB COPY LR Copies the trigger settings of the left trigger channel to the right trigger channel 76 VT2412 S 11364 Command Dictionary www vxitech com CPL Purpose Set trigger coupling to AC or DC Type Set or Query Command Syntax CPL lt coupling gt CONAN lt coupling gt AC DC Power Up State AC Query Syntax CPL Query Parameters N A Query Response CPL AC CPL DC Description The CouPLing command selects AC or DC coupling of the trigger signal for the selected trigger channel AC Select AC coupling of the rigger channel
106. shown in Figure 2 12 a ee FEE TN am MEA CHANNEL B FIGURE 2 12 CHANNEL A B PRE TRIGGER EXAMPLE Repeat this procedure setting Channel B for post trigger mode Ensure that both time bases are set for one record The acquired waveform from Channel B will appear delayed by 128 samples from Channel A s data 44 VT2412 S 11364 Operation www vxitech com B Triggerable After A Mode This mode provides a means of inhibiting Channel B trigger until the first record of Channel A is acquired When selected the B time base becomes triggerable after the first record of A is acquired The B channel trigger conditions must be met to actually trigger the time base After the first record both time bases act independently requiring a separate trigger for each record as illustrated in Figure 2 13 TRIGGER BEGINS ACQUISITION CHANNEL A RECORD 0 RECORD 1 RECORD 2 RECORD 3 CHANNEL B CHANNEL B TRIGGER gt RECORD 1 RECORD 2 RECORD 3 INHIBITED TRIGGER BEGINS ACQUISITION FIGURE 2 13 TRIGGERABLE AFTER A ILLUSTRATION If only Channel B is armed with B Triggerable After A mode selected time base B will not accept a trigger until Channel A is armed and has acquired its first complete record If only Channel A is armed it triggers normally but Channel B does not trigger until it is armed External Clock An external sampling ECL level clock applied to the rear panel EXT CLOCK INPUT connector can drive the
107. ter H Note This command is included for 7612D compatibility only it does not actually perform an operation Examples Command Query Response Description EXEC H420 82 VT2412 S 11364 Command Dictionary www vxitech com FET Purpose Fetch Data from the specified address included for 7612D compatibility only always returns a H00 Type Set only Command Syntax FET H lt address gt AN lt address gt hexadecimal address value Power Up State N A Query Syntax N A Query Parameters N A Query Response N A Description The address is specified as a one to four digit hexadecimal number preceded by the letter H The response is returned in ASCII with an H followed by two digits representing the hexadecimal value read from the specified location Note This command is included for 7612D compatibility only it always returns a HO00 Examples Command Query Response Description FET H420 H000 VT2412 S 11364 Command Dictionary 83 VXI Technology Inc GAIN POT Purpose Set channel gain Type Set or Query Command Syntax GAIN POT lt channel gt lt gain_value gt ONE ETE lt channel gt 0 1 0 Channel A 1 Channel B lt gain_value gt floating point number Power Up State N A Query Syntax GAIN POT lt channel gt Query Parameters lt channel gt 0 1 0 Channel A 1 Channel B Q
108. time base entries to modify the program for Channel B 32 VT2412 S 11364 Operation www vxitech com The power up state also lights the SELECT LEFT button to indicate that the left trigger channel is assigned to the current time base time base A at power up The trigger for the time base will be derived from the settings in the left channel Any modifications to the trigger parameters will affect the left trigger channel Pressing SELECT RIGHT will assign the right trigger channel to the currently selected time base and cause subsequent trigger function entries to modify the right trigger channel parameters The left trigger channel gets its internal trigger signal from the left amplifier The right trigger channel gets its internal trigger signal from the right amplifier The power up settings for both trigger channels are SOURCE Internal SLOPE Positive COUPLING AC HF REJ Off LEVEL 0 Arming the Time Base The VT2412 S 11364 time bases must be armed before they can be triggered to start an acquisition The flow chart in Figure 2 6 illustrates the ARM operation If any of the time base settings have been modified since the last arming the first step is to check the validity of the new settings Conflicts such as breakpoints set beyond record length are corrected with record length having the highest priority the record length is never changed to resolve a conflict in the settings If conflicts are found an error message
109. uery Response Floating point number Description The Gain Pot command sets the gain value for the specified channel Use the CAL STORE command to save the new setting to nonvolatile memory The factory default setting is 1 0000 The Security State must first be disabled to change this setting Examples Command Query Response Description GAIN POT 1 0 0000 Sets the gain for Channel A to zero CAL STORE Store the new setting in nonvolatile memory GAIN POT 1 0 0000 Verifies that the gain setting for Channel A is zero 84 VT2412 S 11364 Command Dictionary www vxitech com GPIB Purpose Set the primary and secondary addresses Type Set or Query Command Syntax GPIB lt primary gt lt secondary gt AO lt primary gt numeric value lt secondary gt numeric value Power Up State N A Query Syntax GPIB Query Parameters N A Query Response lt primary gt lt secondary gt Description The GPIB command sets the GPIB primary and secondary addresses The first number sets the lower five bits of the GPIB primary address which represents both My Talk Address MTA and My Listen Address MLA The second number sets the lower five bits of My Secondary Address MSA for the main frame the Channel A amplifier and the Channel B amplifier The selected number is MSA for the main frame The Channel A amplifier is assigned the mainframe address MSA 1 The Channel B am
110. urce slope and coupling parameters Programmable Amplifier Functions There are two separate channels The following sections describe the functions of each of these front panel sets in detail Each section includes a front panel breakout of the function set that shows the location of each item described The entire front panel is shown in Appendix A The connector section on the front panel labeled FROM REAR connectors 1 2 3 and 4 provide straight through connection to the corresponding rear panel connectors See the Rear Panel Connections section for a functional description of these connectors VT2412 S 11364 Operation 15 VXI Technology Inc Instrument Control Functions 2 3 4 e 5 CHANNEL A A ARMA CHANNEL B y ARMB 1 a E e 6 a DECREMENT INCREMENT oN PROGRAM RI lt lt lt gt gt gt COPY AFTER A CORE FTER A Ja p vi 9 o 8 REMOTE LOCAL LOCKOUT CLK f ON OFF INT EXT y INSTRUMENT FUNCTION y 10 11 12 1 FIGURE 2 1 FRONT PANEL INSTRUMENT CONTROLS 1 ON OFF Turns the VT2412 S 11364 power ON or OFF if the rear panel PRINCIPLE POWER SWITCH is ON The rear panel ACTUATE connector overrides the ON OFF switch The ON OFF button illuminates when power is on 2 CHANNELA Selects the A channel to be programmed by subsequent time base and trigger function entries Also causes the current settings for Channel A to be displayed on the front pa
111. ure the settings are valid The instrument returns to local state with the settings left from the remote state No settings are changed unless conflicts are found in the validity check Acquiring Data The VT2412 S 11364 is a waveform digitizing instrument Since it samples the analog input at discrete time intervals the output data is a collection of values that represent the amplitude of the input signal at the sampling points Keeping this in mind and observing a few guidelines when setting up the instrument will ensure that the digitized data accurately represents the analog input signal Selecting a Sampling Interval It is important to remember that the digitized data is simply a string of numbers stored in waveform memory not the actual signal These numbers represent the signal amplitudes at discrete sample points One value is stored for each sample at the sampling rate programmed for the current segment Figure 2 14 shows an input waveform and illustrates the digitized data that results 46 VT2412 S 11364 Operation www vxitech com It is clear that the more samples taken of the input waveform the more accurately the output data represents the analog signal A simple example is the input waveform shown in Figure 2 15 Here the analog input signal is a slowly varying signal with a fast noise spike If the sample interval is considerably longer than the width of the noise spike the spike may occur between two samples a
112. will not be accepted and changes will not be executed Other tasks performed by the microprocessor include acting as an interface for the programmable amplifiers performing a power up test of the instrument monitoring the state of the power supplies and refreshing the XYZ display POWER SUPPLY The VT2412 S 11364 power supply provides regulated voltages for the analog and digital circuitry as well as the amplifiers In addition to the front panel ON OFF switch remote control of the supply is provided through two rear panel connectors The supply can be turned on and off by applying a TTL level signal to the ACTUATE connector The ENABLE output can control the ACTUATE input of another similar instrument UNPACKING THE VT2412 S 11364 When the VT2412 S 11364 is unpacked from its shipping carton the contents should include the following items 1 VT2412 S 11364 Dual Channel Programmable Digitizer 1 VT2412 S 11364 Dual Channel Programmable Digitizer User s Manual this manual 1 Power Cord All components should be immediately inspected for damage upon receipt of the unit VT2412 S 11364 Introduction 13 VXI Technology Inc VT2412 S 11364 GENERAL SPECIFICATIONS GENERAL SPECIFICATIONS DUAL 90 MHZ BANDWIDTH INPUTS 200 MSample s each RESOLUTION 8 bit resolution LINE INPUT 90 to 132 VAC 180 to 250 VAC 48 to 440 Hz Line Input SOFTWARE Software command set compatible with the Tektronix 7
113. y Inc REM Purpose Enable or disable asserting SRQ when REMOTE is pressed Type Set or Query Command Syntax REM lt state gt CONAN lt state gt ON OFF Power Up State OFF Query Syntax REM Query Parameters N A Query Response REM ON REM OFF Description The REMote command controls the response of the instrument when the front panel REMOTE button is pressed ON Assert SRQ when REMOTE button is pressed if the RQS function is set ON power up condition Set the status byte to reflect the remote request status OFF Do not assert SRQ when REMOTE button is pressed but set remote request byte This is the power up condition Examples Command Query Response Description Enables asserting SRO REM ON Verifies asserting SRO is enabled 100 VT2412 S 11364 Command Dictionary www vxitech com REP Purpose Type Command Syntax Command Parameters Power Up State Query Syntax Query Parameters Query Response Description Examples Set Repeat ARM READ sequence for lt channel gt time base n times Set only REP lt NR1 gt lt channel gt lt NR1 gt number of times to repeat lt channel gt A B A B B A N A N A N A N A The REPeat command allows the user to improve throughput when acquiring multiple waveforms by acquiring several waveforms with a minimum of controller interaction The instrument executes ARM an

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