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LDX-3232 Device-Dependent Commands

1. TASer COND 0 Current Limit hs ha opa po 8 7 6 5 4 3 2 1 0 1 Voltage Limit 7 e s 4 s 2 t1 o 0 Operation Complete 2 N A 1 Request Control 3 Power Limit mann Pd 2 Query Error 4 Interlock LOGICAL EI Z 3 Device Dependendent Error amp 5 5 N A u OR izi 4 Execution Error 9 6 Voltage Limit 5 Command Error Ira c 7 Open Circuit 6 User Request OR 7 Power On Out of Tolerance LieisitiSieitio Lt i 4 10 Output On Standard E 11 Ready for Calibration Event Status Enable QUEUE 12 N A Register NOT EMPTY 5 8 7 6 5 4 3 2 1 18 Na ESE A m 14 ESE OUTPUT TASER Condttn Status Enabb 15 NA QUEUE IAS ENABE COND IAS ENABE TASER Event Status Regster Status Byte Register TASer EVEnt 0 Current Limit SERVICE 1 STE 1 Voltage Limit REQUEST di 7 e s 4 s 2 1 o 0 NA fis fia fis fe far po 9 8 7 e s a s a 1 o 2 N A GENERATION l 1 1 3 Power Limit 2 LASER Event td LOGICAL 6 3 LASER Cond m OR E Y D 4 Message Available 6 Comp Voltage Limit Z 4j 5 Event Status Summary 7 Open Circuit 6 Re
2. Error Code Explanation E 001 Memory allocation failure E 103 DEFINITE LENGTH ARBITRARY BLOCK PROGRAM length too long E 104 NON DECIMAL NUMERIC PROGRAM DATA type not defined E 105 DECIMAL PROGRAM DATA exponent not valid E 106 DECIMAL PROGRAM DATA digit expected E 123 Command not found E 124 program mnemonic gt Lookup failed because query command type match failed E 126 Too few or too many program data elements E 201 PROGRAM value out of range E 202 PROGRAM DATA will not convert to valid type 01 10 LDX 3232 101 CHAPTER CALIBRATION AND TROUBLESHOOTING Error Messages Error Code Explanation E 203 Security violation command is not available without clearance E 205 PROGRAM DATA is not a Boolean value or word E 207 PROGRAM DATA will not convert to an unsigned 16 bit value E 209 PROGRAM DATA will not convert to an unsigned 32 bit value E 210 PROGRAM DATA will not convert to a floating point value E 211 PROGRAM DATA will not convert to a character value E 213 PROGRAM DATA is incorrect block data length E 214 PROGRAM DATA length exceeds maximum E 302 Query error device was addressed to talk but GPIB controller failed to read all of the RESPONSE MESSAGE E 501 LASER interlock disabled output E 503 LASER open circu
3. A list of all of the GPIB IEEE488 Common Commands supported by the LDX 3232 follows CAL CLS ESE ESE ESR IDN OPC OPC PSC PSC PUD PUD RCL RST SAV SRE SRE SESE WAI For more information on these commands refer to an ANSI IEEE 488 1987 standards reference Note Care should be taken to set the GPIB time out appropriately for use with the war DELAY Or OPC Commands If the time for a response after one of these commands exceed the GPIB time out period a bus timeout error will occur Usually after this timeout error the LDX 3232 Series Instrument will generate a query error E302 This error code is reported via the 1 26 LDX 3232 ERR Query Lightwave REMOTE OPERATION LDX 3232 Frequently Used Commands LDX 3232 Frequently Used Commands The LDX 3232 High Compliance Current Source s complete command set contains over 60 commands that allow you to operate the current source for a variety of applications Within the command set however is a smaller subset of commands that will meet most of your needs These commands are listed in Table 3 2 Table 3 2 LDX 3232 Often Used Commands Name Parameters Function ERR NONE Returns errors generated since the last query LAS CALMD 1 Used to set the CAL PD monitor responsivity constant LAS L
4. LDX 3232 1 2 4 INTRODUCTION AND SPECIFICATIONS Initial Inspection Initial Inspection When you receive your LDX 3232 instrument verify that the following items were shipped with the instrument LDX 3232 High Compliance Current Source e LDX 3232 Series Instruction Manual Power Cord Shipping Kit Installing Your LDX 3232 High Compliance Current Source Grounding Requirements The LDX 3232 High Compliance Current Source comes with a three conductor AC power cable The power cable must either be plugged into an approved three contact electrical outlet or used with a three contact or two contact adapter with the grounding wire connected to an electrical ground safety ground The LDX 3232 s power jack and supplied power cable meet IEC safety standards AC Line Power Requirements You can operate the LDX 3232 instrument from a single phase power source delivering nominal line voltages of 100 120 220 240 VAC all values RMS at 50 60 Hz The line power voltage can vary 10 but cannot exceed 250 VAC Maximum power consumption is 60 VA Volt Amps The instrument s operational voltage is factory configurable and need not be changed before operating the instrument However check to be sure that the voltage printed on the back panel of the instrument matches the power line voltage in your area warnine LDX 3232 Before connecting the LDX 3232 High Compliance Current Source to a power source verify that
5. LDX 3232 Current Source OUTPUT Earth Ground Figure 2 4 Common Laser Anode Photodiode Anode The 9 pin connector marked CURRENT SOURCE on the back panel is used to connect your laser diode to the LDX 3232 There are connections provided for laser cathode and anode photodiode cathode and anode chassis ground and interlock The pinout diagram for this connector is shown in Figure 2 5 1 2 Interlock Chassis Ground Cathode Voltage Sense Laser Cathode PD Cathode 4 PD Anode Anode Voltage Sense Laser Anode gt Figure 2 5 Back Panel LD Connector Interlock Connections In order for the laser output to be enabled a short circuit must exist between the Interlock Pins Pins 1 and 2 of the connector The short can be a direct short across the pins or a switch to prevent laser operation until the switch is closed If a short does not exist between these two pins the INTERLOCK LED will illuminate on the front panel and the laser output will be disabled Note The BNC Interlock Connection from the BNC connector on the rear panel will also make the INTERLOCK LED illuminate Please see the notes in chapter five on use of the BNC interlock connection to learn more about its operation A CAUTION The interlock terminals on the LASER connector pins 1 and 2 must be kept isolated from all other connections including earth ground 12 LDX 3232 Lightw
6. PD Bias Adjust LD Connector GPIB Connector Trigger Output Interlock Input Power Cord Fan Connector Connector Connector Figure 1 2 LDX 3232 Rear View A mn Lightwave INTRODUCTION AND SPECIFICATIONS Maintenance Maintenance You may have to return your instrument to the ILX Lightwave facility at some time for repair or service whether or not it is under warranty There is a charge for repairs after the warranty period has expired Contact an ILX Lightwave service representative for shipping instructions prior to returning the instrument Have the model number instrument serial number and a description of the problem or request at the time of the call All ILX Lightwave instruments are identified by a serial number located on the rear panel The first four or five digits are the model number the last four digits are unique to the instrument and identify your instrument specifically A return authorization number will be given to you at the time of your request for repair or service Please use this number in all communications concerning your instrument If you need to ship your LDX 3232 High Compliance Current Source back to the factory for repair be sure that the LDX 3232 is packaged in an enclosure with cushioning material to prevent damage to the instrument during shipment use the original shipping containers and accessories if possible Re install the ESD protective caps on the rear and front panels
7. The default factory settings for this register are shown in Table 3 3 These settings are not affected by the Psc Power On Status Clear command Table 3 3 LDX 3232 Series Default Settings for Output Off Registers 0 disabled 8 1 disabled 9 disabled 2 N A 10 N A 3 enabled 11 N A 4 12 5 N A 13 6 N A 14 N A 7 N A 15 N A Lightwave Logical OR REMOTE OPERATION Status Reporting CHAPTER 3 Enable Register Turn Output Off LASer ENABle OUTOFF lt nrf gt LASer ENABle OUTOFF Figure 3 3 LDX 3232 Output Off Register 0 LASER Current Limit 1 LASER Voltage Limit 2 N A 3 LASER Power Limit output on 4 5 N A 6 7 N A 01 10 8 N A 10 N A 11 12 13 14 15 9 LASER Output Changed to be Out of Tolerance LDX 3232 m 31 REMOTE OPERATION Command Timing and Completion Command Timing and Completion This section describes for each device dependent command whether that command is performed in an overlapped or sequential manner In other words it states whether the next command may begin while the current command is being executed or if the next command must wait until the current command is completed before its execution begins The conditions for setting the operation complete flag are given in the Chapter 3 section titled Operati
8. 01 10 LDX 3232 ix koy db All instruments returned to ILX Lightwave are required to have a Return Authorization Number assigned by an official representative of ILX Lightwave Corporation See Returning an Instrument on page xi for more information SAFETY SYMBOLS This section describes the safety symbols and classifications Technical specifications including electrical ratings and weight are included within the manual See the Table of Contents to locate the specifications and other product information The following classifications are standard across all ILX Lightwave products Indoor use only Ordinary Protection This product is NOT protected against the harmful ingress of moisture Class Equipment grounded type Mains supply voltage fluctuations are not to exceed 10 of the nominal supply voltage Pollution Degree II Installation overvoltage Category II for transient overvoltages Maximum Relative Humidity 8096 RH non condensing Operating temperature range of 0 C to 40 Storage and transportation temperature of 40 C to 70 Maximum altitude 3000 m 9843 ft This equipment is suitable for continuous operation Safety Marking Symbols This section provides a description of the safety marking symbols that appear on the instrument These symbols provide information about potentially dangerous situations that can result in death injury or damage to the instrument and other components Caution Ea
9. All of the above radixes may be used to enter program data at any time without the need for issuing the RADix command The proper prefix must also be used with Hex H binary B or octal Q This command may be useful for setting up status reporting blocks The bit wise status representation may be more easily read in BIN HEX or OCT RAD dec action the decimal radix is selected LDX 3232 79 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference rad hex ESR action the hexadecimal radix is selected H80 means power on was detected RADix Notes Examples REMOTE The RADix query allows the programmer to determine that radix type for status condition and event query response data is currently selected Decimal binary octal and hexadecimal are allowed Op where the character response data of DEC means decimal BIN means binary HEX means hexadecimal and OCT means octal DEC is the default type The LDX 3232 defaults to this radix at power up The RADix command is used to select the desired radix Once it is changed the new radix will remain in effect until the power is shut off or a new RADix command is issued RAD response Dec means the selected radix is decimal rad response Hex means the selected radix is hexadecimal RADIX response Oct means the selected radix is octal SECURE REMOTE The SECURE command allows the service te
10. To set the LDX 3232 in Constant Power mode select P in the MODE section of the front panel by toggling the SELECT push button Repeatedly pressing the MODE SELECT switch cycles through the current l light power P or high bandwidth current l4gw control modes The LED indicator shows the selected mode Entering Photodiode Responsivity Values The photodiode responsivity CAL photodiode is n used to convert between photodiode current and optical power of the laser diode To enter the sali uM photodiode parameter select CAL PD with the CAL PARAMETER SELECT push button by toggling 1 div down past LIM P The indicator becomes lit when SET CAL PD is selected and the display indicates the responsivity parameter in pA mW not an nunciated Rotate the adjust knob after pressing the PARAMETER SET push button to enter a new value for responsivity After three seconds the new parameter value is stored in non volatile memory 01 10 LDX 3232 17 OPERATION Operating a Laser in Constant Power P Mode A method to calculate the responsivity is suggested below 1 Measure with a calibrated detector the output power of the device 2 Measure the corresponding photodiode current 3 Calculate the responsivity by dividing the photodiode current by the optical power noting the units required are LA mW The LDX 3232 High Compliance Current Source can be put into a special mode with t
11. s Trigger Function For applications where you need to synchronously initiate a measurement task from a remote instrument with the LDX 3232 Current Source the Current Source offers a trigger output signal The TTL pulse is initiated with any remote change in setpoint of the laser current source A typical application for utilization of this feature is laser characterization tasks where an L I curve is generated For a programmed step in laser current a light measurement can be triggered for each step in laser current The trigger output is enabled only in remote mode via the GPIB IEEE 488 GPIB Interface The trigger output is available via a standard BNC connector on the rear panel of the LDX 3232 Current Source See Figure 5 1 The TTL pulse is approximately 13 us wide and has a delay time of about 10 12 ms after the current setpoint is changed via GPIB This delay does not include the GPIB transmission time The time for any command to be sent via GPIB depends on the interface hardware and software control The current setpoint may be changed by the LAS LDI LAS INC or LAS DEC commands Note The minimum step change time required for a corresponding trigger pulse is 20 ms Care should be used with respect to the timing of any setpoint commands in relation to the actual hardware function The INC and DEC commands have a minimum step time of about 20 ms that allows for the hardware initiation of a setpoint change and the settling of the output
12. 0 31 seconds since the last TIMER query was issued TIMER response 00 00 12 03 means the LDX 3232 has been on for 12 03 seconds since the last TIMER query was issued 82 LDX 3232 Lightwave 01 10 CHAPTER 5 EATURES FUNCTIONS AND a m El Bl a a a a El El a a El a Bi Ei a This chapter introduces you to the LDX 3232 High Compliance Current Source functions and operating features such as event triggering analog modulation of laser injection current and Save and Recall Saving and Recalling from the Front Panel For applications where you might need to alternate between particular instrument configurations the LDX 3232 Current Source offers a unique SAVE and RECALL feature The SAVE feature allows you to easily store all front panel settings for any given instrument configuration These settings that are stored in one of ten memory bins can be retrieved at any time with the RECALL function This saves setup time and it reduces the chance of setup error for tests that are periodically repeated For example using the configuration described in Chapter 2 where the Current Source is operating in Constant Current mode the instrument parameters saved by using the SAVE function would be Constant Current Mode 2000 mA range a limit setpoint of 1750 mA a laser current setpoint of 1500 mA and Display Mode Once this setup is saved the LDX 3232 Current Source may be configured for another unique setup You can recall
13. 32 N A 8192 N A 64 N A 16384 N A 128 NA 32768 N A Notes The enabled LASER events can be set by using the LASer ENABle OUTOFF command The LASER output status can be monitored by the LASer EVEnt query Examples LAS ENAB OUTOFF response 1 means that Current Limit Condition will cause the LASER output to be turned off Radix Hex Las Enab Eve response H20B means that all of the above conditions will cause the LASER output to be turned off 01 10 LDX 3232 59 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer EVEnt FRONT PANE REMOTE The LASer EVEnt query returns the value of the status event register of the LASER operations Syntax Diagram where the response is the sum of the following 1 LASER Current Limit 256 Output is shorted 2 LASER Voltage Limit 512 Output changed to be in out of tolerance 4 N A 1024 Output on off state changed 8 Power limit 2048 Measurement ready 16 Interlock disabled 4096 N A 32 N A 8192 N A 64 Compliance Voltage Limit 16384 N A 128 Open circuit 32768 Notes The LASER conditions that are reported in the status byte can be set by using the LASer ENABle EVEnt command The LASER event status is only cleared when the event status is read or by the CLS command while the condition status is constantly changing Examples LAS EVE response 513 means that the LASER output tolerance changed and current limit events have occurred since the last LASer EVEn
14. 52 LDX 3232 None This command has the same effect as pressing the PARAMETER SELECT switch while in LASER mode The selected parameter will be displayed for three seconds The actual LASER PARAM display is turned off automatically when a display selection is enabled Each time the command is issued the next LASER parameter will be selected see Chapter 2 for more information Laser Display Param action selects a parameter and displays its value LAS DIS PARAM action selects a parameter and displays its value Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer DISplay SET FRONT PANEL REMOTE The LASer DISplay SET command sets the display to show the setpoint of the selected display mode Syntax Diagram Parameters None Notes Using this command has the same effect as physically holding the DISPLAY SELECT switch down continuously Examples Las Dis Set action enables the display for the setpoint of the selected mode LDI MDI 1 or MDP Ppp LAS Dis Set action enables the display for the setpoint of the selected display mode 01_10 LDX 3232 m 53 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer DISplay SET REMOTE The LASer DISplay SET query returns the status of the setpoint display mode Syntax Diagram PO HOR LOX PO where the response is 0 or 1 Notes The setpoint display will not time out when REMOTE operation is used It
15. LDX 3232 Device Dependent Command Reference LASer ENABle EVEnt FRONT PANI REMOTE The LASer ENABle EVEnt query returns the value of the status event enable register of the LASER operations Syntax Diagram POA po where the response is the sum of the following 1 LASER Current Limit 256 Output is shorted 2 LASER Voltage Limit 512 Output changed to be in out of tolerance 4 N A 1024 Output on off state 8 Power limit 2048 New measurements taken 16 Interlock state changed 4096 N A 32 N A 8192 N A 64 Compliance Voltage Limit 16384 N A 128 Open circuit 32768 N A Notes The enabled LASER events can be set by using the LASer ENABle EVEnt command The LASER event status can be monitored by the LASer EVEnt query Examples LAS ENAB EVE response 1040 means that the Output on off state change and Interlock changed LASER events will be reported in summarized form to the status byte register bit 2 Radix Hex Las Enab Eve response HFDB means that all of the above events will be reported in summarized form to the status byte register bit 2 01_10 LDX 3232 57 58 LDX 3232 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer ENABle OUTOFF REMOTE The LASer ENABle OUTOFF command sets the status outoff enable register of the LASER operations things that will turn the LASER output off Syntax Diagram Parameters 1 2 4 8 16 32 64 128 Notes Examples An l
16. Linking the LDX 3232 Current Source to a temperature controller with the ability to signal when its temperature control has gone outside of some tolerance window will allow the LDX 3232 to safely shutoff its output before thermal damage occurs to the laser diode The ILX Lightwave LDT 5900 series of temperature controllers include an output BNC connector that is compatible with the BNC interlock feature of the LDX 3232 The output BNC connector of the LDT 5900 has a TTL compatible output signal that will signal when the temperature control has gone outside of a programmable temperature window For more information about the LDT 5900 series of temperature controllers please call 1 800 459 9459 USA or Canada only 1 406 556 2481 International or go to www ilxlightwave com Modulating the Laser Current Source The LDX 3232 Current Source allows a modulated signal to be superimposed on the source output current For example assume you are using an LED for your experiment where you need to operate the LED in constant current at Pop 100 mW with a modulated signal from 3 to 30 kHz The experiment requires the LDX 3232 s laser Current Source to be configured for the 2000 mA range high bandwidth mode with a limit of 1750 mA The allowable bandwidth of the modulated analog signal defined as the 3 aB roll off point is dependent on the output current range and the mode constant current low high bandwidth See the section LASER CURRENT SOURCE
17. Maximum output current transient resulting from a 1000 V power line transient spike Tested to ILX Lightwave Technical Standard LDX 00196 LDX 3232 7 INTRODUCTION AND SPECIFICATIONS _ Specifications 8 Maximum monitor photodiode current drift over any 30 minute period Assumes zero drift in responsivity of photodiode 9 50 modulation at mid scale output Higher bandwidth is possible with smaller magnitude modulation signal 10 Similar resolution available over GPIB 11 Responsivity value is user defined and is used to calculate the optical power 12 Four wire voltage measured at the load Voltage measurement accuracy while driving calibration load Accuracy is dependent upon load and cable used Available Options and Accessories Options and accessories available for the LDX 3232 High Compliance Current Sources include the following DESCRIPTION MODEL NUMBER Noise Filter LNF 320 Current Source Interconnect Cable terminated CC 305S Current Source Interconnect Cable unterminated CC 306S DIL Laser Diode Mount LDM 4982 Butterfly Laser Diode Mount LDM 4894 High Power Laser Diode Mount LDM 4442 Single Rack Mount Kit RM 139 Dual Rack Mount Kit RM 140 Other laser diode mounts are available Please contact ILX Lightwave for information on additional options for your application Our goal is to make the best laser diode instrumentation available anywhere To achieve this we need your
18. Notes In local operation the MDI setpoint is read by selecting P mode then pressing and holding down the SELECT switch the DISPLAY area of the front panel When the pA indicator is blinking the display will show the MDI setpoint The monitor photodiode current is directly proportional to the laser optical output power Therefore the MDI lpp setpoint may be used to control optical output of the laser Examples las set mdi response 30 0 means the laser monitor photodiode current is setpoint is 30 uA for use in constant P mode with CALPD 0 01 10 LDX 3232 75 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LAS Set MDI response 100 0 means the laser monitor photodiode current is setpoint is 100 LA for use in constant P mode with CALMD 0 LASer SET MDP FRONT PANEL REMOTE The LASer SET MDP query returns the laser monitor photodiode power setpoint value when CALMD CAL PD is not zero in mW where the response is the constand P setpoint in mW Notes In local operation the MDP setpoint is read by selecting P mode then pressing and holding down the SELECT switch in the DISPLAY area of the front panel When the mW indicator is blinking the display will show the MDP setpoint This setpoint is used in constand MDP mode only Examples LAS Set MDP response 10 0 means the laser monitor photodiode feedback setpoint is 10 0 mW CALPD gt 0 Laser Set MDP response 25 0 mean
19. compliance voltage Check to see if the LASER voltage limit setting is too low Chapter 2 check laser connections Lightwave CALIBRATION AND TROUBLESHOOTING Error Messages CHAPTER 6 Error Messages In the event of a hardware error condition error messages will be displayed on the display In most cases the error message will appear for three seconds In some cases the error code display will remain until the user changes display modes In the case of multiple error messages the display may sequentially show each message for three seconds In addition to the hardware errors GPIB errors may be read via the ERR query Table 3 4 lists the numerical error ranges by function Table 3 5 contains all of the error messages that may be generated Not all of these messages may appear on the front panel displays Some refer to GPIB activities only In remote operation the errors can be read by issuing the ERR query When this is done all of the error messages that are resident in the error queue are returned up to 10 may be stored Reading the error queue via GPIB clears the error queue Table 6 3 Error Code Classifications Error Code Range Area of Operation E 001 to E 099 Internal Program Errors E 100 to E 199 Parser Errors E 200 to E 299 Execution Control Errors E 300 to E 399 GPIB Errors E 500 to E 599 LASER Control Errors Table 6 4 LDX 3232 Series Error Codes
20. display will indicate a current in mA Input the first actual measured output current as an nrf value gt via the LAS LDI lt nrf value gt command If this value is to be measured and entered remotely via a GPIB controlled DMM for example the measured value of the current should not be entered until the LDX 3232 Series Current Source is ready to receive it The Current Source will be ready to receive the new measured value when after a LAS CAL LDI query is sent the response from the Current Source is 1 Once the newly measured value is entered via the LAS LDI command the Current Source will apply a new current equal to about 25 of the previous set current Input the second actual measured output current as an lt nrf value gt asin Step e Once the second actual value is entered via the LAS LDI command the new calibration constants will be calculated and stored into non volatile memory In low bandwidth calibration mode the LDX 3232 Current Source will also perform current limit calibration as indicated by the CURRENT LIMIT LED flashing The oPC query may be used after the LAS LDI value is sent to determine when the calibration is completed Or wait about two seconds before continuing with other GPIB commands Turn the current source output off Change the Mode to high bandwidth constant current mode with the LAS THBW command Repeat the calibration procedure as described above Ipp Curre
21. 3232 m 39 40 COMMAND REFERENCE _ LDX 3232 Device Dependent Command Reference LDX 3232 Device Dependent Command Reference LDX 3232 The following pages contain a reference for the device dependent commands of the LDX 3232 High Compliance Current Source This reference contains useful information for both local and remote operation of the LDX 3232 References to the front panel labels are capitalized in the following reference pages as is done throughout this manual Therefore a reference to the LOCAL switch is meant to signify the actual switch labeled LOCAL on the front panel of the LDX 3232 In some reference parentheses are used to signify the labeled are for a particular switch or LED indicator on the front panel For example PARAMETER SET refers to the switch labeled SET in the PARAMETER area of the front panel DELAY REMOTE The DELAY command causes the execution of commands to be delayed by a user defined time This command is similar to the WAl common command except that execution resumes after the specified number of miliseconds instead of waiting for the Operation Complete flag to be set Syntax Diagram lt white nrt space gt value gt Parameters nrf value that represents the delay time in milliseconds Notes The Operation Complete flag is held false until the delay period elapses but the OPC query will not execute until the delay period has elapsed This comman
22. DMM with 0 1 mV resolution to measure the voltage across the resistor R1 as shown in Figure 6 1 Calculate the current in the following steps by using Ohm s Law where V is the accurately measured voltage across the resistor R is the accurately measured load resistance is the actual photodiode current to be measured by the LDX 3232 Current Source A 4 wire Kelvin resistance measurement is recommended b Press the MODE ON switch to turn the current source output on Verify proper operation i e the measurement via DMM and setpoint should be close and the unit should not be in current limit c Press the GPIB LOCAL and FINE switches at the same time to place the Current Source in its Current Calibration mode After a few seconds the display will show the lpp setpoint value d X After the value on the display is stable has not changed by more than one digit for several seconds the LDX 3232 Current Source is ready for the actual lpp value to be entered Press and hold in the PARAMETER SET switch and turn the adjust knob until the display shows the actual monitor current as shown on the calibrated ammeter or the calculated lpp value from Step a e Release the PARAMETER SET switch to store the first calibration value The Current Source will then set the second calibration current approximately one fourth 1 4 of the original current For example if the first calibration setpoint wa
23. FALSE 0 SET 1 RESET 0 01 10 LDX 3232 m 23 REMOTE OPERATION LDX 3232 Current Source Command Set If multiple parameters are expected they should be separated with commas LAS INC 100 50 A query has no space between the mnemonic and the question mark LAS LDI The LDX 3232 High Compliance Current Source uses a terminator of NL END new line with EOI For users whose GPIB driver defaults expect a carriage return in the terminator CR NL END the TERM command may be used for convenience see TERM command in Chapter 4 For more information refer to your GPIB driver configuration manual The command structure is illustrated in Figure 3 1 Table 4 1 lists all of the LDX 3232 High Compliance Current Source s device dependent commands with the full path shown for each command and a brief explanation of its usage 24 m LDX 3232 Lightwave Paths REMOTE OPERATION Command Paths The LDX 3232 High Compliance Current Source device dependent commands are structured into a tree format see Figure 3 1 Each of the legal paths is listed below followed by its list of path options each of that is followed by the commands themselves It is recommended that the first time user begin learning the commands by using the full path notation Once you are familiar with the commands you may wish to take advantage of the shortcuts allowed for command paths root com cmd
24. LDX 3232 is in Constant Current Mode l in the 2000 mA range and the display is reading in mA Next we need to adjust the setpoint of the laser current source To adjust the setpoint of the current source to 1500 mA turn the adjust knob to vary the setpoint When the adjust knob is turned the LDX 3232 automatically changes to setpoint mode indicated by the flashing annunciator Adjust the setpoint to 1500 mA After an adjustment has been made and the adjust knob is released the setpoint mode will time out in three seconds The display will revert to the original measurement display mode 1 lpp V or Ppp The instrument is still not ready to turn on the laser One of the laser protection features our precision current sources offer is a fully independent hardware current limit The current limit protects your laser by never allowing the laser drive current to exceed the limit independent of the setpoint and the output control mode Constant Current or Constant Power LDX 3232 15 OPERATION Operating a Laser in Constant Current I Mode PERGNGR To set the current source limit use the SELECT push button in the PARAMETER section of the front da wi panel to select LIM Press the PARAMETER sgg UMP SET push button and rotate the adjust knob to vary CALPD ma the limit setpoint value After three seconds the compy parameter value is stored in non volatile SET memory When the LASER current
25. Lo DOT in a container with at least 3 inches 7 5 cm of compressible packaging material on all sides We look forward to serving you even better in the future xiv LDX 3232 Lightwave 01 10 CHAPTER 1 INTRODUCTION AND SPECIFICATIONS E a m a a a H a El El la EH El El a This chapter is an introduction to the LDX 3232 High Compliance Current Source This chapter contains first time setup information important safety considerations maintenance information instrument specifications and general LDX 3232 information AJ warnine If any of the following symptoms exist or are even suspected remove the LDX 3232 from service Do not use the LDX 3232 until trained service personnel can verify safe operation Visible damage Severe transport stress Prolonged storage under adverse conditions Failure to perform intended measurements or functions If necessary return the LDX 3232 to ILX Lightwave for service and repair to ensure that safety features are maintained Product Overview The LDX 3232 instrument is a high compliance laser diode current source intended for use with quantum cascade laser diodes and other devices requiring a high compliance output The LDX 3232 current source provides a high stability output with multiple laser protection features and a fully redundant current limit The LDX 3232 offers the added benefits of dual laser interlocks and a GPIB interface to allow full automation of testing
26. PARAM NONE Enables LASER display to show parameter values LAS DIS SE NONE Shows the LASER display setpoint corresponding to mode LAS DIS SET NONE Returns status of LASER setpoint display on off LAS ENAB COND 1 Sets the enable register for LASER conditions LAS ENAB COND NONE Returns the value of the LAS conditions enable register LAS ENAB EVE 1 Sets the enable register for LAS events LAS ENAB EVE NONE Returns the value of the LAS event enable register LAS ENAB OUTOFE 1 Sets the enable register for LAS conditions that turn the LAS output off LAS ENAB OUTOFF NONE Returns the value of the LAS outoff enable register LAS EVENT NONE Returns the value of the LAS event register LAS LDI 1 Used to set the LASER constant current source setpoint value LAS LDI NONE Used to return the constant current source measured value LAS INC 0 1 or2 Used to increment the LASER setpoint value by one or more steps LAS LDV 1 Used to set the laser voltage value for calibration LAS LDV NONE Used to return the measured laser voltage value Lightwave COMMAND REFERENCE T W Mi A i CHAPTER 4 Name Parameters Function AS LIM 12 1 Used to set the LASER low range current source limit AS LIM 12 NONE Used to return the LASE
27. PO Q where the response is 0 or 1 Notes In local operation the status of the LDV measurement mode is indicated by the enunciator next to the display V will be illuminated when the display is in LDV measurement mode Examples LAS DIS LDV response 0 means that laser voltage measurement is not displayed LAS DIS LDV response 1 means that the laser voltage measurement is displayed LASer DISplay MDI FRONT PANEL REMOTE The LASer DISplay MDI command sets the laser display to show the monitor photodiode current measurement Syntax Diagram POP OX PHC Parameters None Notes The MDI measurement display is turned off automatically when another display selection is enabled Examples LAS DIS MDI action enables the display for photodiode current measurement values Laser Disp Mdi action enables the LASER display for photodiode current measurement values 50 LDX 3232 Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer DISplay MDI REMOTE The LASer DISplay MDI query returns the status of the LASER DISPLAY lpp switch Syntax Diagram POR PC where the response is 0 or 1 Notes In local operation the status of the MDI measurement mode is indicated by the enunciator next to the display uA will be illuminated and not blinking when the display is in MDI measurement mode Examples LAS DIS MDI response 0 means that the laser photodiode monitor cur
28. Precision Current Source Set the LDX 3232 in Constant Current low bandwidth mode by selecting in the MODE section of the front panel Do this ei E by toggling the SELECT push button until the indicator is a illuminated Repeatedly pressing the MODE SELECT m Hew switch cycles through the current l light power P or on high bandwidth current l4agw control modes ouve Next the RANGE section set the current source range by ran selecting the 2000 mA range indicated by the accompanying LED You will need to press the SELECT push button twice eS to change the range It must be pressed twice quickly within less than 1 second to switch between ranges and the 3 LASER output must be off LASER MODE ON indicator PRESS TWICE unlit in order to change ranges Configure the display so that it reads laser current in mA Press and release the SELECT switch in the DISPLAY section of the front panel until the mA annunciator is lit The DISPLAY SELECT switch is also used to select the lpp PD current LA Ppp laser power mW or V forward voltage V measurement or setpoint display modes When the setpoint mode is active the corresponding annunciator will flash to indicate setpoint rather than measurement display To only view the setpoint press and hold down the display SELECT switch for two or more seconds When the SELECT switch is released the previous measurement mode will be restored At this point the
29. Returns the laser constant optical power setpoint AS SET MDP NONE Returns the constant P optical power setpoint AAS STEP 1 Used to set the LASER setpoint step value AS STEP NONE Returns the LASER setpoint step value AS TOL 2 Used to set the LASER setpoint tolerance value and time period value 01 10 LDX 3232 37 Name Parameters Function LAS TOL NONE Used to return the LASER setpoint tolerance value and time period value MES 1 Used to enter a string message of up to 16 bits MES NONE Returns a previously stored ASCII message RAD 1 Sets the radix type for numerical data decimal binary octal or hexadecimal RAD NONE Used to return the radix type for numerical data ERI 1 Used to add a carriage return to the device terminator ERM NONE Returns the status of the TERM command IME NONE Returns the elapsed time since the instrument was last powered up IMER NONE Returns the elapsed time since the timer was last reset 38 m LDX 3232 Lightwave 01 10 COMMAND REFERENCE LDX 3232 Device Dependent Commands LDX 3232 Device Dependent Commands This section contains all of the device dependent commands for the LDX 3232 High Compliance Current Source listed in alphabetical order Sub sections for each path are presented listing the commands that are legal for that path See Figure 3 1 for command path tree structure Command Path Name Required l
30. Start with the low range After calibration is complete in this range switch to the high range and repeat the procedure Configure the current source in the following manner for the laser current source calibration Function State GPIB COMMAND LASER MODE constant current low bandwidth AS MODE ILBW RANGE Low lowest per instrument model LAS RAN x LIMIT 90 of FS full scale of range LAS LIM Ix SETPOINT 8096 of FS LAS LDI 01 10 LDX 3232 95 96 LDX 3232 CALIBRATION AND TROUBLESHOOTING Remote Calibration of the LDX 3232 Current Source Measure and record the resistance of a 1 Q 20 W resistor A 4 wire Kelvin resistance measurement is recommended Connect the load resistor across the LASER output terminals Laser Anode and Laser Cathode on the 9 pin connector of the rear panel Connect the calibrated DMM across the load resistor Configure the multimeter to measure voltage in volts You will be calculating the actual Laser current in the following manner using Ohm s Law where V is the accurately measured voltage across the resistor R is the accurately measured load resistance in Ohms lis the actual Laser current in Amps The current source output must be on in order to enter the LASER calibration mode Enter the LAS OUTPUT ON command to turn the current source output on Enter the LASER calibration mode by issuing the LAS CAL LDI command The
31. The LDI measurement display mode is turned off automatically when another display selection is enabled Examples LAS DIS LDI action enables the display for current values 48 m LDX 3232 Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer DISplay LDI FRON REMOTE The LASer DISplay LDI query returns the status of the LDI measurement display mode Syntax Diagram eo PO G where the response is 0 or 1 Notes In local operation the status of the LDI measurement display mode is indicated by the enunciator next to the display mA will be illuminated and not blinking when the display is in LDI measurement mode Examples LAS DIS LDI response 0 means that the LDI measurement is not displayed Las dis ldl response 1 means that the LDI measurement is displayed LASer DISplay LDV FRONT PANEL REMOTE The LASer DISplay LDV command sets the laser display to show the laser forward voltage measurement Syntax Diagram C e Parameters None Notes The LDV measurement mode is turned off automatically when another display selection is enabled Examples LAS DIS LDV action enables the display for LDV measurement mode 01_10 LDX 3232 49 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer DISplay LDV REMOTE The LASer DISplay LDV query returns the status of the LDV laser diode voltage measurement display mode Syntax Diagram 9o
32. Usage Example 86 Modulating the Laser Current Source 86 Chapter 6 Calibration and Troubleshooting Calibration Overview 89 Recommended Equipment 90 Local Calibration of the LDX 3232 Current Source 91 Current Source Calibration 91 lpp Current Calibration 92 Laser Forward Voltage Measurement Calibration 94 Remote Calibration of the LDX 3232 Current Source 95 Current Source Calibration 95 lpp Current Calibration 96 Laser Forward Voltage Measurement Calibration 98 Troubleshooting Guide 99 Error Messages 101 01 10 LDX 3232 iii ann pee ens iv LDX 3232 Lightwave LIST OF FIGURES Figure 1 1 LDX 3232 Front View 4 Figure 1 2 LDX 3232 Rear View 4 Figure 2 1 Common Laser Cathode Photodiode Cathode 11 Figure 2 2 Common Laser Cathode Photodiode Anode 11 Figure 2 3 Common Laser Anode Photodiode Cathode 11 Figure 2 4 Common Laser Anode Photodiode Anode 12 Fig
33. actual current output of the current source Current Source Calibration The following procedure is for calibrating each range of the current source Calibration must be performed on both bandwidth modes A total of four calibrations will be performed on the current source Start with the low range low bandwidth mode Configure the Laser Current Source in the following state Function State MODE constant current low bandwidth RANGE low lowest per instrument model CURRENT LIMIT 9096 of FS full scale of range SETPOINT 8096 of FS 01 10 LDX 3232 91 CALIBRATION AND TROUBLESHOOTING Local Calibration of the LDX 3232 Current Source a Measure and record the resistance of a 10 20 W resistor A 4 wire Kelvin resistance measurement is recommended Connect the load resistor across the LASER output terminals Laser Anode and Laser Cathode on the 9 pin connector of the rear panel b Connect the calibrated DMM across the load resistor Configure the multimeter to measure voltage in volts You will be calculating the actual Laser current in the following manner using Ohm s Law where V is the accurately measured voltage across the resistor R is the accurately measured load resistance in Ohms is the actual Laser current in Amps Note Check the current measuring range of your multimeter You may be able to measure Laser Output current in mA by connecting the meter directly to
34. limit is reached the CURRENT LIMIT error indicator flashes The current limit setting is independent of the voltage drop of the device connected to the LASER output and therefore no dummy load is required for precise adjustment of the current limit Furthermore since the current limit circuitry is fully independent of the main current control the current limit can be adjusted safely even while the LASER output is active An additional feature of the LDX 3232 instrument is an adjustable voltage limit This allows an extra level of laser protection in the event of an intermittent open circuit For maximum protection via the fastest open circuit detection the voltage limit should be set to a value slightly greater than the intended operating voltage To set the LASER voltage limit use the SELECT push button in the PARAMETER section of the front panel to mei Ei select COMP V and then press the PARAMETER SET P SELECT push button to adjust the voltage limit using the adjust knob Now you ready enable the current source output for your laser diode In the MODE section of the front panel press the push button labeled OUTPUT The accompanying LED labeled ON will illuminate indicating that the laser current source s output is enabled The instrument will drive the current source to the value set by the corresponding MODE setpoint When the LASER output is off an internal short is placed across the LASER outpu
35. only necessary to turn the current source output off It is also recommended that the connections to the LDX 3232 output be made using twisted wire pairs with an earth grounded shield see Figures 2 1 2 4 The output terminals of the instrument are left floating relative to earth ground to suppress AC power on power off transients that may occur through an earth ground path If the output circuit is earth grounded at some point such as through the laser package and mount the user must be careful to avoid multiple earth Lightwave OPERATION Connecting to the Laser grounds in the circuit Multiple earth grounds may provide circuit paths that induce spurious currents in the photodiode feedback circuit and output leads Note Cable connections to the laser must be secure Loose connections can cause momentary open circuits that can damage the laser Figures 2 1 2 4 show the possible configurations of connecting laser diodes and photodiodes with the LDX 3232 High Compliance Laser Current Source LDX 3232 Current Source OUTPUT Earth Ground Figure 2 1 Common Laser Cathode Photodiode Cathode OUTPUT LDX 3232 Current Source Earth Ground Figure 2 2 Common Laser Cathode Photodiode Anode OUTPUT LDX 3232 Current Source Earth Ground Figure 2 3 Common Laser Anode Photodiode Cathode 01_10 10 3232 11 OPERATION Connecting to the Laser
36. output This short will prevent the modulation signal from reaching the LED in our example experiment Thus it is safe to disconnect the test device LED when the LDX 3232 s output is off regardless of the presence of the modulation signal 88 LDX 3232 Lightwave 01 10 CHAPTER 6 CALIBRATION AND TROUBLESHOOTING a a B m El a H El El a El El a Hi m a This chapter describes calibration of your LDX 3232 Series Current Source Descriptions of the required test instruments calibration conditions and the detailed procedures for calibration of the instrument s Laser Diode Current Source are included A troubleshooting guide is also offered for some of the more common failure symptoms This chapter is divided into three major sections local front panel calibration remote through the GPIB Interface calibration and a troubleshooting guide Calibration Overview There are several calibrations to be performed to completely calibrate your LDX 3232 Current Source The Laser Diode Current Source calibration consists of calibrating the current source in both ranges and both modes low and high bandwidth calibrating the photodiode monitor feedback ammeter and finally the forward voltage measurement The current limits are calibrated internally by the instrument as part of the calibration process Your LDX 3232 Current Source can be calibrated with the case closed It should be calibrated every 12 months or whenever performanc
37. over the connectors 9 pin D BNC and GPIB Shipping damage is not covered under warranty Attach a tag to the instrument identifying the owner and indicating the service or repair needed Include the model number and serial number We suggest that you insure the shipment In North America contact ILX Lightwave for return authorization and shipping instructions Outside of North America contact your ILX distributor for shipping information For more information on how to obtain repair services see the Safety and Warranty section of this manual If cleaning is required use a clean dry cloth Do not use solvents AA warnine Potentially lethal voltages exist within the LDX 3232 High Compliance Current Source To avoid electric shock do not perform any of the maintenance on the instrument unless you are qualified to do so Qualified service personnel are required to wear protective eyeglasses and anti static wristbands while working on the LDX 3232 High Compliance Current Source circuit boards High voltages are present on and around the instrument s printed circuit boards 01_10 LDX 3232 5 aK m 1 INTRODUCTION AND SPECIFICATIONS CHAPTER Specifications 6 E Specifications LDX 3232 Drive Current Output Output Current Range 0 to 2000 mA 0 to 4000 mA Setpoint Resolution 40 uA 80 uA LDX 3232 Setpoint Accuracy 0 15 of SP 2 mA 0 15 of SP 2 mA Compliance Voltage 0 15 V adju
38. place the Current Source in its LASER Current Calibration mode The Current Source will increase the laser current output until the current at the PD monitor Ipp inputs equals the targeted setpoint After a few seconds the Current Source will be ready for the actual lpp current to be entered via the LAS MDI nrf value command The measured value of the current should not be entered until the Current Source is ready to receive it The Current Source will be ready to receive the current value when after a LAS CAL MDI query is sent the response from the Current Source is 1 Once the actual lpp value is entered via the LAS MDI nrf value command the Current Source will store the new calibration value It will then set the output to approximately one fourth 1 4 of the original current For example if the first calibration setpoint was 4000 pA the second setpoint will be 1000 pA Then it will be ready to receive the second calibration value Input the second actual measured monitor diode current as an nrf value as in Step d Once the second actual IPD value is entered via the LAS MDI command the new calibration constants will be calculated and stored into non volatile memory The OPC query may be used after the LAS MDI value is sent to determine when the calibration is completed Or wait about two seconds before continuing with other GPIB commands LDX 3232 97 98 LDX 3232 CALIBRATION AND TROUBLES
39. the instrument is useful for programming synchronization The Output Off Register section also contains iformation on setting some of the conditions that will force the laser current source output off The following sections describe the Event and Condition registers Operation Complete Flag Output Off registers and Error Messages Event and Condition Registers In addition to the required GPIB IEEE488 status reporting structures the LDX 3232 High Compliance Current Source remote interface provides Event and Condition Registers for LASER operations The Event Registers are used to report events that occur during the operation of the LDX 3232 High Compliance Current Source Events differ from conditions in that events signal an occurrence once and are not reset until the Event Register is queried the status cleared by the CLS command or the instrument is powered off Conditions reflect the current state of the device and therefore may change many times during operation Querying a Condition Register does not change its contents Figure 3 3 shows the status reporting scheme of the LDX 3232 High Compliance Current Source Each of the registers that may be accessed by a command or query has the appropriate command or query written above or below the register representation For example the LASER Condition Register may be queried via the LASer COND query The condition or event registers are logically ANDed with their respective enable reg
40. the modulated current as well protecting your laser in any mode To accomplish setting the current source limit use the PARAMETER SELECT push button LIM I Press the PARAMETER SET push button and rotate the adjust knob Set the limit to 1750 mA Once the PARAMETER SET push button is released the new parameter value is stored in non volatile memory When the laser current limit is reached the CURRENT LIMIT error indicator flashes The current limit setting is independent of the voltage drop of the device connected to the laser output and therefore no dummy load is required for precise adjustment of the current limit Furthermore since the current limit circuitry is fully independent of the main current control the current limit can be adjusted safely even while the current source output is active Now you are ready to modulate the laser injection current To enable the Current Source output press the push button labeled MODE OUTPUT The accompanying LED labeled ON will illuminate indicating that the laser current source s output is enabled The instrument will drive the current source to the value set by the corresponding MODE setpoint Turn on the function generator modulation source to inject the modulation signal LDX 3232 87 FUNCTIONS AND FEATURES Modulating the Laser Current Source To disable the output press the OUTPUT push button again When the LDX 3232 current output is off an internal short is placed across the
41. 20 pA of photodetector current but photodiode monitor current is not controlling the laser output current Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer MDLN REMOTE The LASer MDLN command enables or disables turns off the front panel modulation lt white nrf space gt value gt input BNC Syntax Diagram Parameters nrf value where 1 on O off Notes After turning the modulation off it will remain off until turned back on via this command or by resetting the instrument Examples las mdin 1 action turns the modulation input on and enables modulation via the front panel BNC connector Laser mdln 0 action turns the modulation input off Modulation signals at the front panel BNC will not effect the LAS output LASer MDLN REMOTE The LASer MDLN query returns that status of the LAS modulation control When disabled a modulation signal at the front panel BNC will not effect the LAS output Syntax Diagram where the response of 1 on Ozoff Notes The LASER modulation control switches the front panel BNC in and out of the LAS control circuit At power up or after reset modulation is enabled by default Examples LAS MDLN response 1 means that the LAS modulation input is enabled las mdin response 0 means that the LAS modulation input is disabled 01 10 LDX 3232 69 COMMAND REFERENCE LDX 3232 Device Dependent Command Refe
42. 4096 N A 8192 Compliance Voltage Limit 16384 Open circuit 32768 Output is shorted Output is outside tolerance limit Output on off state Ready for calibration data state N A N A N A N A The LASER conditions that are reported to the status byte are set via the LASer ENABle COND command The Open circuit condition is only present while the LASER output is on and when the hardware detects this condition it will turn the LASER output off Therefore the Open Lightwave 01 10 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference Circuit condition is fleeting and may be missed via the LAS COND query Therefore the user should test for the Open Circuit Event via the LAS EVEnt query The LASER condition status is constantly changing while the event status is only cleared when the event status is read or the CLS command is issued Examples LAS COND response 513 means that the LASER limit current and out of tolerance LASER conditions currently exist Radix Hex Laser Cond response H108 means that the LASER Output shorted and Power limit conditions currently exist LASer DEC The LASer DEC command decrements the selected laser control mode setpoint by one step This is an overlapped command Other commands may be executed while this function is in progress Syntax Diagram COCs HC Parameters None Notes The decremental default amount is one step The step size can
43. 67 68 LDX 3232 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer MDI FRONT PANEL REMOTE The LASer MDI command sets the value of the optical power setpoint in if the CALMD CAL PD responsivity is 0 Syntax Diagram lt white space gt Parameters nrf value that represents the photodiode feedback current in pA Notes If the CALMD CAL PD parameter is not set to 0 the LAS MDI value will not be used In this case the measured MDI would be converted to MDP Ppp by the CAL PD factor and the MDP setpoint would be used Examples Las Mdi 40 action The LASER output is controlled so that the photodiode feedback current remains constant at 40 pA Laser MDI 200 action The LASER output is controlled so that the photodiode feedback current remains constant at 200 LA LASer MDI FRONT PANEL REMOTE The LASer MDI query returns the value ofthe laser photodetector current measurement in pA Syntax Diagram Notes Examples LOPE PO where the response is the most recent LASER monitor current measurement The response is in pA The response is valid even when the unit is not in constant P mode This measurement is updated approximately once every 600 ms Las Mode MDP Las Calmd 0 Las MDi response 100 0 means 100 uA of photodetector current This feedback is controlling the laser current output LAS MODE IHBW LAS MDI response 20 0 means
44. 9 action enables the LASER status condition register so that the Open circuit and LASER current limit conditions will be summarized in the status byte bit 3 Laser Enable Cond HOF9B action enables the LASER status condition register so that any and all of the above conditions will be reported in the status byte register bit 3 LASer ENABle COND ON REMOTE The LASer ENABle COND query returns the value of the status condition enable register of the LASER operations Syntax Diagram POLY PO where the response is the sum of the following 1 LASER Current Limit 256 Output is shorted 2 LASER Voltage Limit 512 Output changed to be in out of tolerance 4 N A 1024 Output on off state 8 Power limit 2048 Ready for calibration data state 16 Interlock disabled 4096 N A 32 N A 8192 N A 64 Compliance Voltage Limit 16384 128 Open circuit 32768 N A Notes The enabled LASER conditions can be set by using the LASer ENABle COND command The LASER condition status can be monitored by the LASer COND query Examples LAS ENAB COND response 17 means that the Laser Current Limit and Interlock disabled LASER conditions will be reported in summarized form to the status byte bit 3 Radix Hex Laser Enable Cond response HOF9B means that all of the above conditions will be reported in summarized form to the status byte bit 3 01_10 LDX 3232 bb 56 LDX 3232 COMMAND REFERENCE LDX 3232 Device Depende
45. AND WARRANTY INFORMATION E SAFETY AND WARRANTY INFORMATION The Safety and Warranty Information section provides details about cautionary symbols used in the manual safety markings used on the instrument and information about the Warranty including Customer Service contact information Safety Information and the Manual Throughout this manual you will see the words Caution and Warning indicating potentially dangerous or hazardous situations that if not avoided could result in death serious or minor injury or damage to the product Specifically A CAUTION Caution indicates a potentially hazardous situation that can result in minor or moderate injury or damage to the product or equipment AJ warnino Warning indicates a potentially dangerous situation that can result in serious injury or death Z 2 WARNING Visible and or invisible laser radiation Avoid direct exposure to the beam General Safety Considerations If any of the following conditions exist or are even suspected do not use the instrument until safe operation can be verified by trained service personnel Visible damage Severe transport stress Prolonged storage under adverse conditions Failure to perform intended measurements or functions If necessary return the instrument to ILX Lightwave or authorized local ILX Lightwave distributor for service or repair to ensure that safety features are maintained see the contact information on page xiii
46. ASER limit current in mA Notes The current limit is in effect in all modes of operation ILBW IHBW or P The current limit in use depends on the LASER output range selection In local operation the limit current is entered by selecting LIM parameter pressing and holding in the PARAMETER SET switch adjusting the knob until the desired value is displayed and then releasing the SET switch Examples LAS LIM I4 1800 action the LASER current limit is set to 1800 mA Laser Limit l4 160 action the LASER current limit is set to 160 mA LASer LIMit I4 FRONT PANEL REMOTE The LASer LIMit 14 query returns the value of the LASER current limit for the 4000 mA on the LDX 3232 Syntax Diagram POP POR ox kos where the response is the current limit value for the 4000 mA range Notes The current limit is in effect in all modes of operation ILBW IHBW or P The current limit in use depends on the LASER output range selection Examples LAS LIM IA response 400 means the laser current limit is 400 mA Laser LIM I4 response 1500 means the laser current limit is 1500 mA LDX 3232 65 66 LDX 3232 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer LIMit MDP FRONT PANEL Parameters Notes Examples REMOTE The LASer LIMit MDP command sets the laser monitor photodiode power limit value Syntax Diagram lt nrf value gt lt white space gt An l
47. DI 1 Used to set the current source setpoint value LAS LDI NONE Used to return the constant current source measured value LAS LDV NONE Used to return the measured laser voltage value LAS LIM 12 1 Used to set the low range current limit LAS LIM 14 1 Used to set the high range current limit LAS LIM MDP 1 Used to set the constant optical power from monitor photodiode limit value LAS LIM V 1 Used to set the current source compliance voltage limit value LIM V LAS MDP 1 Used to set the constant optical power setpoint LAS MDP NONE Returns the actual monitor photodiode power value LAS MODE NONE Returns the mode ILBW IHBW or MDP optical power LAS MODE IHBW NONE Sets the mode to constant current high bandwidth mode LAS MODE ILBW NONE Sets the mode to constant current low bandwidth mode LAS MODE MDP NONE Sets the mode to constant optical power mode LAS OUT 1 Used to enable disable the current source output LAS OUT NONE Returns the current source output status LAS RAN 1 Sets the laser current output range 01_10 10 3232 27 28 REMOTE OPERATION Status Reporting Status Reporting LDX 3232 This section contains information that is relevant for understanding instrument error and statu reporting It also contains information regarding the use of the instrument status for generating interrupts for interrupt driven programs or subroutines Understanding the Operation Complete definition for
48. E LDX 3232 Device Dependent Command Reference LASer MODE FRONT PANEL REMOTE The LASer MODE query returns the selected laser control mode TOE poo Notes lg mode is the same as mode low bandwidth except that the output low bandpass filter is disabled in lysw mode Examples LAS MODE response ILBW means that constant current mode is in effect for the laser output Las Mode response MDP means that constant P power mode is in effect for the laser output and CALMD gt 0 Las Mode response MDI means that constant P power mode is in effect for the laser output and CALMD 0 Laser MODE response IHBW means that constant ls current high bandwidth mode is in effect for the laser output LASer MODE IHBW FRONT PANEL REMOTE The LASer MODE IHBW command selects laser high bandwidth constant current mode 0 0 Parameters None Notes This mode of operation is constant mode with the output lowpass filter disabled Examples LAS Mode Ihbw action enables the laser high bandwidth constant current mode 01 10 LDX 3232 71 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer MODE ILBW FRONT PANEL REMOTE The LASer MODE ILBW command selects laser constant current mode Parameters None Notes Constant mode low bandwidth enables the output low bandpass filter Examples LAS MODE ILBW action sets the laser output for constant mo
49. HOOTING _ Remote Calibration of the LDX 3232 Current Source Laser Forward Voltage Measurement Calibration The following procedure is for calibrating the LASER voltage measurement Configure the current source in the following manner for the laser current source voltage calibration Function State GPIB Command LASER MODE constant current low bandwidth AAS MODE ILBW RANGE 2000 mA LAS RANGE1 CURRENT LIMIT Set to FS full scale of range jAS LIM Ix I SETPOINT 400 mA AS LDI 400 a With the LASER output off connect a calibrated voltmeter in parallel with a resistor 15 Q 5 W to the LASER output Laser Anode and Laser Cathode on the rear panel of the Current Source b current source output must be on in order to enter the LDV calibration mode Enter the Enter the 1 Calibration mode LAS OUT ON command to turn the current source output on LAS CAL LDV command to place the Current Source in its LASER Voltage d Enter the measured voltage in volts via the LAS LDV nrf value command The measured value of the voltage should not be entered until the LDX 3232 Current Source is ready to receive it The current source will be ready to receive the voltage value when after a LAS CAL LDV query is sent the response from the Current Source is uq e Once the actual voltage value is entered via the LAS LDV nrf value command the Current Sou
50. Laser Current Source Calibration Current Source Calibration all models 10 Q 20 W resistor low TCR Voltage Measurement Calibration 15 Q 5 W resistor low TCR PD Monitor Calibration See Schematic in Figure 6 1 PD Calibration Circuit R1 R2 R4 R3 U1 49 Q resistor 1 1 4 W 100 Q resistor 1 1 4 W 1 0 resistor 1 1 4 W 5 O 196 10W TIL 117 opto isolator Lightwave CALIBRATION AND TROUBLESHOOTING mo 6 l Local Calibration of the LDX 3232 Current Source CHAPTER W i LD Cathode 5 LD Anode 9 PD Cathode 6 PD Anode 7 3 CALIBRATION CIRCUIT Figure 6 1 lpp Calibration Circuit Local Calibration of the LDX 3232 Current Source There are three calibration adjustments required for the LASER current source of the LDX 3232 Current Source They are calibration of the constant current source for both bandwidths and ranges calibration of the laser voltage measurement and calibration of the constant light power Ipp feedback circuits The LDX 3232 Current Source implements a two point calibration for the Laser current source Two currents approximately 80 and 20 of FS are applied to a test load and the resulting actual currents are fed back by the user to the Current Source The Laser Current Source calibration program uses the two sets of data to calculate new calibration constants These calibration constants are used to set the
51. Photodiode Current Range Oto 10 000 pA Oto 10 000 pA Photodiode Current Resolution 1 pA 1 uA Photodiode Current Accuracy 4 pA 4 pA PD Responsivity Range 0 00 to 1000 00 uA mW 0 00 to 1000 00 uA mW PD Responsivity Resolution 0 01 LA mW 0 01 uA mW Optical Power Range 0 00 to 5000 0 mW 0 00 to 5000 0 mW Optical Power Resolution 0 1 mW 0 1 mW Forward Voltage Range 0 000 to 10 000 V 0 000 to 10 000 V Forward Voltage Resolution 1 mV 1 mV Forward Voltage Accuracy 2 mV 2 mV General Size H x W x D 4 x 8 5 x 13 4 102 mm x 216 mm x 340 mm Weight 20 pounds 9 kg Power 100 120 230 240 V 2 2 1A 50 60 Hz Temperature 0 C 40 C operating 40 C 70 C storage Humidity lt 90 relative humidity non condensing Laser Safety Features Key switch interlock and output delay meets CDRH US 21 CFR 1040 10 Display Type 5 digit green LED Notes 1 All values relate to a one hour warm up period at room temperature 25 C 2 Based on resolution of digital to analog converters used in the design 3 Over any 1 hour period half scale output 4 Over any 24 hour period half scale output 5 Measured electrically with a 1 ohm load at half scale output evaluating spectral noise density over a 150kHz bandwidth from 125kHz to 275 kHz 6 Maximum output current transient from normal operational situations e g power on off current on off as well as accidental situations e g power line plug removal 7
52. R low range current source limit AS LIM IA 1 Used to set the LASER high range current source limit AS LIM 14 NONE imi AAS LIM MDP 1 Used to set the constant optical power from monitor photodiode limit value AS LIM MDP NONE Used to return the optical power from monitor photodiode limit value AS LIM V 1 Used to set the LASER compliance voltage limit value AAS LIM V NONE Used to return the LASER compliance voltage limit value LAS MDI 1 Used to set the constant optical power setpoint if photodiode responsivity is 0 LAS MDI NONE Used to return the monitor photodiode current measured value AS MDLN 1 Used to enable disable the front panel modulation input AS MDLN NONE T to return the status of the front panel modulation LAS MDP 1 Used to set the constant optical power setpoint LAS MDP NONE Returns the actual monitor photodiode power value AS MODE NONE Returns the mode current IHBW high bandwidth or P optical power AS MODE IHBW NONE Sets the mode to constant current high bandwidth AS MODE ILBW NONE Sets the mode to constant current low bandwidth AS MODE MDP NONE Sets the mode to constant optical power mode LAS OUT 1 Used to enable disable the current source output LAS OUT NONE Returns the current source output status LAS RAN 1 Sets the laser current output range LAS RAN NONE Returns the laser current output range AS SET LDI NONE Returns the laser constant current setpoint AS SET MDI NONE
53. RANge FRONT PANEL Notes Examples REMOTE The LASer RANge query returns the value of the Laser Drive Current range POPE o PE where the response is in integer 2 means 2000 mA range and 4 means 4000 mA range The resolution and accuracy of the laser limit current are dependent on the Laser Drive Current output range LAS RAN response 2 means that the Laser Drive Current range is 2000mA LAS range response 4 means that the Laser Drive Current range is 4000mA Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer SET LDI FRONT PANEL REMOTE The LASer SET LDI query returns the constant value that is used for both output ranges and both bandwidths where the response is the constant setpoint value in mA Notes In local operation the constant setpoint is read by selecting or l4gw mode then pressing and holding down the SELECT switch in the DISPLAY area of the front panel When the mA indicator is blinking the display will show the LDI setpoint Examples LAS SET LDI response 50 0 means the laser output current setpoint value is 50 0 mA Laser set ldi 120 0 means the laser output current setpoint value is 120 0 mA LASer SET MDI FRONT PANEL REMOTE The LASer SET MDI query returns the laser monitor photodiode current setpoint value when CALPD 0 in pA where the response is the constand le setpoint value in
54. SPECIFICATIONS in Chapter 1 for external analog modulation bandwidth specifications 86 LDX 3232 Lightwave 01 10 FUNCTIONS AND FEATURES Modulating the Laser Current Source Setting up the Current Source for a modulated laser injection current is easy The MOD EXTERNAL connector BNC on the front panel is the input for the modulated signal Connect a modulating voltage signal from a standard function generator for example to this connector The modulation port input impedance is 1 kO The transfer function for the low and high current ranges of the LDX 3232 are 200 mA V and 400 mA V Set the LDX 3232 in Constant Current High Bandwidth Mode by selecting lijgw in the MODE section of the front ws panel Do this by toggling the MODE SELECT push m P SELECT button until the l4gw indicator is illuminated Repeatedly m lew pressing the MODE SELECT switch cycles through the a current l optical power P or high bandwidth current odio lugw control modes RANGE aul Next set the current source range by selecting the 2000 mA range indicated by the accompanying LED You ZAN will need to press the select push button twice to change the range It must be pressed twice quickly within less than one second to switch between modes and the current 1 source output must be off MODE ON indicator unlit in PRESS TWICE order to change ranges The limit clamp function for DC output current applies to
55. The LAS LDI command does not have any fixed delay for settling With this command some trigger pulses may be missed if the program step time is less than the 20 ms minimum A one shot trigger pulse will occur on power up of the instrument due to the states of the processor I O am d _SH1 AH1 6 L4 SR1 RL1 PPO DC1 DT0 C0 E1 f Figure 5 1 LDX 3232 Rear Panel 01 10 LDX 3232 85 yes FUNCTIONS AND FEATURES CHAPTER 5 Using the LDX 3232 Current Sources s BNC Interlock Connection Using the LDX 3232 Current Sources s BNC Interlock Connection The LDX 3232 BNC interlock connection is designed to allow an external emergency input signal to turn the current output off The BNC interlock is TTL compatible and configured to be normally closed as opposed to the DB 9 interlock connection that is normally open The BNC interlock connection when left unconnected is pulled to a logic high with a 100 kO resistor High values 5 V will keep the interlock closed current source in the operational state while low values 0 V will open the BNC interlock forces the output off Once the BNC interlock is opened the output will stay off until the interlock is closed again and you re enable the output BNC Interlock Usage Example When using the LDX 3232 Current Source to drive a temperature controlled laser diode the BNC interlock can be used to accept an error signal from the laser diode temperature controller unit
56. The LASer TOLerance command allows the programmer to determine the LASER current tolerance and time window for it to occur in order that the operation complete flag be set after a LASer OUTput 1 command is issued or the LASER setpoint is changed white nrf Space value Parameters Two nrf values the first represents the LASER current tolerance in mA with a range of 0 1 to 100 0 mA and the second represents the time window in seconds with a range of 0 001 to 50 000 seconds Notes The LDX 3232 defaults to a tolerance of 1 0 mA for three seconds unless changed by the LASer TOLerance command If the LDX 3232 is operated in P mode the current tolerance parameter is not used Instead a fixed value of 50 UA is used for the lp current A fixed value of 1 mW is used for Ppp power and only the time window parameter may be adjusted Note If the tolerance is set too tight it may never be achieved This is due to the calibration of the setpoint and measurement values Examples Las Tol 0 5 10 action the LDX 3232 s LASER current source will be in tolerance when the LASER current is within 0 5 mA for 10 000 seconds 01 10 LDX 3232 77 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer TOLerance REMOTE The LASer TOLerance query allows the programmer to determine how the LASER current tolerance is set PON POMS where the response consists of two values the first is the current tolerance in
57. adjust knob to set the limit to 1 50 mW When the desired value is reached the new limit value will be stored in three seconds The LIM P is the absolute limit of optical power as detected by the unit via the monitor photodiode feedback loop In order for this limit to be meaningful the monitor photodiode responsivity CAL PD must be adjusted correctly This limit is a software limit only The LASER output is normally turned off if this limit is reached See LASer ENABle OUTOFF command in Chapter 4 for instructions on disabling this function The maximum LIM P value is 5000 0 mW Also in constant power mode the LASER current limit and voltage limit values are in effect Setting of these limits is described later in this chapter 18 LDX 3232 Lightwave OPERATION Error Indicators Mk Now the instrument is configured to operate in Constant Power Mode In the MODE section enable the output of the laser current source by depressing the OUTPUT push button once The accompanying LED labeled ON will I illuminate indicating that the laser output is on and current is on 1 being driven to the laser The LDX 3232 current source will OUTPUT drive the laser to the Constant Power setpoint and maintain closed loop control with the photodiode current measurement Error Indicators The LDX 3232 High Compliance Current Sources indicate general operational error conditions Each error condition results in an acti
58. air or service be sure to 1 Obtain a Return Authorization number RA from ILX Customer Service 2 Attach a tag to the instrument identifying the owner and indicating the required service or repair Include the instrument serial number from the rear panel of the instrument 3 Attach the anti static protective caps that were shipped with the instrument and place the instrument in a protective anti static bag 4 Place the instrument in the original packing container with at least 3 inches 7 5 cm of compressible packaging material Shipping damage is not covered by this warranty 5 Secure the packing box with fiber reinforced strapping tape or metal bands LDX 3232 xi ko ee 6 Send the instrument transportation pre paid to ILX Lightwave Clearly write the return authorization number on the outside of the box and on the shipping paperwork ILX Lightwave recommends you insure the shipment If the original shipping container is not available place your instrument in a container with at least 3 inches 7 5 cm of compressible packaging material on all sides Repairs are made and the instrument returned transportation pre paid Repairs are warranted for the remainder of the original warranty or for 90 days thatever is greater Claims for Shipping Damage When you receive the instrument inspect it immediately for any damage or shortages on the packing list If the instrument is damaged file a claim with the carrier The factor
59. at the AC power cord connection is secure power line drop outs may reset the unit and when power is restored the output will be off LDX 3232 m 99 100 LDX 3232 Troubleshooting Guide CALIBRATION AND TROUBLESHOOTING Symptom Corrective Actions Unable to adjust output Check the LIMIT parameter for the output range in use see that it is set above 0 mA Power mode operation has high output current but little or no power measured Check back panel PD BIAS if set too low may act as an open feedback loop if in doubt set the PD BIAS to mid range 2 5 V Output exceeds power limit The power limit is not a hardware limit It only serves as a warning that the power measurement has exceeded the limit setpoint Normally this limit will cause the output to shut off This feature can be defeated via the LAS ENABLE OUTOFF command Open circuit error occurs during calibration Check load connections check that measuring meter does not auto range use non auto ranging modes Calibration is aborted unintentionally Calibration modes will be aborted if an open circuit is detected VOLTAGE LIMIT indicator blinks This indicates a voltage limit error check laser connections A high impedance may cause this condition Open circuit error E503 or voltage limit error E505 prevents output from reaching desired value The LDX 3232 instruments have an adjustable laser
60. atch failed E 126 Too few or too many program data elements E 201 PROGRAM value out of range E 202 PROGRAM DATA will not convert to valid type E 203 Security violation command is not available without clearance E 205 PROGRAM DATA is not a Boolean value or word E 207 PROGRAM DATA will not convert to an unsigned 16 bit value E 209 PROGRAM DATA will not convert to an unsigned 32 bit value E 210 PROGRAM DATA will not convert to a floating point value E 211 PROGRAM DATA will not convert to a character value E 213 PROGRAM DATA is incorrect block data length E 214 PROGRAM DATA length exceeds maximum E 302 Query error device was addressed to talk but GPIB controller failed to read all of the RESPONSE MESSAGE LDX 3232 33 REMOTE OPERATION Error Messages Error Code Explanation E 501 LASER interlock disabled output E 503 LASER open circuit disabled output E 504 LASER current limit disabled output E 505 LASER voltage limit disabled output E 507 LASER power limit disabled output E 510 LASER out of tolerance disabled output E 511 LASER control error disabled output E 512 Analog section status is all 1 s or all 0 s power down E 513 Serial EEPROM checksum error E 515 Laser output must be off to change ranges E 516 Incorrect configuration for calibration sequence to start E 519 Setting a measurement is only valid durin
61. ave OPERATION Connecting to the Laser Photodiode Connections Many laser diode modules contain an internal photodiode that monitors the back facet emission of the laser Usually this photodiode is internally connected to either the laser anode or cathode The photodiode and laser connections to the LDX 3232 are electrically isolated from ground and each other So if a 4 pin connection is made no common connections no additional jumpers are required Figures 2 1 2 4 show the recommended connections and shielding for 3 pin lasers where the common connection is internal to the device A 4 pin laser should be connected with the same shielding as shown in Figure 2 1 but the common connection between the photodiode and the laser is optional Setting the PD Bias The LDX 3232 provides an adjustable reverse bias of 0 5 VDC for the photodiode To set the photodiode bias to 5 V reverse bias turn the back panel PD BIAS ADJUST fully clockwise To set the photodiode bias to 0 V reverse bias turn the back panel PD BIAS ADJUST fully counter clockwise Grounding Considerations The LASER outputs of the LDX 3232 High Compliance Current Source are isolated from chassis ground allowing either output terminal to be grounded at the user s option Figures 2 1 2 4 show the proper earth ground shielding for laser diode photodiode connections 01_10 LDX 3232 13 OPERATION Front Panel Operation Front Panel Operation Lig
62. be edited via the LAS STEP command LDX 3232 default values are 0 1 mA 0 1 mW or 1 if CALMD 0 The minimum time to complete one decrement is about 20 ms Examples LAS MODE I LAS STEP 3 LAS DEC action The laser source current setpoint is decremented by 0 3 mA LASer DISplay REMOTE The LASer DISplay command enables or disables turns off the display and some LEDs Syntax Diagram Parameters nrf value where 1 on 0 off Notes Turning the display and LEDs off means that a message of all blank spaces is sent to the display and most of the LEDs will be turned off Examples las dis 1 action turns the LASER display on and enables the LASER indicator LEDs Laser dis Off action turns the LASER display and disables the LASER indicator LEDs LDX 3232 47 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer DISplay REMOTE The LASer DISplay query returns the value shown on the display Syntax Diagram Notes Returns the actual 6 character string from the output buffer to the display If the display is disabled it returns Examples LAS DIS response 99 9 means the LASER display shows 99 9 Laser DISp response 0 6 means the LASER display shows 0 6 LASer DISplay LDI FRONT PANEL REMOTE The LASer DISplay LDI command sets the laser display to show the constant current measurement Syntax Diagram Q Parameters None Notes
63. chnician access to the protected user data command PUD that is a common command This data is normally changed only at the factor and therefore the SECURE command is not needed by the user TERM Parameters Notes Examples 80 LDX 3232 REMOTE The TERM command allows the programmer to change the default GPIB IEEE488 standard terminator to include the carriage return white lt nrf space gt value gt An nrf value O FALSE non zero TRUE An altered terminator will be in the form CR 2 NL END This technically takes the LDX 3232 out of GPIB IEEE488 specification but may be done for convenience when using non standard GPIB controllers This termination will be sent with all output until the TERM 0 command is sent or the LDX 3232 is powered off Term 1 temporarily sets lt CR gt lt NL gt lt END gt as the output terminator Term 0 sets the GPIB IEEE488 standard NL END terminator This is the LDX 3232 default value Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference TERM FRON REMOTE The TERM query allows the programmer to determine whether the default IEEE488 2 standard terminator has been altered to include a carriage return Ope where the response is 0 or 1 Notes An altered terminator will be in the form CR NL END This termination will be sent with all output until the TERM 0 command is sent or the LDX 3232 is powered
64. d is useful for creating delays that don t require a lot of program code and don t tie up the GPIB during execution The delay time is approximate with an error of about 10 Examples DELAY 500 action Further commands and queries are not executed until about 0 5 seconds have elapsed from the time this command is executed LAS LDI 22 Delay 2000 LAS LDI actions The current is set to 22 0 mA then the LDX 3232 High Compliance Current Source waits for about 2 0 seconds before returning the measured current Note Care should be taken to set the GPIB time out appropriately for use with the Delay command Lightwave 01 10 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference ERRors REMOTE The ERRors query returns a list of command and device errors that have occurred since the last query These errors are notated by a number that corresponds to the type of error that occurred See Chapter 3 for information regarding error handling Syntax Diagram Ore Pro Parameters None Notes The response data will be a list of the current errors The errors are represented by numbers and are separated by commas A response of 0 indicates that no errors were reported The response data is sent as character data Up to 10 error codes are stored between error queries Examples ERR response 0 means no errors reported Errors response 201 means that the PROGRAM DATA parameter value out of range
65. de low bandwidth LASer MODE MDP FRONT PANEL REMOTE The LASer MODE MDP command selects laser constant power mode COPE POMC Parameters None Notes This mode of laser operation requires the laser s monitor photodiode feedback to maintain constant optical power or constant monitor current In this mode the displayed parameter will be either lpp if CALMD 0 in pA or Pop if CALMD 0 in mW Examples LAS MODE MDP action sets the laser output mode of operation to constant optical power mode 72 m LDX 3232 Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer OUT put FRONT PANEL REMOTE The LASer OUTput command turns the laser output on or off white nrf Space value Parameters nrf value 1 on O off Notes There is a two second delay after the output is turned on before the output shorting relay is opened Following this the output current ramps up to the current setpoint slowly to protect the laser Therefore the time to turn the output on and reach the setpoint current varies from two to about three seconds After the output is turned on it may be useful to wait until the output is stable within tolerance before performing further operations but it is not necessary When the LASER output is off it is safe to connect or disconnect devices to the LASER output terminals When the LASER output is off an internal short is placed across the output ter
66. e Mode to Iypw high bandwidth constant current mode Repeat the calibration procedure as described above k Change the output range to high range and repeat the calibration procedure as described above lpp Current Calibration The following procedure is for calibrating the LASER lpp PD monitor setpoint and measurement This procedure calibrates the feedback circuits for constant lpp and constant Ppp modes When these values are reached and are stable the user enters the actual value of the monitor current measured with a DMM The 92 LDX 3232 Lightwave 01 10 CALIBRATION AND TROUBLESHOOTING Local Calibration of the LDX 3232 Current Source LDX 3232 Series Current Source then automatically calibrates the LASER feedback circuits Configure the Current Source in the following manner for the Laser Current Source calibration Function State MODE P constant power CAL PD set equal to zero CURRENT LIMIT 9096 of FS full scale of range Ipp SETPOINT 80 of FS a With the LASER output off connect a calibrated ammeter to the PD Anode output of the Laser Current Source output connector 9 pin on rear panel and connect the circuit of Figure 6 1 to the LASER and PD outputs with the correct load resistor for the Current Source model you are calibrating See Table 6 2 Note If a precision ammeter is not available use a zero Ohm jumper in place of the ammeter Then place a calibrated
67. e gt Syntax Diagram Parameters nrf value that represents the LASER limit voltage in volts Notes The voltage limit setting is useful for laser protection When the maximum operating voltage of a laser is known the user may set the voltage limit to a value slightly higher than the maximum operating voltage Then if the laser is accidentally disconnected the current source will quickly sense the over voltage and shut off In local operation the voltage limit is entered by selecting the COMP V parameter pressing and holding in the PARAMETER SET switch Turn the adjust knob until the desired value is displayed and then release the SET switch Examples LAS LIM V 5 0 action the LASER compliance voltage limit is set to 5 0 V Laser Limit V 4 60 action the LASER compliance voltage limit is set to 4 6 V LASer LIMit V FRONT PANEL REMOTE The LASer LIMit V query returns the value of the LASER compliance voltage limit setting Syntax Diagram LOPE POPOL 9o where the response is the LASER limit voltage setpoint Notes The voltage limit is valid for all modes of Laser operation In local operation the voltage limit is seen by selecting the COMP V parameter pressing and holding in the PARAMETER SELECT switch Examples LAS LIM V response 4 5 means the laser compliance voltage limit is 4 5 V Laser LIM V response 10 0 means the laser compliance voltage limit is set to 10 0 V 01 10 LDX 3232
68. e verification indicates that calibration is necessary such as differences between setpoint and measurement display values that exceed the accuracy specification Calibrate the instrument under laboratory conditions We recommend calibration at 23 C 1 0 C When necessary however the LDX 3232 Current Source may be calibrated at its intended use temperature if this is within the specified operating temperature range of 0 to 40 C LDX 3232 89 90 CALIBRATION AND TROUBLESHOOTING Recommended Equipment Finally the LDX 3232 Current Source should be allowed to warm up for at least one hour before calibration Recommended Equipment LDX 3232 Recommended test equipment for calibrating the LDX 3232 Current Source is listed in Table 6 1 Equipment other than that shown in the table may be used if the specifications meet or exceed those listed Table 6 1 Recommended Test Equipment Description Manufacturer Model Specification DMM HP 3457A DC Amps 1 0 A 0 02 Resistance 10 0 02 0 1 or 0 1 mV resolution It will be necessary to connect various loads and circuits to the outputs of each current source for the calibration procedure A schematic is shown in Figure 6 1 for the photodiode calibration circuit with the required components listed in Table 6 2 Also the devices required for other calibration loads are listed in Table 6 2 Table 6 2 Required Calibration Components
69. er the laser voltage calibration mode LAS CAL LDV NONE Returns the ready state for entering the laser voltage calibration mode LAS CAL MDI NONE sse to enter the monitor photodiode current calibration mode 01 10 LDX 3232 35 36 E LDX 3232 4 COMMAND REFERENCE Name Parameters Function LAS CAL MDI NONE Returns the ready state for entering the monitor photodiode current calibration value LAS COND NONE Returns the value of the LASER condition register AAS DEC 0 Used to decrease the laser current setpoint value by one step LAS DIS 1 Turns the LASER display on or off LAS DIS NONE Returns the LASER display value LAS DIS LDI NONE Turn on off LASER display to show laser output current LAS DIS LDI NONE Returns status of laser output current display on off LAS DIS LDV NONE Turn on off LASER display to show laser output voltage LAS DIS LDV NONE Returns status of laser output voltage display on off LAS DIS MDI NONE Turn on off LASER display to show photodiode monitor current LAS DIS MDI NONE Returns status of photo diode monitor current display on off LAS DIS MDP NONE Turns on off LASER display to show photodiode monitor power LAS DIS MDP NONE Returns status of photodiode monitor power display on off LAS DIS
70. eration use the command RCL x where x is the desired bin number 0 10 Using the Laser Compliance Voltage Adjustment For applications where you need to have critical protection of the laser we recommend the following Using a 1 Q resistor or other non critical load set the LASER voltage limit as described in Chapter 2 Then with the LASER output on slowly increase the LASER current and watch the LASER voltage measurement Press the DISPLAY SELECT push button to see the voltage At about 0 25 V below the LASER voltage limit value the VOLTAGE LIMIT warning indicator will become lit on the display Continue to adjust the current upwards until the voltage limit is reached and the output is shut off Record the voltage at that the LASER output shuts off It should be within the specification of the LASER voltage limit accuracy However there is typically some offset error For example if the LASER voltage limit is set to 5 0 V the actual voltage where it shuts off may be 4 9 V This error term of 0 1 V should be considered when setting the LASER compliance voltage limit The closer the LASER voltage limit shut off point is to the operating voltage of your laser the faster the circuit will work in the event of an open circuit Some experimentation may be necessary for optimum results 84 LDX 3232 Lightwave FUNCTIONS AND FEATURES Using the LDX 3232 Current Source s Trigger Function Using the LDX 3232 Current Source
71. error was reported since the last ERR query LASer CALMD FRONT PANEL REMOTE The LASer CALMD command sets the laser s photodiode feedback responsivity the CAL PD parameter Syntax Diagram lt white space gt nrf value Parameters nrf value in mA mW The range is 0 to 1000 Notes If the parameter is set to 0 the LDX 3232 will operate in a constant lpp mode when Constant P MDP mode is selected The parameter should be set to 0 for lpp operation modes Otherwise the value of this parameter is used to convert between lp and P values The units of this parameter are mA mW Examples LAS CALMD 0 action sets the CAL PD parameter to 0 This enables the constant lpo mode of operation Laser Calmd 1 action sets the CAL PD parameter to 1 00 mA mW Therefore a photodiode feedback current of 1 mA will cause the Pp display to read 1 mW LDX 3232 41 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer CALMD FRONT PANEL REMOTE The LASer CALMD query returns the value of the laser s photodiode feedback responsivity CAL PD parameter setting Syntax Diagram PON HO lt Pe Notes If this value is 0 the LDX 3232 will be set to operate in constant lpp mode and the lpo setpoint value will be in effect If this value is non zero the LDX 3232 will be set to operate in constant Pa mode and the setpoint value will be in effect If this value is 0 the fro
72. etters are shown in upper case lower case letters are optional Front Panel Remote Execution Front Panel A solid box means the command LASer LIMit Il can be executed in that mode Command mnemonics in front panel local mode may vary The LASer LIMit I2 command sets the laser current Pd limit value Command Description SYNTAX DIAGRAM W Remote Syntax Diagram For Remote Commands Parameters Tells what parameters are nrf value gt expected and their type An nrf value refers to a flexible numeric notation IEEE 488 2 Integer exponential or floating point may be used with the decimal radix Alternate radices may be selected in remote operation POINTS An lt nrf value gt that represents the LASER limit current in mA The current limit is in effect in all modes of m un INTEREST operation of the laser output Points of Interest In local operation the limit current is entered Has special information by selecting the LIM I parameter pressing and about the command holding in the PARAMETER SET switch adjusting the ADJUST knob until the desired value is displayed and then releasing the SET switch Examples Shows typical statements using the command Las Lim D2 100 action the LASER current limit is set to 100 0 mA LAS LIM IA 3000 action the LASER current limit is set to 3000 0 mA Figure 4 1 Command Description Format LDX
73. formed at the current setpoint wherever it is set If the LASER output is not on E516 is displayed In remote operation the LASer CAL LDI query may be used to determine if the LDX 3232 High Compliance Current Source is ready for the user to enter a value Examples Las CAL Ldl action the LDX 3232 enters calibration mode for LASER current Las Cal LDI action the LDX 3232 enters calibration mode for LASER current 01_10 LDX 3232 43 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer CAL LDI FRONT PANEL REMOTE The LASer CAL LDI query is used to determine that the LDX 3232 is ready for a value to be entered during the calibration cycle of the LASer CAL LDI mode Syntax Diagram POX PO Notes After this query is issued and a response of 1 is received the LDX 3232 will be ready for the user to enter a current value via the LASer LDI command see Chapter 6 Examples LASer CAL LDI response 1 means the LDX 3232 is ready for the user to enter a current value via the LASer LDI command LASer Cal Ldl response 0 means the LDX 3232 is not yet ready for the user to enter a LASER current value LASer CAL LDV FRONT PANEL REMOTE The LASer CAL LDV command is used to enter the LASER voltage measurement calibration mode Syntax Diagram Parameters Notes Examples 44 LDX 3232 None After this command is issued the LDX 3232 will allow calibration of the laser vol
74. g the calibration phase for that measurement ma la tried to calibrate a measurement without first entering the required calibration 34 m LDX 3232 Lightwave H a a CHAPTER COMMAND REFERENCE El El mH a El El m Fi a This chapter is a guide to all of the device dependent commands for the LDX 3232 High Compliance Current Source This chapter is divided into two parts The first part contains an overview of the remote commands used by the LDX 3232 High Compliance Current Source The second part contains all of the LDX 3232 commands in alphabetical order Figure 4 1 shows the format for the device command descriptions in this chapter The commands that emulate local front panel operation are denoted by the solid box next to the Local label in the upper left corner of the command description Table 4 1 LDX 3232 Series Device Dependent Commands Name Parameters Function DELAY 1 Used to create a delay in the execution of further commands ERR NONE Returns errors generated since the last query AS CALMD 1 Used to set the CAL PD monitor responsivity constant LAS CALMD NONE Returns the CAL PD monitor responsivity constant LAS CAL CONST 1 Factory use only LAS CAL LDI NONE Used to enter the laser current calibration mode LAS CAL LDI NONE Returns the ready state for entering the laser current calibration value LAS CAL LDV NONE Used to ent
75. he LDX 3232 s GPIB address locally via front panel A procedure for changing the address can be found in the section Changing the GPIB Address in Chapter 3 Tilt Foot Adjustment The LDX 3232 High Compliance Current Source comes standard with folding front legs and two rear feet for use as a bench top instrument Extending the front feet so that the instrument front panel sits up makes it easier to view the LED displays To use them place the unit on a stable base and rotate the front legs downward until they lock into position Operating the LDX 3232 Precision Current Source Now that the LDX 3232 High Compliance Current Source is installed and ready for use you can begin to learn about its operation The following photos show the functional keypad groupings back panel connectors and so on Use these figures to familiarize yourself with the LDX 3232 After that use Chapter 2 for fundamentals of operating your instrument 01_10 LDX 3232 3 INTRODUCTION AND SPECIFICATIONS _ Installing Your LDX 3232 High Compliance Current Source Adjust Section Display j ILX Lightwave 232 HIGH COMPLIANCE LASER DIODE CURRENT SOUCI INTERLOCK VOLTAGE LIMIT CURRENT LIMIT OPEN CIRCUIT POWER LIMIT SELECT Power PARAMETER Switch o mi A me 7 CALPD COMPV LJ SET GPIB Section Parameter Laser Mode Current Range Modulation Input Selection Selection Selection Connector Figure 1 1 LDX 3232 Front View
76. he CAL PD parameter set to zero S When the CAL PD value is zero the LASER output will be m P SELECT controlled to the lpp setpoint value Therefore the m iew instrument is in Constant mode The display will indicate for the power measurement Next configure the display so that it reads in mW by pressing and releasing the DISPLAY SELECT switch until the mW annunciator is lit Adjust the Constant Power setpoint of the LDX 3232 to 1 00 mW To do this turn the adjust knob to vary the setpoint When the adjust knob is turned the LDX 3232 automatically changes to setpoint mode as indicated by the flashing annunciator Adjust the setpoint to 1 00 mW After an adjustment has been made and the adjust knob is released the setpoint mode will time out in three seconds The display will then return to the measurement display mode 1 Ipp V or Ppp Before the laser output is enabled the power limit for the laser under test should be set In Constant Power mode this is accomplished by setting a Power limit LIM P value The LDX 3232 uses the responsivity value entered to calculate a power limit as a function of monitor current Ipp This is a software limit only To set the Constant Power limit use the SELECT push button in the PARAMETER section to select LIM P When the LIM P is indicated by the accompanying LED the display will indicate the limit setpoint in mW Press the PARAMETER SET push button and rotate the
77. he GPIB 55 21 Changing Operation from Local to Remote 22 LDX 3232 Current Source Command Set 22 Command Syntax iussa dox wee 22 Command Paths 25 IEEE488 2 Command Commands 26 LDX 3232 Frequently Used Commands 27 Status Reporting 28 Event and Condition Registers 28 Operation Complete Definition 28 Output Off Register 2 eh 30 Command Timing and Completion 32 Error Messages oec Ree tg cu Ro ec cg c ed 32 ii LDX 3232 Lightwave Chapter 4 Command Reference LDX 3232 Device Dependent Commands 39 LDX 3232 Device Dependent Command Reference 40 Chapter 5 Functions and Features Saving and Recalling from the Front Panel 83 Saving and Recalling Under Remote Operation 84 Using the Laser Compliance Voltage Adjustment 84 Using the LDX 3232 Current Source s Trigger Function 85 Using the LDX 3232 Current Sources s BNC Interlock Connection 86 BNC Interlock
78. htwave 0x 3232 HIGH COMPLIANCE LASER DIODE CURRENT SOURCE PD INTERLOCK VOLTAGE LIMIT CURRENT LIMIT E OPEN CIRCUIT POWER LIMIT SELECT This section describes fundamentals of operation for your LDX 3232 in two operating modes Constant Current l and Constant Power P The Display The digital display is used to show control parameters such as laser drive current mA laser current limit mA laser forward voltage V voltage limit V monitor photodiode current uA and laser optical power mW in both setpoint and measurement modes It will also display error codes that relate to LASER operation Error indicators underneath the display indicate control errors and are explained in the section titled ERROR INDICATORS All laser control parameters are displayed on this digital display with the appropriate annunciator illuminated Operating a Laser in Constant Current l Mode Suppose you have an LDX 3232 and you want to run the instrument in Constant Current low bandwidth mode with a setpoint of 1500 mA and a current limit of 1750 mA This particular mode uses a low pass filter on the laser drive current output to significantly reduce noise In this mode a modulation input of up to 10 kHz may be used via the front panel MOD EXTERNAL connector Follow the instructions below in the sequence presented 14 LDX 3232 Lightwave 01 10 OPERATION Operating a in Constant Current 1 Mode Setting Up the
79. ideas and comments on ways we can improve out products We invite you to contact us at any time with your suggestions 8 m LDX 3232 uix Lightwave CHAPTER 2 OPERATION a El m a a m H El El a El El a mn a This chapter introduces you to the operation of the LDX 3232 High Compliance Current Source It offers instructions for connecting your laser to the current source and describes powering up the instrument This chapter also contains step by step procedures that teach you how to operate your current source in Constant Current Mode and Constant Power Mode We recommend that you review the contents of this chapter at a minimum before operating the LDX 3232 Current Source Applying Power to Your LDX 3232 To turn on the LDX 3232 rotate the key in the POWER section of the front panel from O to I This action will initiate the power on sequence If the LDX 3232 does not appear to turn on verify that it is connected to line power If line power is not the problem remove the power cord and check the voltage selection block in addition to the line power fuse The Power On Sequence During the power up sequence the following takes place For about three seconds all indicators light up and all of the 7 segment displays indicate 8 Then all lamps are turned off for three seconds Next the firmware version will be displayed Then a self test is performed to ensure that the instrument s hardware and processor are communicati
80. inated when the instrument is communicating over the GPIB bus For more information on low level interface commands such as LLO refer to the IEEE488 1 specification LDX 3232 Current Source Command Set LDX 3232 For the most efficient and effective remote control of your LDX 3232 High Compliance Current Source we recommend you study the following sections You will learn about the LDX 3232 command sets both GPIB IEEE488 Command Commands and the most used device specific commands and command syntax Later in this chapter you will be introduced to the error and status registers Command Syntax Any command or command query must contain all of the letters that are shown in the LDX 3232 Command Path Structure Figure 3 2 However the Current Source s command parser is NOT CASE SENSITIVE so upper or lower case may be used in any combination The lower case letters shown with the Device Dependent commands in Chapter 4 are optional letters and may be used for clarity For example the following commands are equal LAS DIS 1 LAS DisP 1 LAS DISPLAY 1 In this example only the first three letters DIS are required while the other letters play are optional These optional letters must be used in the proper sequence as shown Lightwave REMOTE OPERATION LDX 3232 Current Source Command Set The syntax of the LDX 3232 High Compliance Current Source commands follows the rules laid out in the GPIB IEEE488 sta
81. is outlined in Chapter 6 If the LASER output is not ON or if the P mode is not selected error code E 516 will be generated In remote operation the LASer CAL MDI query may be used to determine if the LDX 3232 is ready for the user to enter a value via the LASer MDI command Examples Las CAL MDI action the LDX 3232 enters the LASER photodiode current calibration mode LAS Cal MDI action the LDX 3232 enters the LASER photodiode current calibration mode LDX 3232 45 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer CAL MDI FRONT PANEL REMOTE The LASer CAL MDI query is used to determine that the LDX 3232 is ready for a value to be entered during the calibration cycle of the LASer CAL MDI mode Syntax Diagram POLE PO After this query is issued and a response of 1 is received the LDX 3232 be ready for the Notes user to enter a photodiode current value via the LASer MDI command see Chapter 6 Examples LAS CAL MDI response 1 means the LDX 3232 is ready for the user to enter a photodiode current value via the LASer MDI command LASer COND REMOTE The LASer COND query returns the value of the status condition register of the LASER operations Syntax Diagram A N 64 128 Notes 46 LDX 3232 eor poe where the response is the sum of the following LASER Current Limit 256 LASER Voltage Limit 512 N A 1024 Power limit 2048 Interlock disabled
82. isters These bits are then logically ORed to form a summary message in the status byte for that particular register Operation Complete Definition Note that Bit 0 of the Standard Event Status Register contains the status of the Operation Complete flag Enabling this bit via the ESE command allows the user to update bit 5 of the status byte Then if the SRE mask has bit 5 set and the user issues an OPC command the SRQ bus signal will be generated upon completion of the currently processed commands This bus signal SRQ may be used to initiate service request routines that depend on the completion of all previous commands Lightwave REMOTE OPERATION Status Reporting For example the user may turn the current source on LAS OUT 1 enable an SRQ on Operation Complete set ESE 1 and SRE 5 and have an SRQ handling routine in the user s software that reads a new measurement after the output on state has been reached This allows the use of the operation complete features of the LDX 3232 without the need for program looping or polling that can tie up the GPIB Operation Complete on the LDX 3232 is defined as 1 No operations to the LASER current source hardware are pending 2 No EEPROM non volatile memory write cycles are in progress Standard TASER Condition Status Register Event Status Register
83. it disabled output E 504 LASER current limit disabled output E 505 LASER voltage limit disabled output E 507 LASER power limit disabled output E 510 LASER out of tolerance disabled output E 511 LASER control error disabled output E 512 Analog section status is all 1 s or all 0 s power down E 513 Serial EEPROM checksum error E 515 Laser output must be off to change ranges E 516 Incorrect configuration for calibration sequence to start E 519 Setting a measurement is only valid during the calibration phase for that measurement Rm tried to calibrate a measurement without first entering the required calibration 102 LDX 3232 Lightwave
84. mA and the second is the time window in seconds Notes The tolerance of the LDX 3232 LASER current may be used to delay programming after an LASer OUTput 1 command is issued or the setpoint is changed A change of the output into or out of tolerance flag sets a flag in the LASER status event register and so entering or exiting LASER current tolerance may be used to generate service requests Examples Las Tol response 0 2 5 0 means the LDX 3232 has a LASER current tolerance setting of 0 2 mA with a time window of 5 000 seconds LASER TOL response 1 0 20 0 means the LDX 3232 has a LASER current tolerance setting of 1 0 mA with a time window of 20 000 seconds MESsage REMOTE The MESsage command allows the user to enter an ASCII string of up to 16 non NULL characters This command may be useful for storing messages that relate to a test or configuration lt white Jesi space gt string gt Parameters An ASCII string that is 1 16 bytes in length Notes The message may contain any ASCII character but will be terminated when a NULL terminator character is received If the message has less than 16 bytes the software will fill the remaining message space with the space character After 16 bytes have been entered the software will null terminate the string Examples MESSAGE This is a test action The string This is a test will be stored in non volatile memory Mes Test 3 action The string Test 3 will be s
85. minals Examples LAS I 20 LAS OUT ON action sets the laser output current to 20 mA and then turns the output on LASer OUTput FRONT PANEL REMOTE The LASer OUTput query returns the status of the laser output switch 0 e where the response is 0 or 1 Notes Although the status of the switch is on the output may not have reached the setpoint value Examples Las OUT response 0 means that the output switch is disabled devices may be safely disconnected or connected at the LASER output terminals LAS OUT response 1 means that the LASER output switch is enabled LASER output is present 01_10 LDX 3232 73 74 LDX 3232 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer RANge FRONT PANEL REMOTE The LASer RANge command selects the laser s drive current output range Parameters Notes Examples An lt nrf value that represents the laser current output range 2 2000 mA and 4 4000 mA range This range setting effects the Laser Drive Current output current range only The Laser Drive Current output should be off when this command is issued If the Laser Diode Current output is on when this command is issued the LDX 3232 will generate error E515 and the range will not be changed LAS RAN 4 action sets the laser output drive current range to 4000 mA Laser range 2 action sets the laser output drive current range to 2000 mA LASer
86. ndard Colons indicate the start of a new command path while semicolons indicate a separation of commands within a command string A leading colon on a command may be used to return the LDX 3232 High Compliance Current Source command parser to the command path root see Figure 3 1 Spaces or white space may be used to separate commands and or data after the command header or query question mark Spaces or white space must be used to separate the command header from the first parameter or program data The following examples show valid syntax for commands with the LDX 3232 High Compliance Current Source e LAS display ldi e Laser limit ldi 400 e LAS DIS 1 las set ldi Las MODE Mdp LAS OUT 1 The following are examples of invalid syntax for the LDX 3232 High Compliance Current Source These command strings would produce an erroneous result as explained AS MODE MDP Missing colon MODE expected AS MODE ILBW DEC Missing semicolon DEC command generates an error LAS DIS Space not allowed before question mark DIS command expected Las LDI33 dis Space missing between LDI command and the parameter value 33 For further clarity in programming the Boolean values of one 1 and zero 0 may be used or their names as indicated in the following table Table 3 1 Substitute Parameter Names Substitute Name Value ON 1 OFF 0 OLD 1 NEW 0 TRUE 1
87. ng After this test the instrument is ready to operate and is configured to the state it was in when the power was last shut off 01_10 LDX 3232 9 10 OPERATION Connecting to the Laser The Power On State You can choose to clear the last saved state by recalling the default values These values are stored in BINS to that you can save or recall instrument configurations described in more detail in Chapter 5 BIN O contains all of the default configurations listed in Table 2 1 Note If the instrument cannot successfully complete the power on test an error message of E 512 or E 513 will be displayed on the Display See Chapter 3 for a list of error codes and actions to take when your instrument indicates these errors Table 2 1 LDX 3232 Default Settings GPIB mode in LOCAL via front panel or in REMOTE via GPIB PARAMETERS not selected CAL PD 0 pA mW LIM I high range 1000 mA LIM I low range 500 mA LIM V 15 volts LIM P 5000 mW Output off DISPLAY enabled in mode Constant low bandwidth mode selected setpoint 0 mA lpp setpoint 0 pA Ppp setpoint 0 mW RECALL BIN number 0 Connecting to the Laser LDX 3232 When connecting your laser to the LDX 3232 we recommend that the instrument be powered up with the output off In this condition a low impedance shunt is active across the output terminals When disconnecting devices it is
88. nt Calibration The following procedure is for calibration the LASER Ipp constant current source This procedure calibrates the feedback circuits for constant and constant Ppp modes When these values are reached and are stable the user enters the actual value of the current as measured by an external DMM The LDX 3232 Current Source then automatically calibrates the LASER feedback circuits Lightwave CALIBRATION AND TROUBLESHOOTING Remote Calibration of the LDX 3232 Current Source Configure the current source in the following manner for the laser current source calibration Function State GPIB COMMAND LASER MODE constant current low bandwidth AS MODE ILBW RANGE Low lowest per instrument model LAS RAN x LIMIT 90 of FS full scale of range LAS LIM Ix Ipp SETPOINT 80 of FS LAS LDI a With the LASER output off connect a calibrated ammeter to the PD Anode output of 01 10 the Laser Current Source output connector 9 pin on rear panel and connect the circuit of Figure 6 1 to the LASER and PD outputs with the correct load resistor for the Current Source model you are calibrating See Table 6 2 Enter the LAS OUT ON command to turn the LASER output on Verify proper operation i e the IPD output should be close to the setpoint and the unit should not be in current limit read the limit status via the LAS COND query bit 0 Enter the LAS CAL MDI command to
89. nt Command Reference LASer ENABle EVEnt REMOTE The LASer ENABle EVEnt command sets the status event enable register of the LASER operations These events are summarized in bit 2 of the status byte register Syntax Diagram Parameters 1 2 4 8 16 32 64 128 Notes Examples lt white lt nrf space gt value gt An lt nrf value gt whose sum represents the bits that are enabled LASER Current Limit 256 Output is shorted LASER Voltage Limit 512 Output changed to be in out of tolerance N A 1024 Output on off state changed Power limit 2048 New measurements taken Interlock changed state 4096 N A N A 8192 N A Compliance Voltage Limit 16384 N A Open circuit 32768 N A The enabled LASER events can be read by using the LASer ENABle EVEnt query The LASER event status can be monitored by the LASer EVEnt query The enable registers normally retain their values at power up as they were at power down unless the power on status clear flag is set true for more information see the PSC definition in the GPIB IEEE488 specification LAS ENAB EVENT 136 action enables the LASER status event register so that the Open circuit and Power limit events will be reported in summarized form to the status byte bit 2 Laser Enable Event HOF9B action enables the LASER status event register so all of the above events will be reported in summarized form to the status byte bit 2 Lightwave COMMAND REFERENCE
90. nt panel Ppp will display and no Ppp value can be calculated Examples LASER CALMD response 0 means the LDX 3232 is set for operation in constant Ipp mode if P mode is also selected Las Calmd response 1 1 means the LDX 3232 is set for operation in constant Ppp mode if P mode is also selected and the responsivity is set to 1 1 pA mW 1 1 A of photodiode feedback current represents 1 mW of optical power LAS CAL CONST FRONT PANE REMOTE The LAS CAL CONST query returns a stored calibration value It is intended for factory use only 42 m LDX 3232 Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer CAL LDI FRONT PANEL REMOTE The LASer CAL LDI command is used to enter the LASER current setpoint measurement and limit in low bandwidth mode calibration mode Syntax Diagram Parameters None Notes Since the limit circuit is the same for both high and low bandwidth modes it is only calibrated when low bandwidth mode is selected After this command is issued the LDX 3232 High Compliance Current Source will allow calibration of the current setpoint measurement and limit if low bandwidth mode is selected This procedure is outlined in Chapter 6 The calibration defaults to the selected bandwidth setting Therefore it is necessary to select the desired bandwidth I or lug and turn the LASER output on before performing the calibration for that bandwidth Calibration is per
91. ntenance 5 Specifications cool sull eR tee EA RE kaka da on 6 Available Options and Accessories 8 Chapter 2 Operation Applying Power to Your 0 3232 9 The Power On Sequence 9 The Power ON SAL ened Y RE iW 10 01 10 LDX 3232 i ko m a Connecting to the Laser 10 Interlock Connections 12 Photodiode lt 13 Setting the PD Bias 1 6 rel en nn kn nn knn n anan a ann ann 13 Grounding Considerations 13 Front Panel Operation 14 The Display e ERU EE MUS bs date ee Dd ede us ped Mee 14 Operating a Laser in Constant Current l Mode 14 Setting Up the Precision Current Source 15 Conditions That Will Automatically Shut Off the LASER OUTPUT 17 Operating a Laser in Constant Power P Mode 17 Entering Photodiode Responsivity Values 17 Error Indicators ger ER URS ke CREER RR RUE Rn 19 Chapter 3 Remote Operation Reading the GPIB Address 21 Changing t
92. off Examples Term response 1 means that the CR NL END terminator is temporarily being used Term response 0 means that the lt NL gt lt END gt terminator GPIB IEEE488 standard is being used TIME ON REMOTE The TIME query allows the programmer to determine how much time has passed since the LDX 3232 was last powered up Oppo where the response is character data in the form hours minutes seconds Notes The TIME clock is independent of the TIMER clock Examples Time response 1 02 36 means that one minute and 2 36 seconds have passed since the LDX 3232 was powered up TIME response 32 00 76 means that 32 minutes and 0 76 seconds have passed since the LDX 3232 was powered up 01_10 10 3232 m 81 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference TIMER ERONTPANEI REMOTE The TIMER query allows the programmer to determine how much time has passed since the last TIMER query was issued Ore where the response is character data that represents hours minutes seconds Notes Each time the TIMER query is issued the timer is reset to 0 and the elapsed time since the last TIMER query is returned The timer counter is initially set at power up the same as the TIME counter So the first time the TIMER is issued its response will be the same as if a TIME query s response Examples Timer response 00 02 00 31 means the LDX 3232 has been on for two minutes and
93. on Complete Definition All LDX 3232 device dependent commands are executed in an overlapped manner except the DELAY command that is sequential The operation complete flag is set after the conditions outlined in the Operation Complete Definition have been satisfied The WAI common command is an example of a sequential command that forces the next command to wait until the no operation pending flag is true This is essentially the same as waiting for the OPC flag to become true because the no operations pending flag is used to set the OPC flag bit O of the Standard Event Status Register Commands that change the status of the instrument limits or change its mode or current range step value or status enable registers will not have their OPC flag set until all current writing to non volatile memory has been completed This is done to ensure that the OPC flag is never set prematurely Whenever there is any output response data in the Output Queue bit 4 is set in the Status Byte Register Whenever there is any error message in the Error Queue bit 7 is set in the Status Byte Register Error Messages In the event of a hardware error condition error messages will be displayed on the display In most cases the error message will appear for three seconds In some cases the error code display will remain until the user changes display modes In the case of multiple error messages the display may sequentially show each message fo
94. on as shown in the table below Table 2 2 LDX 3232 Error Indicators Error Condition Action Interlock Output off INTERLOCK light flashes at 1 Hz Open Circuit Output off OPEN CIRCUIT light flashes at 1 Hz if this condition was caused by an excessively high compliance voltage the VOLTAGE LIMIT light will also be turned on Current Limit CURRENT LIMIT light flashes at 1 Hz Voltage Limit VOLTAGE LIMIT light flashes at 1 Hz this indicator warns that the output is within 0 25 V of LIM V setting if the voltage limit LIM V is reached the LASER output will shut off Optical Output Output off POWER LIMIT light flashes at 1 Hz Power Limit 01_10 LDX 3232 19 OPERATION Error Indicators 20 LDX 3232 uix Lightwave 01 10 CHAPTER 3 REMOTE OPERATION m El Bl a a a uH El El Ha a a E a a A a Everything you learned to do from the front panel can also be done remotely and in some cases with more flexibility For instance in remote mode you have access to commands for functions not found on the front panel such as commands that will increment INC and decrement DEC the current setpoint by a pre defined step value The following sections show you the fundamentals of operating your LDX 3232 High Compliance Current Source remotely through the GPIB interface Reading the GPIB Address Before you can operate the LDX 3232 instrument from a remote location you need to know its GPIB address Simpl
95. pendent Command Reference LASer LIMit I2 FRONT PANEL REMOTE The LASer LIMit I2 command sets the LASER current limit value for the 2000 mA range on the LDX 3232 Syntax Diagram Parameters nrf value that represents the LASER limit current in mA Notes The current limit is in effect in all modes of operation ILBW IHBW or P The current limit in use depends on the LASER output range selection Examples LAS LIM I2 180 action the LASER current limit is set to 180 mA Laser Limit l2 160 action the LASER current limit is set to 160 mA LASer LIMit I2 FRONT PANEL REMOTE The LASer LIMit I2 query returns the value of the LASER current limit for the 2000 mA range on the LDX 3232 Syntax Diagram PON POPOL PE where the response is the current limit value for the 2000 mA range Notes The current limit is in effect in all modes of operation ILBW IHBW or P The current limit in use depends on the LASER output range selection Examples LAS LIM I2 response 40 means the laser current limit is 40 mA Laser LIM I2 response 50 means the laser current limit is 50 mA 64 m LDX 3232 Lightwave 01 10 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer LIMit I4 FRONT PANEL REMOTE The LASer LIMit l4 command sets the LASER current limit value for the 4000 mA range on the LDX 3232 Syntax Diagram Parameters nrf value that represents the L
96. quest Service Master Status Summary ei 7P lt 5 4 3 2 1 0 7 Error Available Service Request Enable Register 8 Output Shorted 9 Tolerance Change 10 Output On Off change 11 New Measurement Ready 12 SRE fis fis fe Ju fo 9 8 7 6 5 4 3 2 1 0 13 QUEUE SRE 14 NA NOT EMPTY TASER Event Status Enabe 15 NA IAS ENABE Event ERROR IAS ENZBE QUEUE Figure 3 2 LDX 3232 Status Reporting Schematic Diagram Note If the GPIB times out while waiting for a response either set the GPIB time our longer or use SRQ generated interrupts in your program See your GPIB manual for time out configuration or SRQ programming setup The OPC OPC and WAI commands should not be used inside a calibration routine 01 10 LDX 3232 29 30 LDX 3232 REMOTE OPERATION 0 Reporting Output Off Register The Output Off Enable Register allows you to determine that conditions and events in the LDX 3232 High Compliance Current Source can cause the current source output to be turned off This reigster is configured in a manner similar to the status reporting registers However the register output is not reported in the Status Byte Register Rather it sets the hardware that controls the output switching The events and conditions that may be set to cause the current source output to be turned off are shown in Figure 3 3
97. r three seconds In addition to the hardware errors GPIB errors may be read via the ERR query Table 3 4 lists the numerical error ranges by function Table 3 5 contains all of the error messages that may be generated Not all of these messages may appear on the front panel displays Some refer to GPIB activities only In remote operation the errors can be read by issuing the ERR query When this is done all of the error messages that are resident in the error queue are returned Lightwave 01 10 REMOTE OPERATION NOD Error Messages CHAPTER up to 10 may be stored Reading the error queue via GPIB clears the error queue Table 3 4 Erro r Code Classifications Error Code Range Area of Operation E 001 to E 099 Internal Program Errors E 100 to E 199 Parser Errors E 200 to E 299 Execution Control Errors E 300 to E 399 GPIB Errors E 500 to E 599 LASER Control Errors Table 3 5 LDX 3232 Series Error Codes Error Code Explanation E 001 Memory allocation failure E 103 DEFINITE LENGTH ARBITRARY BLOCK PROGRAM length too long E 104 NON DECIMAL NUMERIC PROGRAM DATA type not defined E 105 DECIMAL PROGRAM DATA exponent not valid E 106 DECIMAL PROGRAM digit expected E 123 Command not found E 124 program mnemonic Lookup failed because query command type m
98. rce will set the current to approximately one fourth 1 4 of the original value It will then expect the second calibration voltage point f Input the second actual measured LASER forward voltage as an nrf value as in Step d g Once the second actual voltage value is entered via the LAS LDV command the Current Source will store the new calibration constants The oPC query may be used after the LAS LDV value is sent to determine when the calibration is completed Or wait about two seconds before continuing with other GPIB command S Lightwave CALIBRATION AND TROUBLESHOOTING Troubleshooting Guide Troubleshooting Guide This section is a guide to troubleshooting the LDX 3232 Current Sources Some of the more common symptoms are listed here and the appropriate troubleshooting actions are given We recommend that the user start at the beginning of this guide Read the symptom descriptions and follow the steps for the corrective actions that apply If you encounter problems that are beyond the scope of this guide contact your ILX Lightwave customer service representative Symptom Corrective Actions GENERAL LDX 3232 unit will not power up Check AC power line voltage and power cord connection Power on but display is frozen and switches don t operate This may occur if the instrument loses power AC line briefly turn the power switch off and on again to restart Display
99. recent laser current measurement Notes Response is the measured laser output current for either low or high bandwidth modes This measurement is updated approximately once every 600 ms Examples LAS Idi response 30 0 means the measured laser output current is 30 0 mA Laser LDI response 100 0 means the measured laser output current is 100 0 mA 62 LDX 3232 Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer LDV REMOTE The LASer LDV command sets the laser voltage for calibration of the laser voltage white nrf space gt value gt measurement Syntax Diagram Parameters nrf value that represents the laser output voltage in volts Notes setpoint is the same for both low and high bandwidth output modes and is entered only for LDV calibration Examples Las LDV 4 action enters a value of 4 000 V LAS ldv 1 025 action enters a value of 1 025 V LASer LDV REMOTE The LASer LDV query returns the value of the measured laser voltage Syntax Diagram where the response is the measured laser output voltage for either low or high bandwidth modes Notes This measurement is updated approximately once every 600 ms Examples LAS ldv response 3 03 means the measured laser output voltage is 3 03 V Laser LDV response 1 0 means the measured laser output voltage is 1 000 V 01_10 LDX 3232 63 COMMAND REFERENCE LDX 3232 Device De
100. register via the ESE command and bit 5 of the Service Request Enable register via the SRE command Service request SRQ handling depends on your GPIB hardware Refer to your GPIB user s manual for details After a calibration value is entered the oPc query may be used to determine when the calibration sequence is done However the OPC wAI command or OPC query should not be issued until after the expected calibration value is entered or the system will hang This happens because the LDX 3232 Current Source will wait indefinitely for an input yet not allow any input until the calibration is finished Current Source Calibration There are three calibration adjustments required for the LDX 3232 Current Source They are calibration of the constant current source for both bandwidths and ranges calibration of the laser voltage measurement and calibration of the constant light power Ipp feedback circuits The LDX 3232 Current Source implements a two point calibration for the current source Two currents approximately 2096 and 8096 of FS are applied to a test load and the resulting actual currents are fed back by the user to the current source The laser current source calibration program uses the two sets of data to calculate new calibration constants These calibration constants are used to set the actual current of the current source The following procedure is for calibrating each range of the current source
101. rence LASer MDP FRONT PANEL REMOTE The LASer MDP command sets the value of the optical power setpoint in mW if the CALMD CAL PD responsivity is greater than 0 Syntax Diagram lt white space gt Parameters nrf value that represents the photodiode feedback power in mW Notes If the CALMD CAL PD parameter is set to 0 the LAS MDP value will not be used In this case the measured MDP would be invalid and the MDI lpp setpoint would be used Examples Las Mdp 40 action The LASER output is controlled so that the photodiode feedback power remains constant at 40 mW Laser MDP 200 action The LASER output is controlled so that the photodiode feedback power remains constant at 200 mW LASer MDP FRONT PANEL REMOTE The LASer MDP query returns the value of the laser photodetector power measurement in mW POE PO lt pe where the response is the most recent LASER power measurement Notes The response is in mW The response is valid even when the unit is not in constant P mode This measurement is updated approximately once every 600 ms Examples Las Mode MDP Las Calmd 460 Las MDp response 100 0 means 100 mW of photodetector power This feedback is controlling the laser current output LAS MODE IHBW LAS MDP response 20 0 means 20 mW of photodetector power but photodiode monitor current is not controlling the laser output current 70 LDX 3232 Lightwave COMMAND REFERENC
102. rent measurement is not displayed Las dis MDI response 1 means that the monitor photodiode current measurement is displayed LASer DISplay MDP FRONT PANEL REMOTE The LASer DISplay MDP command sets the display to show the monitor photodiode power measurement Syntax Diagram COP OPE Parameters None Notes The MDP measurement display is turned off automatically when another display selection is enabled Examples Las Display MDp action enables the display for photodiode power measurement values Laser Disp MDP action enables the display for photodiode power measurement values 01_10 LDX 3232 m 51 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer DISplay MDP REMOTE The LASer DISplay MDP query returns the status of the MDP monitor diode power measurement display mode Syntax Diagram Q where the response is 0 or 1 Notes In local operation the status of the MDP measurement mode is indicated by the enunciator next to the display mW will be illuminated and not blinking when the display is in MDP measurement mode Examples LAS DISp MDp response 0 means that the MDP measurement is not displayed Las dis MDP response 1 means that the MDP measurement is displayed LASer DISplay PARAM FRONT PANEL REMOTE The LASer DISplay PARAM command enables the display to show the parameter values Syntax Diagram Parameters Notes Examples
103. rth Alternating Visible and or refer to ground current invisible laser manual Terminal radiation A CNG x LDX Z3232 Lightwave 01 10 Caution risk Protective of electric Conductor A shock Terminal A Caution hot Frame or surface chassis Terminal On In position of a bistable push control or 1 d The slash I only denotes that mains are on Off Out position of a bistable push control The circle O only denotes that mains are off WARRANTY ILX LIGHTWAVE CORPORATION warrants this instrument to be free from defects in material and workmanship for a period of one year from date of shipment During the warranty period ILX will repair or replace the unit at our option without charge Limitations This warranty does not apply to fuses lamps defects caused by abuse modifications or to use of the product for that it was not intended This warranty is in lieu of all other warranties expressed or implied including any implied warranty of merchantability or fitness for any particular purpose ILX Lightwave Corporation shall not be liable for any incidental special or consequential damages If a problem occurs please contact ILX Lightwave Corporation with the instrument s serial number and thoroughly describe the nature of the problem Returning an Instrument If an instrument is to be shipped to ILX Lightwave for rep
104. s pa LAS GAL MEE puc kor CEN MES CALMD CAL DIS ENAB LIM MODE SET sese cw ESR RAD DEC CONST a SECURE 2 LDI COND 11 dHBW LDI IDN ae DIS LDI LDI 11 MDI OPC TERM DIS LDI LDV EVE 13 MDP MDP OPG i EVE LDV LDV EVE 13 d MDP PSC TIMER INC LDV MDI OUTOFF MDP PSC 101 MDI MDI OUTOFF ye PUD LDI MDI UM PUD LDV MDP RCL LDV SET ROT SET SAV MDI PARAM SRE MDLN SRE MDLN STB MDP TST MDP WAI MODE OUT OUT RAN RAN STEP STEP TOL TOL Figure 3 1 LDX 3232 Command Path Structure LDX 3232 M 25 01 10 REMOTE OPERATION IEEE488 2 Command Commands IEEE488 2 Command Commands The IEEE488 2 C x ommon Commands and Queries are distinguished by the that begins each mnemonic The diagrams below show the syntax structure for common commands common commands with numeric data required and command command queries Common Command 930 white Space Common Command with Numeric Data Common Command Query Decimal Numeric Program Data Numeric data is required with Psc 1 on O off RCL 0 to 10 see front panel RECALL function sav 1 to 10 see front panel SAVE function ESE 0 to 255 see Figure 3 2 SRE 0 to 255 see Figure 3 2 and PUD used at factory only
105. s 4000 LA the second setpoint will be about 1000 pA f Press and hold in the PARAMETER SET switch and turn the adjust knob until the display indicates the actual current as measured by the ammeter or as calculated LDX 3232 93 CALIBRATION AND TROUBLESHOOTING Local Calibration of the LDX 3232 Current Source g Release the PARAMETER SET switch to accept the second calibration point After the PARAMETER SET switch is released the LDX 3232 Series Current Source will calculate the calibration constants and store them to nonvolatile memory Laser Forward Voltage Measurement Calibration The following procedure is for calibrating the LASER voltage measurement Configure the Current Source in the following manner for the Laser Current Source Voltage calibration Function State LASER MODE constant current low bandwidth RANGE 2000 mA CURRENT LIMIT Set to FS full scale of range I SETPOINT 800 mA a With the current source output off connect a calibrated voltmeter in parallel with a resistor 15 O 5 W to the LASER output Laser Anode and Laser Cathode on the rear panel of the Current Source b Press the MODE ON switch to turn the current source output on The current source output must be on in order to enter the LDV calibration mode Enter the LASER V calibration mode by pushing the GPIB LOCAL and RANGE switches at the same time The display will blank and the Current So
106. s E514 on power up on display Hold GPIB LOCAL button RANGE button and FINE button as you are powering up the instrument This clears the laser board EEPROM LLLLL will be displayed on the display the laser current source must be recalibrated Instrument resets at power up or any LASER mode change Hold GPIB LOCAL button RANGE button and FINE button as you are powering up the instrument This clears the laser board EEPROM LLLLL will be displayed on the display the laser current source must be recalibrated LASER CURRENT SOURCE Power on but no current output Check interlock pins on LASER input connector on instrument rear panel these pins must be shorted either directly or though a switch IF OPEN CIRCUIT indicator is lit check the load connections and then try again Check the OUTPUT ON switch the corresponding LED should be lit Output current at limit can t be lowered If POWER mode is used check the monitor diode feedback connections try reversing the polarity of the monitor photodiode also check the photodiode bias adjustment on the rear panel If in l or lagw mode check the current setpoint and LIMIT setting setting the output below the limit may require several turns of the adjust know if the setpoint is much greater than the desired limit setting Output goes off intermittently Check the interlock circuit an intermittent interlock will turn the output off Check th
107. s the laser monitor photodiode feedback setpoint is 25 0 mW CALPD 0 LASer STEP NE REMOTE The LASer STEP command is used to increment or decrement the selected laser control mode setpoint by the given amount when used with the LASer INC or LASer DEC command lt white lt nrf space gt value gt Parameters integer value of the step amount the range 1 to 9999 Notes The step of one corresponds to the smallest display resolution for the mode For example a step of one means 0 1 mA 0 1 mW or 1 uA if CALPD 0 Examples Las Mode i Las ldi 20 Las Step 100 Las Inc Las set ldi action sets the step to 10 0 mA so the Las set ldi query will return a value of 21 0 mA LAS STEP 100 action sets the step size to 100 could mean 10 0 mA 10 0 mW or 100 pA 76 LDX 3232 Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer STEP REMOTE The LASer STEP query is used to read back the LASer STEP value This value is used to increment or decrement the selected laser control mode setpoint by the given amount when used with the LASer INC or LASer DEC command PON eoe where the response is an integer value Examples Las Mode LDI Las Step response 1 means the step size is 0 1 mA since Const mode is in effect LAS MODE MDP LAS CALMD 1 LAS STEP response 10 means the step size is 1 0 mW since Const P mode is in effect LASer TOLerance REMOTE
108. stable 0 15 V adjustable Temperature Coefficient 100 ppm C 100 ppm C Short Term Stability 1 hour 20 ppm 20 ppm Long Term Stability 24 hours 40 ppm 40 ppm Noise and Ripple uA rms High Bandwidth Mode 20 40 Low Bandwidth Mode lt 20 pA lt 20 pA Transients Operational lt 4 mA lt 4 mA 1 kV EFT Surge soma lt e mA Compliance Voltage Adjust Range 0 15V 0 15V Resolution 10 mV 20 mV Accuracy 20 40 Drive Current Limit Settings Range 1 to 2020 mA 1 to 4040 mA Resolution 10 mA 20 mA Accuracy 20 mA 40 mA Photodiode Feedback Type Differential Differential PD Reverse Bias 0 5V adjustable 0 5V adjustable PD Current Range 5 to 10 000 pA 5 to 10 000 pA Output Stability 0 02 0 02 Accuracy setpoint of FS 0 05 0 05 External Analog Modulation Input 0 10 V 1 ko 0 10 V 1 Transfer Function 200 mA V 400 mA V Lightwave 01 10 INTRODUCTION AND SPECIFICATIONS Specifications LDX 3232 Bandwidth 3 dB High Bandwidth DC to 250 kHz DC to 250 kHz Low Bandwidth DC to 10 kHz DC to 10 kHz Trigger Output TTL TTL Pulse Width 13 us 13 us Delay 12 ms 12 ms Measurement Display Output Current Range 0 to 2000 0 mA 0 to 4000 0 mA Output Current Resolution 0 1 mA 0 1 mA
109. t The OUTPUT switch has a toggling action Pressing the switch again will disable the current source output and the ON LED will not be illuminated The default condition for the current source output is off when the instrument is first powered up With the laser output enabled the LASER display should be indicating measured laser current If the output won t function check the following conditions 16 LDX 3232 Lightwave OPERATION Operating a Laser in Constant Power P Mode Conditions That Will Automatically Shut Off the LASER OUTPUT The following conditions will automatically cause the instrument to disable the current source output LASER High Power Limit LASER Interlock Key Lock Turned Off LASER Open Circuit or Voltage Limit Operating a Laser in Constant Power P Mode Suppose you want to operate a 3 mW laser at constant 1mW level The LDX 3232 allows you to operate the laser current source driver in a Constant Power mode In this mode the LDX 3232 drives current to the laser to reach a setpoint power value in mW The control loop feedback parameter is photodiode current that the LDX 3232 converts to optical power via a user defined photodiode responsivity number If laser power changes due to internal or environmental conditions the LDX 3232 will increase decrease the current to the laser to maintain the power setpoint The following paragraphs detail the instrument configuration in Constant Power Mode
110. t query Radix Hex Laser Event response H88 means that the LASER Power limit and Open circuit events have occurred since the last LASer EVEnt query 60 LDX 3232 Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer INC REMOTE The LASer INC command increments the selected laser control mode setpoint by one or more steps Optional parameters allow multiple steps to be incremented and the time in ms between increments to be set respectively This is an overlapped command Other commands may be executed while this function is in progress Syntax Diagram white nrf nrf space value p Aa Parameters 0 1 or 2 The first optional parameter is the number of steps and the second optional parameter is the number of ms between steps Notes The decremental default amount is one step The step size can be edited via the LAS STEP command LDX 3232 default values are 0 1 mA 0 1 mW or 1 pA If the first optional parameter is used but not the second the LASER setpoint is incremented by a multiple of the LAS STEP size without changing the LAS STEP size The second optional parameter is the time in ms between steps If both optional parameters are used the user may create an automated stepping ramp function for the LASER output If the first optional parameter is entered as zero LAS INC 0 the command will do nothing The minimum time to complete one increment is abo
111. t nrf value gt that represents the laser monitor photodiode power limit in mW When constant MDP mode is used the output level is limited only by the LIM Ix value Exceeding the powere limit will either cause the output to shut off default or generate a warning see LAS ENAB OUTOFF command LAS LIM MDP 10 action sets the laser output power limit to a value that corresponds to producing 10 00 mW of photodiode feedback optical power Las Limit MDp 5 action sets the laser output power limit to a value that corresponds to producing 5 00 mW of photodiode feedback optical power LASer LIMit MDP FRONT PANEL REMOTE The LASer LIMit MDP query returns the value of the laser monitor photodiode power limit Syntax Diagram POR PO G Notes Examples where the response is the LASER power limit setting The LASER MDP limit is in effect for both laser output current ranges The MDP limit is not in effect when CALMD O In this case the monitor current measurement is not converted to power LAS LIM MDP response 3 0 means the monitor photodiode power limit is set to 3 0 mW LAS Limit MDP response 10 0 means the monitor photodiode power limit is set to 10 0 mW Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer LIMit V FRONT PANEL REMOTE The LASer LIMit V command sets the LASER compliance voltage limit value white lt nrf space gt valu
112. t nrf value gt whose sum represents the enabled bits LASER Current Limit 256 N A LASER Voltage Limit 512 Output is out of tolerance N A 1024 N A Power limit with output on 2048 N A N A 4096 N A N A 8192 N A N A 16384 N A N A 32768 N A The enabled LASER outoff bits can be read by using the LASer ENABle OUTOFF query The enable registers normally retain their values at power up as they were at power down unless the power on status clear flag is set true for more information see the PSC definition in the GPIB IEEE488 specification The factory default value for this register is B0000100000001000 H808 or 2056 decimal LAS ENAB OUTOFF 9 action enables the LASER status outoff register so that Power limit and LASER current limit conditions will cause the LASER output to be turned off Las Enab Outoff HEOB action enables the LASER status outoff register so that any or all of the above conditions will cause the LASER output to be turned off Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer ENAB1le OUTOFF FRONT PANEL REMOTE The LASer ENABle OUTOFF query returns the value of the status outoff enable register of the LASER operations Syntax Diagram PON 0 0 0 where the response is the sum of the following 1 LASER Current Limit 256 N A 2 LASER Voltage Limit 512 Output if out of tolerance 4 N A 1024 N A 8 Power limit with output on 2048 N A 16 N A 4096 N A
113. tage measurement This procedure is outlined in Chapter 6 The LASer CAL LDV query may be used to determine if the LDX 3232 is ready for the user to enter a value Las CAL Ldv action the LDX 3232 enters calibration mode for LASER voltage Las Cal LDV action the LDX 3232 enters calibration mode for LASER voltage Lightwave 01 10 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer CAL LDV FRONT PANEL REMOTE The LASer CAL LDV query is used to determine that the LDX 3232 is ready for a value to be entered during the calibration cycle of the LASer CAL LDV mode Syntax Diagram Pop HOR POLO Notes After this query is issued and a response of 1 is received the LDX 3232 will be ready for the user to enter a voltage value via the LASer LDV command see Chapter 6 Examples LASer CAL LDV response 1 means the LDX 3232 is ready for the user to enter a voltage value via the LASer LDV command LASer Cal LdV response 0 means the LDX 3232 is not yet ready for the user to enter a LASER voltage value LASer CAL MDI FRONT PANEL REMOTE The LASer CAL MDI command is used to enter the LASER photodiode current calibration mode Syntax Diagram 6 6 Parameters None Notes After this command is issued the LDX 3232 will automatically enter the LASER photodiode current calibration mode When the LDX 3232 is ready the user should enter the true measured value This procedure
114. the AC power source matches the setting of the LDX 3232 s voltage printed on the rear panel of the instrument To avoid electrical shock hazard connect the instrument to properly earth grounded 3 prong receptacles only Failure to observe this precaution can result in severe injury or death Lightwave INTRODUCTION AND SPECIFICATIONS Installing Your LDX 3232 High Compliance Current Source GPIB Connector The IEEE 488 GPIB interface connector is located on the rear panel directly above the power input module and fuse See Figure 1 2 LDX 3232 Rear View Attach the GPIB cable to the 24 pin connector located on the rear panel The connector is tapered to ensure proper orientation Using your fingers tighten the two screws on the cable connector A total of 15 devices can be connected together on the same GPIB interface bus The cables have single male female connectors on each end so that several cables can be stacked This allows more than one cable to be attached to any one device However the maximum length of the GPIB cables must not exceed 20 meters 65 feet total or 2 meters 6 5 feet per device The GPIB Address The talk and listen addresses on the LDX 3232 High Compliance Current Source are identical This GPIB address is read locally by pressing the GPIB LOCAL switch with the address displayed on the LED display The instrument comes from the factory configured with the GPIB address set to 1 You can change t
115. the original setup for the first experiment any time using the RECALL function To enter the SAVE RECALL mode press the SELECT switch in the PARAMETER section until the SAVE indicator LED becomes lit and the unit displays the SAVE bin on the display If another bin number is desired press and hold the SET switch and rotate the adjust knob until the desired bin number is displayed Releasing the SET switch completes the SAVE operation and all of the instrument parameters are saved to the indicated bin number as they appear on the front panel LDX 3232 83 FUNCTIONS AND FEATURES Saving and Recalling Under Remote Operation To recall a previously saved instrument setup press the SELECT switch until the RECALL indicator led becomes lit The instrument will display a RECALL bin number on the display If you desire to change the RECALL bin press and hold the SET switch and rotate the adjust knob until the desired bin number is displayed Releasing the SET switch completes the RECALL operation The instrument is restarted and the front panel parameters are reconfigured to the new parameters saved under that bin number The factory default values for front panel parameters may be restored by recalling bin zero 0 See Table 2 1 for the default settings Saving and Recalling Under Remote Operation For saving under remote operation use the command SAV x where x is the desired bin number 1 10 For a recall under remote op
116. the outputs of the Laser Current Source Press the MODE ON switch to turn the current source output on The output must be on in order to enter the LASER calibration mode d Enter the LASER I calibration mode by pushing the GPIB LOCAL and DISPLAY SELECT switches at the same time The display will blank and the Current Source will drive the current output to the setpoint and the Display will indicate output current in mA e Calculate the actual current through the load as described in step b Press and hold in the PARAMETER SET switch and turn the adjust knob until the display indicates the calculated actual current f Release the PARAMETER SET switch After the PARAMETER SET switch is released the Current Source will drive the current output to about 2596 of the first calibration setpoint Calculate the measured current again through the load resistor h Press and hold in the PARAMETER SET switch and turn the adjust knob until the display indicates the actual current as calculated in step g i Release the PARAMETER SET switch to accept the second calibration point After the PARAMETER SET switch is released the Current Source will calculate the calibration constants and store them to nonvolatile memory In low bandwidth calibration mode the LDX 3232 Series Current Source will also perform current limit calibration indicated by the CURRENT LIMIT LED flashing j Turn the current source output off Change th
117. tored in non volatile memory 78 LDX 3232 Lightwave 01 10 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference MESsage Notes Examples RADix Parameters Notes Examples REMOTE The MESsage query returns the previously stored message This message will always be 16 bytes long and enclosed in quotes The message is entered via the MESsage command where the response is a 16 byte long character string The response data will be a 16 byte long string If there is no previously stored message the response will be all spaces MES response Test 3 means the previously stored message was Test 3 Message response This is a test means the previously stored message was This is a test REMOTE The RADix command allows the programmer to select the radix type for status condition and event query response data Decimal binary hexadecimal and octal are allowed lt white space gt As shown above character program data is expected DECimal is the default type Only the first three letters of the words decimal hexadecimal binary or octal are required When the RADIX is selected all status condition and event queries will return values in the new radix In the cases where the radix is not DECimal the flexible numeric type lt nrf value gt as shown in the Command Reference diagrams will be replaced by HEX BIN or OCT representation
118. uh User s Guide Pet High Compliance Current Source LDX 3232 HIGH COMPLIANCE LASER DIODE CURRENT SOURCE mS Lightwave ox 3232 PD INTERLOCK VOLTAGE UMIT CURRENT UMIT OPEN CIRCUIT POWER UMIT IN LX Lc ves A Newport Corporation Brand ILX Lightwave Corporation 31950 Frontage Road Bozeman MT U S A 59715 U S amp Canada 1 800 459 9459 International Inquiries 406 556 2481 Fax 406 586 9405 ilx custhelp com www ilxlightwave com 70037802 January 2010 TABLE OF CONTENTS E H H H H a El El H H El E a H Ei Safety Information and the ix General Safety Considerations ix Safety Marking Symbols X Comments Suggestions and Problems xiii Chapter 1 Introduction and Specifications Product Overview 1 Initial Inspection elve teas 2 Installing Your LDX 3232 High Compliance Current Source 2 Grounding Requirements 2 AC Line Power Requirements 2 GPIB Connector 3 The GPIB Address 3 Tilt Foot Adjustment III el ll nen eae 3 Operating the LDX 3232 Precision Current Source 3 Mai
119. urce will drive the LASER current output to the respective setpoint and the display will indicate forward voltage in Volts d Enter the measured voltage in volts Press and hold in the PARAMETER SET switch and turn the adjust knob until the display indicates the measured voltage e Once the actual voltage value is entered the Current Source will set the current to approximately one fourth 1 4 of the original value It will then expect the second calibration voltage point f Input the second actual measured LASER forward voltage as in Step d g Once the second actual voltage value is entered the Current Source will store the new calibration constants This ends the section on front panel calibration of your LDX 3232 Current Source The next section discusses calibration through the GPIB IEEE488 interface 94 LDX 3232 Lightwave CALIBRATION AND TROUBLESHOOTING Remote Calibration of the LDX 3232 Current Source Remote Calibration of the LDX 3232 Current Source The LDX 3232 Current Sources can be calibrated remotely via the GPIB Interface All of the required calibration commands are listed in Table 4 1 in Chapter 4 The procedures below are general guidelines for writing a program to calibrate your instrument Note The operation complete flag bit 0 of the Standard Event Status Register may be used to trigger a service request This type of interrupt is enabled by setting bit O of the Service Request Enable
120. ure 2 5 Back Panel LD Connector 12 Figure 3 1 LDX 3232 Command Path Structure 25 Figure 3 2 LDX 3232 Status Reporting Schematic Diagram 29 Figure 3 3 LDX 3232 Output Off Register 31 Figure 4 1 Command Description Format 39 Figure 5 1 LDX 3232 Rear 85 Figure 6 1 lpp Calibration Circuit 91 01_10 LDX 3232 BN SEE Lightwave LIST OF TABLES E H H H H B El El a a El a a El Table 2 1 LDX 3232 Default Settings 10 Table 2 2 LDX 3232 Error Indicators 19 Table 3 1 Substitute Parameter 23 Table 3 2 LDX 3232 Often Used Commands 27 Table 3 3 LDX 3232 Series Default Settings for Output Off Registers 30 Table 3 4 Error Code 5 lt 33 Table 3 5 LDX 3232 Series Error 33 Table 4 1 LDX 3232 Series Device Dependent Commands 35 Table 6 1 Recommended Test Equipment 90 Table 6 2 Required Calibration ComponentS 90 Table 6 3 Error Code 5 lt 101 Table 6 4 LDX 3232 Series Error Codes 101 01 10 LDX 3232 vii En viii LDX 3232 Lightwave SAFETY
121. ut 20 ms Therefore values for the second optional parameter time between increments have a practical minimum of 20 This command should not be overlapped with LAS DEC or other LAS INC commands Examples LAS MODE I LAS STEP 3 LAS INC action The laser source current setpoint is incremented by 0 03 mA LAS MODE I LAS STEP 3 LAS INC 3 action The laser source current setpoint is incremented by three times the amount described in the first example LAS MODE I LAS STEP 3 LAS INC 3 5000 action The laser source current setpoint is incremented by the amount described in the first example three times with fiveseconds between incremental steps LAS STEP 1 LAS Mode P Las INC action The power setpoint is incremented by 0 01 mW 01_10 LDX 3232 m 61 COMMAND REFERENCE LDX 3232 Device Dependent Command Reference LASer LDI FRONT PANEL REMOTE The LASer LDI command sets the laser control current Syntax Diagram lt white space gt Parameters nrf value that represents the laser output current in mA Notes setpoint is the same for both low and high bandwidth output modes Examples Las LDI 400 action sets the laser output current to 400 00 mA LAS Idi 100 action sets the laser output current to 100 0 mA LASer LDI FRONT PANEL REMOTE The LASer LDI query returns the value of the measured laser current Syntax Diagram PON Ha X po where the response is the most
122. will be continuously displayed Examples LAS DISPLAY SET response 0 means the setpoint is not shown on the display Las Dis Set response 1 means the setpoint value is shown on the display LASer ENABle COND The LASer ENABle COND command sets the condition status enable register of the LASER operations for summary in bit 3 of the status byte and generation of service requests Syntax Diagram lt white nrf space value Parameters nrf value whose sum represents the enabled bits 1 LASER Current Limit 256 Output is shorted 2 LASER Voltage Limit 512 Output is outside tolerance limit 4 N A 1024 Output on off state 8 Power limit 2048 Ready for calibration data state 16 Interlock disabled 4096 N A 32 N A 8192 N A 64 Compliance Voltage Limit 16384 128 Open circuit 32768 Notes The enabled or disabled LASER conditions can be read by using the LASer ENABle COND query The LASER condition status can be monitored by the LASer COND query If any of the enabled LASER conditions are true bit 3 of the status byte register will be set The enable registers normally retain their values at power up as they were at power down unless the power on status clear flag is set true for more information see the PSC definition in the GPIB IEEE488 specification 54 LDX 3232 Lightwave COMMAND REFERENCE LDX 3232 Device Dependent Command Reference Examples LAS ENAB COND 12
123. y press the LOCAL switch in the section labeled GPIB on the front panel The instrument will display the address The default address from the factory is address Adr 01 Changing the GPIB Address Every device on the GPIB bus must have a unique address If it is necessary to change the address press and hold in the PARAMETER SET switch while displaying the GPIB address Turn the ADJUST knob until the desired address value is displayed then release the SET switch The new GPIB address will then be stored in non volatile memory The allowable address range is 0 30 for primary GPIB addressing Extended GPIB addressing is not implemented on the LDX 3232 at this time LDX 3232 21 22 REMOTE OPERATION LDX 3232 Current Source Command Set Changing Operation from Local to Remote Sending a command over the GPIB will automatically put the instrument in REMOTE mode The REMOTE indicator will REMOTE identify when the Current Source is in remote operation mode X When the instrument is in REMOTE mode pressing the LOCAL switch returns the instrument to LOCAL control mode unless a 1 Local Lockout state has been activated by the low level GPIB LOCAL command LLO from the host computer Local Lockout disables all LDX 3232 High Compliance Current Source front panel switches until this condition is changed by the host computer In this condition the REMOTE indicator will flash at a 1Hz rate The TALK LISTEN indicator is illum
124. y will supply you with a quotation for estimated costs of repair You must negotiate and settle with the carrier for the amount of damage xii LDX 3232 Lightwave 01 10 Comments Suggestions and Problems To ensure that you get the most out of your ILX Lightwave product we ask that you direct any product operation or service related questions or comments to ILX Lightwave Customer Support You may contact us in whatever way is most convenient Phone exer wee es 800 459 9459 406 556 2481 pleats Saddle ee a aka 406 586 9405 Online FAQ 2 www ilxlightwave com Or mail to ILX Lightwave Corporation Box 6310 Bozeman Montana U S A 59771 www ilxlightwave com When you contact us please have the following information Model Number Serial Number End User Name Company Phone Fax Description of what is connected to the ILX Lightwave instrument Description of the problem If ILX Lightwave determines that a return to the factory is necessary you are issued a Return Authorization RA number Please mark this number on the outside of the shipping box You or your shipping service are responsible for any shipping damage when returning the instrument to ILX Lightwave ILX recommends you insure the shipment If the original shipping container is not available place your instrument LDX 3232 xiii

LDX-3232 Device-Dependent Commands

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