Home

LDC-3700C Series Laser Diode Controllers

1. Name Parameters Function TEC CAL ITE NONE Returns the ready state for entering a TE current source calibration value TEC CAL SEN 1 Used to enter the sensor calibration mode TEC CAL SEN NONE Returns the ready state for entering a sensor calibration value TEC CAL V 1 Used to enter the TEC voltage calibration mode TEC CAL V NONE Returns the ready state for entering a TEC voltage calibration value TEC CONST 1 3 Used to enter temperature sensor constants C1 C2 and C3 TEC CONST NONE Used to read back the temperature sensor constant values TEC DIS 1 Turns the TEC display on or off TEC DIS NONE Returns the TEC display value on off TEC DIS ITE NONE Turn on off TEC display to show TEC current TEC DIS ITE NONE Returns status of TE current display on off TEC DIS R NONE di on off display to show the temperature sensor value V 1 or TEC DIS R NONE Returns status of sensor value display on off TEC DIS SET NONE Shows the TEC display set point corresponding to TEC mode TEC DIS SET NONE Returns status of TEC set point display on off TEC DIS T NONE Turns on off TEC display to show temperature TEC DIS T NONE Returns status of temperature display on off TEC ENAB COND 1 Sets the enable register for TEC conditions TEC ENAB COND NONE Returns the value of the TEC conditions enable register TEC ENAB EVE 1 Sets the enable register for TEC events TEC ENAB EVE NO
2. E 210 PROGRAM DATA gt will not convert to a floating point value E 211 PROGRAM DATA gt will not convert to a character value E 213 PROGRAM is incorrect block data length E 214 PROGRAM length exceeds maximum E 301 A RESPONSE MESSAGE was ready but controller failed to read it Query error E 302 Query error Device was addressed to talk but controller failed to read all of the RESPONSE MESSAGE E 401 TEC Temp Limit booster interlock disabled output E 402 Sensor open disabled output E 403 TEC module open disabled output E 404 TEC Current limit disabled output E 405 TEC Voltage limit disabled output E 407 TEC high temperature limit disabled output E 408 Booster change disabled TEC output E 409 Sensor change disabled TEC output E 410 TEC out of tolerance disabled output E 411 TEC control error disabled output E 412 Analog section status is all 1 s or all O s power down E 413 Serial EEPROM checksum error E 415 Sensor short disabled TEC output E 416 Incorrect Configuration for Calibration Sequence to start E 419 Setting a measurement is only valid during the calibration phase for that measurement User has tried to calibrate a measurement without first entering the required calibration mode E 501 LASER interlock disabled output E 503 LASER open circuit disabled output E 504
3. LINE VOLTAGE FUSH RATI EX o 0000 00000 0005 Figure 2 4 LDC 3700C Series Rear Panel Modulating the Controller Laser Current Source The LDC 3700C Series Laser Diode Controller allows a modulated signal to be superimposed on the LASER injection current For example assume you are using an LED for your experiment where you need operate the led in constant current at Pop 1 mW and a modulated injection current from 3 to 30 kHz The experiment requires the LDC 3724C s laser controller to be configured for the 200 mA range high bandwidth mode with a limit of 175 mA The allowable bandwidth of the modulated signal defined as the 3 dB roll off point is dependent on the LDC 3700C Series family member the LASER current range and the LASER mode constant current low high bandwidth See the section LASER CURRENT SOURCE SPECIFICATIONS in Chapter 1 for external analog modulation bandwidth specifications Setting up the controller for a modulated laser injection current is easy The MOD EXTERNAL connector on the front panel is the input for the modulated signal The modulation port input impedance is 1 The transfer function mA V shown is for the LDC 3724C This transfer function varies by model and laser drive current output range The transfer function for the low and high current ranges of the LDC 3714C are 5 mA V an
4. 153 Laser Forward Voltage Measurement Calibration 154 Troubleshooting 155 Error Messages 157 iv 7 LDC 3700C Series Lightwave 04_09 Figure 1 1 Figure 1 2 Figure 2 1 Figure 2 2 Figure 2 3 Figure 2 4 Figure 2 5 Figure 3 1 Figure 3 2 Figure 3 3 Figure 3 4 Figure 3 5 Figure 3 6 Figure 3 7 Figure 5 1 LIST OF FIGURES B El Bl L E E El a a LDC 3700C Series Controller Front View 4 LDC 3700C Rear Panel 4 Laser Diode Connection Configurations 16 Back Panel LD Connector 17 Rear Panel TEC 19 LDC 3700C Series Rear Panel 39 Rear Panel TEC 41 GPIB Cable Connections 45 GPIB Connector Diagram 46 Command Path Structure 51 Common Command Diagrams 53 Status Reporting Scheme 57 LASER Output Off Register 59 TEC Output Off 5 59 lpp Calibration Circuit 137 LDC 3700C Series v vi 7 LDC 3700C Series Lightwave LIST OF TABLES E L L L L B El El Bl a El E El Table 1
5. Okay Not Okay DIS DS Disp dsp Displ dply Displa DSPLY Display disply White Space White space is normally the space character space bar A single white space must separate a command from its parameters or data For example Okay Not Okay DELAY 500 DELAY500 To enhance readability you can also use one or more white spaces before a comma semicolon or terminator Since your computer normally puts the terminator at the end of each command string line this simply means that an extra space character at the end of your command line works OK A query has no space between the mnemonic and the question mark For example Okay Not Okay TIMER TIMER Note that too many consecutive white spaces can overflow the 256 byte data I O buffer 48 LDC 3700C Series Lightwave 04_09 REMOTE OPERATION Command Syntax Terminators A program message terminator identifies the end of a command string For GPIB these are the valid terminator sequences NL END lt NL gt lt END gt Many computers terminate with lt CR gt lt NL gt lt END gt Carriage Return New Line EOI A carriage return CR is read as white space For USB the only valid terminator is NL The LDC 3700C terminates its responses with lt CR gt lt NL gt lt ENDs gt unless you use the TERM command to change it If you encounter problems wit
6. lt 45 The GPIB Connector 45 Reading the GPIB Address 46 Changing the GPIB Address 46 Changing Operation from Local to Remote 47 Command Syntax 48 Letters IR wag Xa NOM 48 White Space cce exse Ee ERE ed eee ee 48 Termlnators rer TAG ERU RS PARS 49 Command Separators 49 Parameters 49 Command Tree Structure 50 Syntax Summary 51 IEEE488 2 Common Commands 53 LDC 3700C Commonly Used Commands 54 Status Reporting 55 Event and Condition Registers 55 Operation Complete 56 Output Off Registers 58 Command Timing 61 Sequential Overlapped Commands 61 Query Response Timing 61 04 09 LDC 3700C Series iii L n dM
7. 2 Grounding 1 2 AC Line Power Requirements 2 Dij 2 GPIB Connel cerci c Ga as etae e Sd ee a a Ra o n 3 The GPIB Address x uet tee eec ee Go de a 3 Tilt Foot 3 Rack 0 4 4 404 4 3 Operating the LDC 3700C Laser Diode 3 How to Obtain Repair Services 5 Laser Current Source 6 Temperature Controller Specifications PLE 8 General LDC 3700C Specifications 9 Available Options and Accessories 11 04 09 LDC 3700C Series L Chapter 2 Operations Applying Power to your LD 13 The Power On Sequence 13 The Power On State 14 37x4C Series Default Configuration 14 Connecting to the Laser Controller 15 Connecting the Laser Current Source 17 Interlock Connections 17 Photodiode Connections
8. nrf value whose sum represents the enabled bits 1 TE Current Limit 256 N A 2 Voltage Limit Error 512 Output Changed to be In Out of Tolerance 4 N A 1024 Output On Off Changed 8 High Temperature Limit 2048 New Measurements Taken 16 TEC Interlock Disabled 4096 N A 32 Booster Enable 8192 N A 64 Sensor Open 16384 N A 128 TE Module Open 32768 N A Notes The enabled TEC events can be read by using the TEC ENABle EVEnt query The enabled TEC event status can be monitored by the TEC 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 see PSC Chapter 3 Examples Tec Enab EVENT 160 action enables the TEC status event register so that the TE Module Open and Booster Changed conditions will be reported in summarized form to the status byte register bit 1 Tec Enable EVEnt HOEFB action enables the TEC status event register so that any and all of the above events will be reported in summarized form to the status byte register bit 1 118 LDC 3700C Series Lightwave COMMAND REFERENCE Command Reference TEC ENABle EVEnt COMMON DEVICE DEPENDENT FRONT PANEL The TEC ENABle EVEnt query returns the value of the status event enable register of the TEC operations 1 TE Current Limit 256 N A 2 Voltage Limit Error 512 Output Changed to be In Out of Tolerance 4 N A 1
9. No operations to the LASER current source hardware are pending No operations to the TEC hardware are pending No EEPROM non volatile memory write cycles are in progress 56 LDC 3700C Series Lightwave REMOTE OPERATION Command Syntax arent Limit LASER Conditior e Register Limit User foe TEBE BETTS 3 Power Limit n A Interlock Error LOGICAL OR vic Operation Complet trr rrr do Request Control 1 2 Query Error Dependent Error LASER Event Status Register O LASER Current Limit B Tod LASer EVEn Vollag Limit er Limit lock Error N A le 6 l LOGICAL OF 8 9
10. 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 LDC 3700C Series Laser Diode Controller will wait indefinitely for an input yet not allow any input until the calibration is finished Thermistor Calibration The following procedure is for calibrating the 100 A and 10 uA thermistor current sources so that the thermistor resistance measurement for these ranges will meet the stated accuracy specifications 1 Set the SENSOR SELECT switch back panel to the 100 pA position the TEC display code is 01 2 Using the multimeter measure and record the exact resistance of your metal film resistors A 4 point probe resistance measurement is recommended 3 Connect the correct metal film resistor See Table 5 1 on page 136 to the sensor input of the Temperature Controller 15 pin connector on the rear panel Sensor and Sensor terminals 4 Enterthe TEC CAL SENsor command over the GPIB The TEC display will show the resistance value and will then expect the actual value to be entered in If this calibration value is to be measured and entered remotely via a GPIB controlled DMM for example the actual value of the resistance should not be entered until the Controller is ready to receive it The Controller will be ready to receive the actual measured resistance value when after a TEC CAL SEN query is sent the resp
11. ADJUST 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 LDC 3700C Controller uses the responsivity value entered to calculate a power limit This is a software limit only To set the Constant Power limit use the SELECT push button in the PARAMETER LASER section to select LIM P When the LIM P is indicated by the accompanying LED the LASER display will indicate the limit set point in mW Press and hold the SET push button and rotate the adjust knob clockwise to increase the limit set point value or counterclockwise to decrease the limit set point value Set the limit to 1 50 mW When the desired value is reached release the SET push button to store the new limit value EE PARAMETER mmm LASER C3 LIMITE LJ UMI C3 LIM THI UMI C3 CONST SHET UMP C3 GAIN CAL PD C3 I SAVE RECALL The LIM P is the absolute limit of optical power as detected by the unit via the monitor PD 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 i
12. all spaces Examples 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 1027 LDC 3700C Series Lightwave COMMAND REFERENCE Command Reference OPC Operation Complete DEVICE DEPENDENT FRONT PANEL Action Sets the operation complete bit in the Event Status Register when all pending overlapped commands have been completed Response None Example OPC OPC COMMON Operation Complete Query Action Places an ASCII character 1 into the intrument s Output Queue when all pending operations have been finished Response 1 when all overlapped commands are complete Example OPC PSC nrf value COMMON Power on Status Clear Action Sets automatic power on clearing of the enable registers Values 0 disable power on clearing 1 enable power on clearing Notes Any non zero value is interpreted as 1 Registers affected Condition Status Enable Service Request Enable Event Status Enable Standard Event Status Enable Factory default condition disabled In the disabled state the values of the enable registers are saved through power OFF ON The power on status clear flag see PSC is set false disallowing service request interrupts after power on In the enabled state the enable registers are cleared during power ON The power on status clear flag see PSC is set true al
13. CONNECTORS Photodiode Monitor and Current Source Connector 9 pin D sub female External Modulation Connector BNC Temperature Controller 15 pin D sub female Trigger Output BNC Chassis Ground 4 mm banana jack GPIB INTERFACE Meets ANSI IEEE Std 488 1 1987 Meets ANSI IEEE Std 488 2 1987 USB INTERFACE LDC 3700C Series 9 10 INTRODUCTION AND SPECIFICATIONS General LDC 3700C Specifications GENERAL Size H x W x D 5 0 x 13 9 x 13 6 127 mm x 353 mm x 345 mm Weight LDC 3714C 722 5 Ibs 10 2 kg LDC 3724C 722 5 lbs 10 2 kg LDC 3744C 25 Ibs 11 3 kg Power Requirements 100 115 VAC 220 240 VAC 48 66 Hz Temperature 0 C to 40 C operating 40 C to 70 storage Humidity 90 relative humidity non condensing Laser Safety Features Key switch interlock and output delay meets CDRH US21 1040 10 LASER Display Type 5 digit green LED TEC Display Type 5 digit green LED LDC 3700C Series Lightwave INTRODUCTION AND SPECIFICATIONS General LDC 3700C Specifications Available Options and Accessories Options and accessories available for the LDC 3700C Series Controllers include the following Table 1 1 Options and Accessories DESCRIPTION MODEL NUMBER Rack mount flange kit RM 136 enables installation into a standard 19 i
14. 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 which 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 repair 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 LDC 3700C Series xi TJ 3 Attach the anti static protective caps that were shipped with the instrument and place the instrument in protective anti static bag 4 Place the instrument in the original packing container with at least inches 7 5 cm of compressible packag
15. ps o 0000 00000 0005 Figure 1 2 LDC 3700C Rear Panel WARNING Potentially lethal voltages exist within the LDC 3700C Series Laser Diode Controller To avoid electric shock do not perform any maintenance on the instrument Qualified service personnel are required to wear protective eyeglasses and anti static wrist bands while working on the LDC 3700C Series Laser Diode Controller circuit boards High voltages are present on and around the controller s printed circuit boards There are no user serviceable parts in the instrument including the external fuses in the AC power entry module Contact ILX Customer Service for information about servicing the instrument 8 LDC 3700C Series Lightwave INTRODUCTION AND SPECIFICATIONS Installing the LDC 3700C How to Obtain Repair Services You may have to return your controller to the ILX Lightwave facility at some time for repair or service whether it is under warranty or not There is a charge for repairs after the warranty period has expired See Returning an Instrument on page xi for shipping information and Customer Service contact information 04 09 LDC 3700C Series 5 Bd E 1 INTRODUCTION AND SPECIFICATIONS Laser Current Source Specifications Laser Current Source Specifications LDC 3714C LDC 3724C LDC 3744C DRIVE CURRENT OUTOUT Output Current
16. 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 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 N A 16384 N A 128 Open Circuit 32768 N A 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 LDC 3700C Series current limit events have occurred since the last LASer EVEnt 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 Lightwave 04_09 COMMAND REFERENCE Command Reference 1 LASer INC nrf value gt lt nrf value Parameters Notes Examples DEVICE DEPENDENT The LASer INC command increments the selected laser control mode set point by one or more steps Optional parameters allow multiple steps to be incremented and the time in milliseconds between increments to be set respectively 0 1 or 2 The first optional parameter is the number of steps and the second optional parameter is the number of
17. Chapter 4 Command Reference Remote Command Reference 64 Command Reference 69 Chapter 5 Calibration and Troubleshooting Calibration Overview 135 Recommended Equipment 136 Local Calibration of the LDC 3700C Temperature Controller 139 Calibrating the Thermistor 139 AD590 Sensor Calibration 140 LM335 Sensor Calibration 140 ITE Current Calibration 141 Local Calibration of the Laser Current 142 Current Source Calibration 142 lpp Current Calibration 144 Laser Forward Voltage Measurement Calibration 146 Remote Calibration of the LDC 3700C Controller 147 Thermistor Calibration 147 AD590 Sensor Calibration 148 LM335 Sensor Calibration 148 Current Calibration 149 TEC Voltage Calibration 150 Current Source Calibration 151 lpp Current Calibration
18. DELAY 1 Used to create a delay in the execution of further commands ERR NONE Returns errors generated since the last query ESE Used to load the Standard Event Status Enable Register ESE Sets the summary bit bit 5 in the Status Byte ESR Returns the value of the STANDARD EVENT REGISTER IDN Returns the DEVICE IDENTIFICATION string LAS 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 enter the laser voltage calibration mode LAS CAL LDV NONE Returns the ready state for entering the laser voltage calibration value LAS CAL MDI NONE Used to enter the monitor photodiode current calibration mode LAS CAL MDI NONE Returns the ready state for entering the monitor PD current calibration value LAS COND NONE Returns the value of the LASER condition register LAS DEC 0 10r2 Used to decrease the laser current set point value by one or more steps 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
19. DEVICE DEPENDENT FRONT PANEL The TEC MODE R command selects TEC constant thermistor resistance linear sensor reference mode None Since sensor resistance or linear sensor reference is a function of temperature this mode also controls the TEC output load temperature but it bypasses the use of the conversion constants for set point calculation This allows finer control of temperature in cases where the sensor s temperature model and therefore the constants is not known Changing modes causes the output to be forced off and the new mode s set point value will be displayed TEC MODE R action sets the TEC controller for constant thermistor resistance linear sensor reference operating mode Tec Mode R action sets the TEC controller for constant thermistor resistance linear sensor reference operating mode TEC MODE T Parameters Notes Examples DEVICE DEPENDENT FRONT PANEL The TEC MODE T command selects TEC constant temperature control mode None Since TEC load temperature is derived from sensor resistance reference constant R and T modes are related In T mode the set point is converted to resistance or reference using the appropriate constants and conversion model Changing modes causes the output to be forced off and the new mode s set point value will be displayed TEC MODE T action sets the TEC controller for constant load temperature operating mode tec mode T action sets the TEC controller for con
20. TEC DISPLAY enabled in T mode TEC Display showing actual temperature Constant T mode selected Temperature Set Point 20 C LIM Tu set to 99 9 C Ite Set Point 1 0 Amp LIM ITE 2 0 Amps GAIN 30 C1 1 125 x 10 C2 2 347 x 104 0 855 x 107 TEC Tolerance values 0 2 C 5 seconds TEC output off LASER Tolerance values 1 0 mA 1 0 s 3724C 3714C Resistance Reference Set Point 1 ohm mA mV depending on the setting of the SENSOR SELECT switch Lightwave OPERATIONS Connecting to the Laser Controller Connecting to the Laser Controller When connecting your laser diode or any other sensitive devices to the LDC 3700C Series Laser Diode Controller ILX recommends that the instrument be powered up and the LASER output be off LASER MODE ON LED unlit In this condition a low impedance shunt is active across the output terminals When disconnecting devices it is only necessary to turn the LASER Output off ILX also recommends that the connections to the LDC 3700C Series Laser Diode Controller output be made using twisted wire pairs with an earth grounded shield see Figure 2 1 on page 16 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 a
21. The decremental default amount is one step The step size can be edited via the LAS STEP command LDC 3714C default values are 0 001 0 002 mA 50 100 mA range 0 01 mW or 1 uA if CALMD 0 depending on the mode of operation LDC 3724C default values are 0 01 mA 0 01 mW or 1 pA LDC 3744C default values 0 1 mA 0 1 mW or 1 PA If the first optional parameter is used but not the second the user may decrement the LASER set point by a multiple of the LAS STEP size without changing the LAS STEP size If the 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 DEC 0 the command will do nothing The minimum time to complete one decrement is about 20 msec Therefore values for the second optional parameter time between decrements have a practical minimum of 20 LAS MODE I LAS STEP 3 LAS DEC action The laser source current set point is decremented by 0 3 mA LDC 3744C or 0 03 mA LDC 3724C or 0 003 mA LDC 3714C on 50 mA range or 0 006 mA LDC 3714C on 100 mA range LAS MODE I LAS STEP 3 LAS DEC 3 action The laser source current set point is decremented by three times the amount described in the first example LAS MODE I LAS STEP 3 LAS DEC 3 5000 action The laser source current set point is decremented by the amount described in the first example three times with 5 seconds between decrement
22. 04 09 DEVICE DEPENDENT FRONT PANEL The TEC T query returns the value of the TEC temperature measurement The measured TEC temperature is valid for all modes of TEC operation Temperature is continually updated This measurement is updated approximately once every 600 msec The response value has 6 digits of precision TEC T response 10 4231 means the measured TEC load temperature is 10 4231 C Tec Mode R Tec T response 3 0778 means the measured TEC load temperature is 3 07780 C LDC 3700C Series 129 130 COMMAND REFERENCE Command Reference TEC TOLerance Parameters Notes Examples LDC 3700C Series DEVICE DEPENDENT The TEC TOLerance command allows the programmer to determine the TEC temperature tolerance and time window for it to occur in order that the operation complete flag be set after a TEC OUTput 1 command is issued or the set point is changed One or two nrf values the first represents the temperature tolerance in with a range of 0 1 C to 10 0 C and the second represents the time window in seconds with a range of 0 001 to 50 0 seconds This command may be used in conjunction with the TEC COND to test for and delay further program activities until the TEC temperature reaches its set point to the specifications of the TEC TOLerance command For example if the set point is 10 C tolerance is 0 2 C for 5 seconds and the TEC output is turned on the user m
23. END terminator IEEE488 2 standard is being used TERM Notes Examples DEVICE DEPENDENT The TERM query allows the programmer to determine whether the default IEEE488 2 standard terminator has been altered to include a carriage return An altered terminator will be in the form lt CR gt lt NL gt lt END gt This termination will be sent with all output until the TERM 0 command is sent or the LDC 3700C Series Controller is powered off Term response 1 means that the lt CR gt lt NL gt lt END gt terminator is temporarily being used Term response 0 means that the NL END terminator IEEE488 2 standard is being used TIME Notes Examples 132 LDC 3700C Series DEVICE DEPENDENT The TIME query allows the programmer to determine how much time has passed since the LDC 3700C Series Laser Diode Controller was last powered up The TIME clock is independent of the TIMER clock Time response 1 02 36 means that 1 minute and 2 36 seconds have passed since the LDC 3700C Series Laser Diode Controller was powered up TIME response 32 00 76 means that 32 minutes and 0 76 seconds have passed since the LDC 3700C Series Laser Diode Controller was powered up Lightwave COMMAND REFERENCE Command Reference TIMER C DEVICE DEPENDENT The TIMER query allows the programmer to determine how much time has passed since the last TIMER query was issued Notes Ea
24. PARAMETER SET switch to accept the second calibration point After the PARAMETER SET switch is released the LDC 3700C Series Laser Diode Controller will calculate the calibration constants and store them to nonvolatile memory 04 09 LDC 3700C Series 145 CALIBRATION AND TROUBLESHOOTING Calibration Overview Laser Forward Voltage Measurement Calibration The following procedure is for calibrating the LASER voltage measurement Configure the Controller in the following manner for the Laser Controller Voltage calibration Function State Laser Mode constant current low bandwidth Range LDC 3714C 100 mA LDC 3724C 500 mA LDC 3744C 2000 mA Laser Limit set to FS full scale of range Set Point LDC 3714C 60 mA LDC 3724C 400 mA LDC 3744C 400 mA 1 With the LASER output off connect a calibrated voltmeter in parallel with a resistor 100 2 Watt for the LDC 3714C 15 5 Watt for the LDC 3724C or LDC 3744C to the LASER output Laser Anode and Laser Cathode on the rear panel of the controller 2 Pressthe LASER MODE ON switch to turn the LASER output on The LASER output must be on in order to enter the LDV calibration mode 3 Enter the LASER V calibration mode by pushing the Communications LOCAL and LASER DISPLAY V switches at the same time The TEC display will blank and the controller will drive the LASER current output to the respective set point and the LASER display will indicate forward
25. Voltage Limit Condition 512 Output Out of Tolerance Condition 4 N A 1024 Sensor Shorted While Output On Condition 8 High Temperature Limit Condition 2048 N A 16 TEC Interlock Changed Condition 4096 N A 32 Booster Changed While Output On Event 8192 N A 64 Sensor Open While Output On Condition 16384 N A 128 Module Open While Output On Condition 32768 N A Notes The enabled TEC outoff events and conditions which can turn the TEC output off can be set by using the TEC ENABle OUTOFF command Examples TEC ENAB OUTOFF response 258 means that a Sensor Type Change Condition or a Voltage Limit Condition will cause the TEC output to be turned off Radix Hex TEC Enab Outoff response H17FB means that all of the above conditions will cause the TEC output to be turned off Radix Bin TEC Enab Outoff response B1001 means that the High Temperature Limit and TE Current Limit conditions will cause the TEC output to be turned off 04 09 LDC 3700C Series 121 COMMAND REFERENCE Command Reference TEC EVEnt DEVICE DEPENDENT The TEC EVEnt query returns the value of the status event register of the TEC operations 1 TE Current Limit 256 Sensor Type Changed 2 TE Voltage Limit 512 Output Changed to be Out of Tolerance 4 1024 Output On Off Changed 8 High Temperature Limit 2048 New Measurements Taken 16 TEC Interlock Disabled 4096 N A 32 Booster Changed 8192 N A 64
26. 000 to 10 000 V 1 mV 30 mV TEMPERATURE CONTROL NOTES 1 All values after a one hour warm up period at room temperature 25 C 2 Software limits of range Actual range possible depends on the physical load thermistor type and TE module used 3 Accuracy figures are quoted for a typical 10 thermistor and 100 pA current setting Accuracy figures are relative to the calibration standard Both resolution and accuracy are dependent upon the user defined configuration of the instrument Accuracy depends on the sensor model selected the calibration standard and the user defined onfiguration of the instrument 4 5 Over any 1 hour period half scale output controlling an LDM 4412 mount 25 C with 10 thermistor on 100 pA setting 6 Over any 24 hour period half scale output controlling an LDM 4412 mount 25 C with 10 thermistor on 100 pA setting 7 Measured at 1 Amp output over a bandwidth of 10 Hz 10 MHz 8 When ordered with TSC 599 RTD Sensor Converter 9 Nominal temperature coefficients and V apply over the rated IC temperature sensor range 10 Software limits of display range 11 Using 100 thermistor controlling an LDM 4412 mount over 30 C to 25 C 12 Using 10 thermistor controlling an LDM 4412 mount over 30 to 25 13 Voltage measurement accuracy while driving calibration load Accuracy is dependent upon load used General LDC 3700C Specifications
27. 1 Options and Accessories 11 Table 2 1 Laser Error Indicators 28 Table 2 2 SENSOR SELECT Switch Positions 31 Table 2 3 TEC Error Indicators 36 Table 3 1 Substitute Parameter Names 50 Table 3 2 Invalid Syntax Command 5 5 52 Table 3 3 LDC 3700C Commonly Used Commands 54 Table 3 4 Default Settings for Output Off Registers 58 Table 4 1 Remote Command Summary Reference List 64 Table 5 1 Recommended Test Equipment 136 Table 5 2 Required Calibration 138 Table 5 3 Symptoms and Actions 155 Table 5 4 Error Code Classifications 157 Table 5 5 Error Messages 157 04 09 LDC 3700C Series vii TT viii LDC 3700C Series Lightwave 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 which if not avoided could result in death serious or m
28. 406 586 9405 t support ilxlightwave com Or mail to ILX Lightwave Corporation P O 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 or sketch 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 LDC 3700C Series xiii TT container with at least 3 inches 7 5cm of compressible packaging material on all sides We look forward to serving you even better in the future xiv LDC 3700C Series Lightwave CHAPTER 1 INTRODUCTION AND SPECIFICATIONS El mH E El a El El mH El E El H L1 E E E This chapter is an introduction to the LDC 3700C Series Laser Diode Controllers and contains unpacking information instructions on how to install and apply power maintenance information specifications and listings of the LDC 3700C options and accessories Product Overview
29. 488 2 GPIB interface connector is located on the rear panel directly above the power input module and fuse See Figure 1 2 on page 4 Attach the GPIB cable to the 24 pin connector located on the rear panel The connector is tapered to ensure proper orientation Finger 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 LDC 3700C Series Laser Diode Controller are identical This GPIB address is read locally by pressing the GPIB LOCAL switch with the address displayed on the TEC display The controller comes from the factory configured with the GPIB address set to 1 You can change the LDC 3700C s GPIB address locally via front panel A procedure for changing the address can be found in the section Changing the GPIB Address on page 46 Tilt Foot Adjustment The LDC 3700C Series Laser Diode Controller 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 s
30. CAL PD is selected and the display indicates the responsivity parameter in uA MW not annunciated Rotate the adjust knob in the ADJUST section while holding the PARAMETER SET push button to enter a 24 LDC 3700C Series Lightwave 04_09 OPERATIONS Operating from the Front Panel new value for responsivity When the correct value is displayed store the number by releasing the SET push button mmm PARAMETER mm LASER LIM I TE LIM I t C3 LIM THI SELECT LIM I e CONST GO C3 GAIN CAL PD C3 SAVE SET RECALL I To calculate the responsivity 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 pA mW The LDC 3700C Controllers can be put into a special mode with the CAL PD parameter set to zero When the CAL PD value is zero the LASER output will be controlled to the lpp set point value therefore the instrument is in Constant lpp mode The LASER display will indicate in Ppp mode Next configure the display so that it reads in mW by selecting Ppp in the LASER DISPLAY section of the front panel directly underneath the LASER display The LASER DISPLAY switch section is used to select the I laser current Ipp photodiode current Ppp Laser power or V forward voltage measuremen
31. LASER current limit disabled output E 505 LASER voltage limit disabled output E 507 LASER Power limit disabled output E 508 LASER output disabled because of TEC output off condition E 509 LASER output disabled because of TEC High Temperature Limit condition 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 O 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 158 LDC 3700C Series Lightwave CALIBRATION AND TROUBLESHOOTING Troubleshooting Table 5 5 Error Messages Error Code Explanation E 517 Calibration for Laser Diode current must have the output on to start E 518 Calibration for the Monitor Diode must have the output on and the responsivity set to zero to start E 519 Setting a measurement is only valid during the calibration phase for that measurement User has tried to calibrate a measurement without first entering the required calibration mode E 520 User cannot change the Laser Current set point while operating in a calibration mode for another measurement 04 09 LDC 3700C Series 159 CALIBRATION AND TROUBLESHOOTING Troubleshooting 160 LDC 3700C Series Lightwave
32. LIMIT light will also be turned on Output shorted OUTPUT SHORTED light comes on This indicator becomes lit whenever the LASER output is off 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 volts of Voltage Limit If voltage limit is reached the LASER output will shut off Optical Output Power Limit Output off POWER LIMIT light flashes at 1 Hz LDC 3700C Series Lightwave OPERATIONS Operating the TE Controller from the Front Panel Operating the TE Controller from the Front Panel This section describes how to operate your LDC 3700C Series Controller Temperature Controller in Constant Temperature Mode T There are several modes in which you can operate the temperature controller Constant Temperature Constant Resistance Sensor and Constant lg TE module current Operating in Constant Temperature Mode is presented in the following sections however the same operating principles apply to the other operating modes The TEC display The TEC display is used to show TEC control parameter values such as temperature C temperature limit lg limit A thermistor resistance and TE current A measured and set point values It may also display errors which relate to TEC operation Error indicators underneath the TEC display indicate control errors and are explained in the sectio
33. MOT EMPT l OUTPUT ents QUEUE ASE Register I A A 14 N A I A Status Byte Register treet tet STB i 101 0 TEC Event Summary TEC Current Limit LOGICAL OR 4 1901 High Temperature Limit 9 1 I Interlock Disable Booster Enabled TET RET t Service r Status Sun 7 Error Available e Service Reque egister LOGICAL OR QUEUE NET f Ready for Calibration Data ERROR upee F EBRBDPLPEE QUEUE A 0 TEC Current Limit 1 Voltage Limit perature Limi Error LOGICAL OR 9 Tolerar 0 Output On New Measurement Figure 3 5 Status Reporting Scheme 04_09 LDC 3700C Series 57 REMOTE OPERATION Command Syntax Note If the GPIB times out while waiting for a response either set the GPIB time out 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 Output Off Registers The Output Off Enable Registers allow you to determine which conditions and events in the TEC and LASER controllers can cause their outputs to be turned off These registers are configured in a manner which i
34. Module Open While Output On Condition 32768 N A Notes The enabled TEC outoff bits can be read by using the TEC ENABle OUTOFF query The value of the TEC outoff enable register is stored in non volatile memory and is retained at power up The factory default setting for this register is H5E8 or 1512 decimal The High Temperature Limit Condition Sensor Open While Output On Condition and Sensor Type Change While Output On Event bits will not be in effect and will not cause the TEC output to be shut off if the LDC 3700C Series Laser Diode Controller is in ITE mode WARNING If the Output Out of Tolerance Change Event bit is set when the power is off the TEC output will not be able to be turned on until this bit is reset Examples TEC ENAB OUTOFF 9 action enables the TEC status outoff register so that a High LDC 3700C Series Temperature Limit Condition or a TE Current Limit Condition will cause the TEC output to be turned off Tec Enab Outoff H17FB action enables the TEC status outoff register so that any and all of the above conditions will cause the TEC output to be turned off Lightwave COMMAND REFERENCE Command Reference TEC ENABle OUTOFF COMMON DEVICE DEPENDENT FRONT PANE The TEC ENABle OUTOFF query returns the value of the status outoff enable register of the TEC operations things which will turn the TEC output off 1 TE Current Limit Condition 256 Sensor Change While Output On Event 2
35. Over any 1 hour period half scale output Over any 24 hour period half scale output Measured optically evaluating noise intensity of a laser diode into a photodetector with 150 kHz bandwidth Maximum output current transient resulting from normal operational situations e g power on off current on off as well as accidental situations e g power line plug removal Maximum output current transient resulting from a 1000V power line transient spike Maximum monitor photodiode current drift over any 30 minute period Assumes zero drift in responsivity of photodiode 5096 modulation depth at mid scale output Higher bandwidth is possible with smaller modulation signal Responsivity value is user defined and is used to calculate the optical power used LDC 3700C Series Four wire voltage measurement at the load Voltage measurement accuracy while driving calibration load Accuracy is dependent upon load and cable 7 CHAPTER 1 Temperature Controller Specifications INTRODUCTION AND SPECIFICATIONS Temperature Controller Specifications TEMPERATURE CONTROL OUTPUT Temperature Control Range 100 0 C to 199 9 C Thermistor Setpoint Resolution Accuracy 20 C to 20 C 0 1 0 2 20 C to 50 0 2 0 2 AD590 amp LM335 Setpoint 20 C to 50 C 0 1 C 0 1 C Short Term Stability 1 hr lt 0 004 C Long Term Stability 24 hrs lt 0 01 C Outpu
36. Range 0 to 50 mA 0 to 200 mA 0 to 2000 mA 0 to 100 mA 0 to 500 mA 0 to 4000 mA Setpoint Resolution 1 uA 4 uA 40 pA 2 pA 10 pA 80 WA Setpoint Accuracy of FS 0 05 0 05 0 05 Compliance Voltage 0 10V adjustable 0 10V adjustable 0 10V adjustable Temperature Coefficient lt 50 50 ppm C lt 100 ppm C Short Term Stability 1 hour lt 20 ppm lt 20 ppm lt 20 ppm Long Term Stability 24 hours 40 ppm 40 ppm 40 ppm Noise and Ripple uA rms High Bandwidth Mode 1 5 pA 4 uA 15 pA lo range 20 pA hi range Low Bandwidth Mode 1 5 uA 2 UA 10 pA Transients Operational 2 mA lt 3 mA 4 mA 1kV EFT 5 mA 8 mA 10 mA Surge 8 mA 12 mA 8 mA COMPLIANCE VOLTAGE ADJUST Range 0 10V 0 10V 0 10V Resolution 50 mV 50 mV 50 mV Accuracy 2 5 2 5 2 5 DRIVE CURRENT LIMIT SETTINGS Range 0 to 50 5 mA 0 to 202 mA 0 to 2020 mA 0 to 101 mA 0 to 505 mA 0 to 4040 mA Resolution 0 25 mA 1mA 10 mA 0 5 mA 2 5 mA 20 mA Accuracy 0 5 mA 2 mA 20mA 1 mA 5 mA 40 mA PHOTODIODE FEEDBACK Type Differential Differential Differential PD Reverse Bias 0 5 V adjustable 0 5 V adjustable 0 5 V adjustable PD Current Range 5 to 5000 pA 5 to 5000 pA 5 to 10000 pA Output Stability 0 02 0 02 0 02 LDC 3700C Series Lightwave 04_09 INTRODUCTION AND SPECIFICATIONS Laser Current Source Specifications 1 LDC 3714C LDC 3724C LDC
37. Sensor Open 16384 N A 128 TE Module Open 32768 N A Notes The TEC conditions which are reported to the status byte are set via the TEC ENABle EVEnt command The TEC event status is only cleared when the event status is read or a CLS command is issued while the condition status is constantly changing Examples TEC EVE response 513 means that the Output went In or Out of Tolerance and the TE Current Limit events have occurred since the last TEC EVEnt query Radix Hex TEC Event response 44H82 means that the Voltage Limit and TE Module Open events have occurred since the last TEC EVEnt query TEC GAIN OMMON DEVICE DEPENDENT FRONT PANEL The TEC GAIN command sets the TEC control loop gain Parameters nrf value between 1 300 the value will be stored to the nearest of 1 3 10 30 100 or 300 Notes If the user enters a gain value which is greater than 300 a value of 300 will be stored If the user enters a gain value which is less than 1 a value of 1 will be stored If the user enters a value which is not legal the LDC 3700C Series Laser Diode Controller will round that value to the nearest legal value if possible Examples TEC GAIN 100 action the TEC control loop gain is set to 100 Tec gain 3 action the TEC control loop gain is set to 3 TEC Gain 200 action the TEC control loop gain is set to 100 the LDC 3700C Series Laser Diode Controller rounds 200 to the nearest valid number 1
38. Series 29 100A H 10uA SENSOR SELECT THERM N A LM335 AD590 A OPERATIONS _ Operating the TE Controller from the Front Panel through the T temperature R resistance sensor and TE module current instrument operating modes OUTPUT Temperature Controller Sensor Selection Because we have selected a 10 kO thermistor as our temperature sensing element and we have chosen 35 C as our set point temperature we need to set the SENSOR SELECT switch to THERM and the THERM RANGE switch to 100 pA The LDC 3700C s Temperature Controller operates in a closed loop fashion with a temperature sensor being the feedback element For the controller to operate correctly the type of sensor needs to be selected on the rear panel of the instrument The SENSOR SELECT switch allows you to select a temperature sensor type and in the case of a thermistor sensor the source current level For thermistors LM335 and AD590 temperature sensors use the lower switch to select the appropriate sensor type When the sensor switch is changed a sensor position code will be indicated on the TEC display Note Note for RTD sensors the RTD Temperature Sensor Converter option is required ILX Model 599 Table 2 2 shows the SENSOR SELECT positions and corresponding position code Thermistor resistance changes with temperature A constant current source integrated into the controller su
39. Status register If the status of the connection between the BOOSTER PRESENT and DIGITAL GROUND changes this event will also be reported in the TEC Event Status Register These events may be used to trigger a service request 42 LDC 3700C Series Lightwave CHAPTER 3 REMOTE OPERATION 5 B El a El El mH El Hi mH E E The LDC 3700C Series Laser Diode Controller provides both USB and GPIB communications The command set is the same for both communication protocols It is however recommended to only USB or GPIB to the instrument at any given time Simultaneous operation of both protocols is not supported Everything you can 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 set point by a pre defined step value Also you may only query the TEC voltage via remote control The following sections show you the fundamentals of operating your LDC 3700C Laser Diode Controller remotely through the USB or GPIB interface USB Operations To begin using the USB port on the LDC 3700C Series Laser Diode Controller please install the Virtual Com Port Driver which is available on the companion CD or from our website www ilxlightwave com A standard USB A B cable is necessary to connect the instrument to a PC
40. 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 HF9B means that all of the above events will be reported in summarized form to the status byte register bit 2 86 LDC 3700C Series Lightwave COMMAND REFERENCE Command Reference LASer ENABle OUTOFF nrf value DEVICE DEPENDENT The LASer ENABle OUTOFF command sets the status outoff enable register of the LASER operations things which will turn the LASER output off Parameters nrf value whose sum represents the enabled bits 1 LASER Current Limit 256 N A 2 LASER Voltage Limit 512 Output is Out of Tolerance 4 N A 1024 TEC Output Off 8 Power Limit With Output On 2048 TEC High Temperature Limit Condition 16 N A 4096 N A 32 N A 8192 N A 64 N A 16384 N A 128 N A 32768 N A Notes 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 IEEE488 2 specification The factory default value for this register is B0000100000001000 or H808 or 2056 decimal Examp
41. The LASer LIMit 15 query returns the value of the LASER current limit for the 50 mA range on the LDC 3714C or the 500 mA range on the LDC 3724C Not applicable for LDC 3744C Notes The current limit is valid for all modes of Laser operation with respect to the current output range Examples LAS LIM I5 response 400 means the laser current limit is 400 mA LDC 3724C only Laser LIM Ib response 50 means the laser current limit is 50 mA 04 09 LDC 3700C Series 93 COMMAND REFERENCE Command Reference LASer LIMit MDP Parameters Notes Examples DEVICE DEPENDENT FRONT PANEL The LASer LIMit MDP command sets the laser monitor photodiode power limit value An nrf value which represents the laser monitor photodiode power limit in mW When constant MDP mode is used the output is limited only by the LIM I value The LIM MDP condition may be used to shut the LASER output off but this requires the use of the LASer ENABle OUTOFF command to set bit 3 of the LASER OUTOFF ENABLE register LAS LIM MDP 10 action sets the laser output power limit to a value which corresponds to producing 10 00 mW of PD feedback optical power Las Limit MDp 5 action sets the laser output power limit to a value which corresponds to producing 5 00 mW of PD feedback optical power LASer LIMit MDP Notes Examples DEVICE DEPENDENT FRONT PANEL The LASer LIMit MDP query returns the value of the laser monitor P
42. derive temperature from the non linear resistance of an NTC Negative Temperature Coefficient thermistor Linear equations are used to convert sensor voltage or current signals to actual temperature when an LM335 or AD590 sensor is used See the TEC Specifications in Chapter 1 for these equations When CONST is selected in the TEC PARAMETER section of the front panel the constant s name will be displayed on the LASER display and the value will be displayed on the TEC display LASER 2347 2 TEMPLIMIT TE CURRENT LIMIT O INTERLOCK VOLTAGELIMIT CURRENT LIMIT SENSOROPEN TEMODULE OPEN OPENCIRCUIT CJ OUTPUT SHORTED LJ POWERLIMIT To adjust the value of C1 C2 or C3 press the PARAMETER SELECT button until it sequences to CONST on the TEC side The CONST indicator will be illuminated The LASER display will read C1 and the value will be displayed on the TEC display To change the value press and hold in the SET switch and turn the ADJUST knob until the correct value is displayed Release the SET switch to store the new value Pressing the SELECT push button will toggle through each constant C1 C2 and C3 When C3 is not used it should be set to zero TEC mE PARAMETER m LASER LIM I TE Li UMI Oo LIM THI UMI CONST LMP GAIN CAL PD c SAVE RECALL C3 Da The ILX Lightwave Application Note 17 contains information on sensor calibration constants for AD
43. for some twisted pair wires There are eight data input output IO lines three handshake lines and five interface management lines Eight data input output DIO lines carry both data including device dependent commands and interface messages The ATN interface management line determines whether these lines contain data or interface messages Three handshake lines ensure that all data and messages are reliably transferred NRFD not ready for data indicates whether a device can receive the next byte of data or message NDAC not data accepted indicates whether a receiving device has accepted a byte of data or message DAV data valid indicates that the signal levels on the data lines are stable and available for the receiving device s to accept Five interface management lines control the flow of information attention is set by the controller in charge to define the I O lines for data or interface messages IFC interface clear is set by the system controller to initialize the bus and assert itself as controller in charge REN remote enable is set by the controller to place addressed devices into remote or local front panel control mode SRQ service request can be set by any device in the system to request service from the controller LDC 3700C Series 45 REMOTE OPERATION Basic GPIB Concepts EOI end or identify is used by talkers to identify the end of a message DIO1 DIO
44. has the same results Tec CAL V response 1 means the LDC 3700C Series Laser Diode Controller is ready for the user to enter a resistance value via the TEC V command Tec Cal v response 0 means the LDC 3700C Series Laser Diode Controller is not yet ready for the user to enter a voltage value Lightwave COMMAND REFERENCE Command Reference TEC COND DEVICE DEPENDENT The TEC COND query returns the value of the status condition register of the TEC operations 1 TE Current Limit 256 N A 2 Voltage Limit Error 512 Output Out of Tolerance 4 N A 1024 Output On 8 High Temperature Limit 2048 Ready for Calibration Data 16 TEC Interlock Enable 4096 N A 32 Booster Enable 8192 N A 64 Sensor Open 16384 N A 128 TE Module Open 32768 N A Notes The enabled TEC conditions can be set by using the TEC ENABle COND command The TEC 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 TEC COND response 513 means that the Output Out of Tolerance and TE Current Limit TEC conditions currently exist Radix Hex TEC Cond response H82 means that the TE Module Open and Voltage Limit TEC conditions currently exist TEC CONST DEVICE DEPENDENT FRONT PANEL The TEC CONST command sets the TEC s Steinhart Hart equation constants Parameters One two or three nrf values for the three
45. has exceeded the limit set point 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 LDC 3700C Series instruments have an adjustable laser compliance voltage Check to see if the LASER voltage limit setting is too low see Chapter 2 Check laser connections TE Controller Power on but no TE current output If TE MODULE OPEN indicator is lit check the load connections Check that pins 14 and 15 of the output connector are not connected See Boosting the TE Controller on page 41 Power on but temperature is not controlled If SENSOR OPEN indicator is lit check the sensor connections Check that the rear panel SENSOR SWITCH position is set for the proper sensor type Check that C1 and C2 and C3 are correct values for your temperature sensor Check that the GAIN setting is not too low and that the LIM lyg value is not too low for your thermal load Unable to adjust output or parameter Check the ADJUST TEC indicator the indicator must be lit for a
46. may be ignored for these cases TEC CONST response 1 111 2 03 0 85 means C1 1 111 C2 2 030 and 0 850 TEC Const response 1 00 2 222 0 07 means C1 1 000 C2 2 222 and C3 0 070 TEC DISplay Parameters Notes Examples DEVICE DEPENDENT FRONT PANEL The TEC DISplay command enables or disables turns off the TEC display and TEC section s indicator LEDs An nrf value 1 on 0 off Turning the TEC display and LEDs off means that a message of all blank spaces is sent to the TEC display and all of the TEC section s indicator LEDs will be turned off TEC DIS 0 action the TEC display will be blanked and all of the TEC indicator LEDs will be turned off tec dis 1 action the TEC display and LEDs will be enabled tec display on action the TEC display and LEDs will be enabled TEC DISplay Notes Examples 112 LDC 3700C Series DEVICE DEPENDENT FRONT PANEL The TEC DISplay query returns the contents of the TEC display Returns the actual 6 character string from the output buffer to the TEC display If the display is disabled it returns TEC DIS response 99 9 means 99 9 is on the TEC display Tec DISp response 0 6 means 0 6 is on the TEC display Lightwave COMMAND REFERENCE Command Reference TEC DISplay ITE DEVICE DEPENDENT FRONT PANEL The TEC DISplay ITE command enables the TEC display to show the TE current m
47. milliseconds between steps The decremental default amount is one step The step size can be edited via the LAS STEP command LDC 3714C default values are 0 001 0 002 mA 50 100 mA range 0 01 mW or 1 uA if CALMD 0 depending on the mode of operation LDC 3724C default values are 0 01 mA 0 01 mW or 1 pA LDC 3744C default values 0 1 mA 0 1 mW or 1 PA If the first optional parameter is used but not the second the LASER set point is incremented by a multiple of the LAS STEP size without changing the LAS STEP size The second optional parameter is the time in msec 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 about 20 msec Therefore values for the second optional parameter time between increments have a practical minimum of 20 LAS MODE I LAS STEP 3 LAS INC action The laser source current set point is incremented by 0 3 mA LDC 3744C or 0 03 mA LDC 3724C or 0 003 mA LDC 3714C on 50 mA range or 0 006 mA LDC 3714CCon 100 mA range LAS MODE I LAS STEP 3 LAS INC 3 action The laser source current set point 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 set point is incremented by the am
48. the high temperature condition is also used to turn the TEC output off see TEC ENABle OUTOFF Examples TEG LIM Thi response 30 5 means the TEC load s high temperature limit is 30 5 C Tec Limit THI response 184 7 means the TEC load s high temperature limit is 184 7 C TEC MODE C r DEVICE DEPENDENT FRONT PANEL The TEC MODE query returns the selected TEC control mode Notes The TEC mode is also the parameter which is controlled The TEC output is kept at the set point Examples Tec MODE response ITE means that constant ITE current mode is in effect for the TEC output TEC Mode response R means that constant R resistance reference mode is effect for the TEC output Tec Mode response T means that constant T temperature mode is in effect for the TEC output TEC MODE ITE DEVICE DEPENDENT FRONT PANEL The TEC MODE ITE command selects TEC constant TE current mode Parameters None Notes This mode keeps the TEC current constant regardless of load temperature variations Changing modes causes the output to be forced off and the new mode s set point value will be dis played Examples TEC MODE ITE action sets the TEC controller for constant TEC current operation Tec Mode lte action sets the TEC controller for constant TEC current operation 04 09 LDC 3700C Series 7 125 126 COMMAND REFERENCE Command Reference TEC MODE R Parameters Notes Examples
49. 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 LDC 3700C Series Laser Diode Controller is ready to receive it The Controller will be ready to receive the new measured value when after a LAS CAL LDI query is sent the response from the Controller is 1 6 Once the newly measured value is entered via the LAS LDI command the Controller will apply a new current equal to about 25 of the previous set current 7 Input the second actual measured LASER output current as an lt nrf value asin Step 5 8 Once the second actual I 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 LDC 3700C Series Laser Diode Controller will also perform current limit calibrations for and P modes 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 9 Change the Laser Mode to lugw high bandwidth constant current mode with the LAS IHBW command Repeat the calibration procedure as described above 152 LDC 3700C Series Lightwave CALIBRATION AND TROUBLESHOOTING Calibration Overview 1 Current Calibration The following procedure is for calibrating the LASER lp constant current source This procedure calibrates the feedback c
50. voltage may be displayed LASer DISplay IDP N MDI DEVICE DEPENDENT FRONT PANEL The LASer DISplay MDI command sets the laser display to show the monitor photodiode current measurement Parameters None Notes The actual LASER DISPLAY lp display is turned off automatically when another LASER DISPLAY selection is enabled Examples LAS DIS MDI action enables the LASER display for photodiode current values Laser Disp Mdi action enables the LASER display for photodiode current values LASer DISplay IDP gt MDI DEVICE DEPENDENT FRONT PANEL The LASer DISplay MDI query returns the status of the LASER DISPLAY lpo switch Notes In local operation the status of the lpp switch is indicated by the enunciator next to the LASER display pA will be illuminated when the display is Ipp mode Examples LAS DIS MDI response 0 means that the LASER DISPLAY lp switch is not currently active laser photodiode monitor current is not displayed Las dis MDI response 1 means that the LASER DISPLAY lpp switch is currently active monitor PD current may be displayed 80 LDC 3700C Series Lightwave COMMAND REFERENCE Command Reference LASer DISplay PPD C MDP DEVICE DEPENDENT FRONT PANEL The LASer DISplay MDP command sets the laser display to show the monitor photodiode power measurement Parameters None Notes The actual LASER display is turned off automatically when another LA
51. 000 mA range on the LDC 3744C Not applicable for LDC 3724C or LDC 3714C This command is for compatibility with programs written for the LDC 3742C An nrf value which represents the LASER limit current in mA The current limit is in effect in all modes of operation of the laser output and the respective output range LAS LIM I3 800 action the LASER current limit is set to 800 mA Laser Limit l3 2600 action the LASER current limit is set to 2600 mA LASer LIMit I3 Notes Examples LASer LIMit I4 Parameters Notes Examples 92 LDC 3700C Series DEVICE DEPENDENT FRONT PANEL The LASer LIMit 13 query returns the value of the LASER current limit for the 4000 mA range on the LDC 3744C Not applicable for LDC 3724C or LDC 3714C The current limit is valid for all modes of Laser operation LAS LIM I3 response 400 means the laser current limit is 400 mA LDC 3744C only Laser LIM I3 response 1500 means the laser current limit is 1500 mA LDC 3744C only DEVICE DEPENDENT FRONT PANEL The LASer LIMit 14 command sets the LASER current limit value for the 4000 mA range on the LDC 3744C Not applicable for LDC 3724C or LDC 3714C An nrf value which represents the LASER limit current in mA The current limit is in effect in all modes of operation of the laser output and the respective output range LAS LIM 14 800 action the LASER current limit is set to 800 mA Laser Limit 14 2600
52. 00C Series 41 ys OPERATIONS Functions and Features All functions of the temperature controller can be utilized as in normal TEC operation with the exception of the TE Current Limit When the controller is configured in BOOSTER MODE the LIM I value may be increased above the normal operating maximum of 4 0 Amps to a maximum of 10 0 Amps The control signal voltage 10 V is linearly proportional to the control current which is limited by the LIM I parameter Pins 11 and 12 are outputs from the TEC controller hardware These lines are TTL level indicators of the TEC voltage and limit conditions respectively They are useful for external sensing of these conditions in addition to the normal status reporting of the LDC 3700C Series instrument Pin 13 is used as an external shutoff switch Although it is labeled as Temp Limit its function is to shut off the TEC controller This function is controlled by applying a TTL level signal to pin 13 When this input is high the LDC 3700 Series instrument will shut the TEC controller off The feedback loop GAIN will require adjustment when a booster current source is used The higher thermal loads will require larger or smaller GAIN values in order to settle to the set temperatures in a desirable fashion See Setting TE Control Loop Gain in Chapter 2 For remote operation using the GPIB interface during controller operation the Booster Enabled condition is reported in the TEC Condition
53. 024 Output On Off Changed 8 High Temperature Limit 2048 New Measurements Taken 16 TEC Interlock Disabled 4096 N A 32 Booster Enable 8192 N A 64 Sensor Open 16384 N A 128 TE Module Open 32768 N A Notes The enabled TEC events can be set by using the TEC ENABle EVEnt command The TEC event status can be read and reset by issuing the TEC EVEnt query Examples TEC ENAB EVE response 520 means that the High Temperature Limit and Output Out of Tolerance TEC events will be reported in summarized form to the status byte register bit 0 Radix Hex TEC Enab Eve response HOEFB means that all of the above events will be reported in summarized form to the status byte register bit O 04 09 LDC 3700C Series 7 119 120 COMMAND REFERENCE Command Reference TEC ENABle OUTOFF DEVICE DEPENDENT The TEC ENABle OUTOFF command sets the status outoff enable register of the TEC operations things which will turn the TEC output off Parameters nrf value whose sum represents the enabled bits 1 TE Current Limit Condition 256 Sensor Change While Output On Event 2 Voltage Limit Condition 512 Output Out of Tolerance Condition 4 N A 1024 Sensor Shorted While Output On Condition 8 High Temperature Limit Condition 2048 N A 16 TEC Interlock Changed Condition 4096 N A 32 Booster Changed While Output On Event 8192 N A 64 Sensor Open While Output On Condition 16384 N A 128
54. 1 LASER Voltage Limit 9 LASER Output Changed to be out of Tolerance 2 N A 10 TEC Output is Off Event 3 LASER Power Limit output on 11 TEC High Temperature Limit Condition 4 N A 12 N A 5 N A 13 N A 6 N A 14 N A 7 N A 15 N A 7 16 5 4 3 2 1 Jo TEC Output Off Register Logical OR TEC Output Off Enable Register Turn Output Off TEC ENABle OUTOFF lt nrf gt TEC ENABle OUTOFF Figure 3 7 TEC Output Off Register LDC 3700C Series 59 REMOTE OPERATION Command Syntax Bit Reference 0 TEC Current Limit 8 Sensor Type Change while output on Eve 1 TEC Voltage Limit 9 Outside of TEC Tolerance Cond 2 N A 10 Sensor Shorted while output on Cond 3 High Temperature Limit 11 N A 4 N A 12 N A 5 Booster Changed while output on Eve 13 N A 6 Sensor Open while output on Cond 14 N A 7 TEC Module Open output on Cond 15 N A 60 LDC 3700C Series Lightwave REMOTE OPERATION Command Syntax Command Timing 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 this command is being executed or if the next command must wait until this command is completed before its execution begins See Operation Complete Defini
55. 17 Setting the PD bias Lus eec ace cae d enc i 18 Grounding Considerations 18 Connecting to the TE Controller 19 TEC Grounding 5 5 19 Operating from the Front Panel 20 The Laser Controller Display 20 Operating a Laser in Constant Current I Mode 20 Set Up the 2 4 20 set the Range inis kr nde eee ee ko leie 21 Select the Laser Display 21 Adjusting the Set Point 21 Set Current Source Limit 22 Set Compliance Voltage Limit 23 Automatic Shutoff Conditions for Laser Output 24 Operating a Laser in Constant Power Mode P 24 Entering Photodiode Responsivity values 24 LASER Error Indicators 28 Operating the TE Controller from the Front Panel 29 The TEC display sse etre TERR 29 Operating the Controller in Temperature Mode 29 Setting up the Temperature Controller 29 Tempera
56. 227 LDC 3700C Series Lightwave COMMAND REFERENCE Command Reference TEC GAIN C DEVICE DEPENDENT FRONT PANEL The TEC GAIN query returns the value of the control loop gain Notes If a value other than 1 3 10 30 100 or 300 is entered via the GAIN command the nearest valid value will be stored Examples TEC Gain response 30 0 means the control loop gain is set to 30 Tec GAIN response 100 0 means the control loop gain is set to 100 TEC ITE DEVICE DEPENDENT FRONT PANEL The TEC ITE command sets the TEC control current set point It is also used to enter the TEC current calibration value Parameters An nrf value which represents the ITE set point current in Amps In ITE current calibration mode the nrf value represents the measured current value in Amps Notes This set point is used by the TEC s constant ITE mode only In local operation the ITE set point is entered by selecting ADJUST TEC and ITE modes pressing the TEC DISPLAY SET switch adjusting the ADJUST knob within 3 seconds and then releasing the SET switch when the desired value is shown on the TEC display Examples TEC ITE 1 action sets the TEC output current set point to 1 000 Amps TEC MODE ITE Tec lte 3 5 action sets the TEC output current set point to 3 500 Amps and the output is controlled to that value TEC ITE l DEVICE DEPENDENT FRONT PANEL The TEC ITE query returns the value of the measured TEC
57. 3744C Accuracy setpoint 96 of FS 0 05 0 05 0 05 EXTERNAL ANALOG MODULATION Input 0 10 V 1 0 10 V 1 0 10 V 1 ka Transfer Function 5 mA V 20 mA V 200 mA V 10 mA V 50 mA V 400 mA V Bandwidth 3 dB High Bandwidth DC to 1 MHz DC to 1 MHz DC to 250kHz Low Bandwidth DC to 15 kHz DC to 15 kHz DC to 10 kHz TRIGGER OUTPUT Type TTL TTL TTL Pulse Width 13 us 13 us 13 us Delay 12 ms 12 ms 12 ms MEASUREMENT DISPLAY Output Current Range 0 to 50 000 mA 0 to 100 00 mA 0 to 200 00 mA 0 to 500 00 mA 0 to 2000 0 mA 0 to 4000 0 mA Output Current Resolution 0 001 mA 0 01 mA 0 1 mA Output Current Accuracy 0 05 FS 0 05 FS 0 1 FS Photodiode Current Range 0 to 5000 pA 0 to 5000 pA to 10000 LA Photodiode Current Resolution 1 pA 1 pA 1 uA Photodiode Current Accuracy 2 uA 2 uA 4 uA PD Responsivity Range UA mW 0 00 to 1000 00 0 00 to 1000 00 0 00 to 1000 00 PD Responsivity Resolution UA MW 0 01 for all product ranges Optical Power Range mW 0 00 to 100 00 0 00 to 500 00 0 00 to 5000 0 Optical Power Resolution MW 0 01 0 01 0 1 Forward Voltage Range V 0 000 to 10 000 0 000 to 10 000 0 000 to 10 000 Forward Voltage Resolution 1 mv 1 mv 1 mv Forward Voltage Accuracy 0 2 mV 2 mV 2 mV LASER CURRENT SOURCE NOTES 1 All values after a one hour warm up period at room temperature 25 99 gom
58. 5 DIO2 DIO6 DIO3 DIO7 DIO4 DIO8 EOI REN DAV GND Twisted pair with DAV NRFD GND Twisted pair with NRFD NDAC GND Twisted pair with NDAC IFC GND Twisted pair with IFC SRQ GND Twisted pair with SRQ ATN GND Twisted pair with ATN SHIELD SIGNAL GROUND Figure 3 2 GPIB Connector Diagram Reading the GPIB Address Before you can operate the LDC 3700C from a remote location you need to know its GPIB address Simply press the LOCAL switch in the section labeled GPIB on the front panel The instrument will display the address on the TEC display 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 LDC 3700C Series Laser Diode Controller at this time GPIB REMOTE EJ TALK LISTEN LOCAL 46 LDC 3700C Series Lightwave REMOTE OPERATION Changing Operation from Local to Remote Changing Operation from Local to Remote Sending a command over the GPIB bus or USB automatically puts the instrument in REMOTE mode The REMOTE indica
59. 590 and LM335 sensors Since these devices are LDC 3700C Series 31 OPERATIONS Operating the TE Controller from the Front Panel used over their linear range the constants C1 and C2 are used in this case to determine a linear approximation of the temperature rather than the Steinhart Hart non linear approximation which applies for thermistors The appropriate algorithms are automatically implemented whenever the sensor type is selected via the rear panel SENSOR SELECT switch Setting TE Control Loop Gain For best temperature control loop performance the control loop gain needs to be set The GAIN function sets the analog feedback gain which in part determines how fast the actual temperature reaches and settles to the set point temperature If the gain is set too low 1 is lowest the TE cooler will take longer to reach the temperature set point If it is set too high 300 is highest the actual temperature may overshoot and may oscillate around the set temperature resulting in long temperature settling times The allowed GAIN values in the LDC 3700C s Temperature Controller are 1 3 10 30 100 and 300 These values define the proportional loop gain of our hybrid P I temperature control loop The gain setting depends on the type of TE module and thermal load that you are using but we can suggest guidelines for selecting the proper gain Set the gain to 1 and increase it until the actual temperature oscillates around the set te
60. A and the second represents the time window in seconds with a range of 0 001 to 50 000 seconds Notes The LDC 3700C Series Laser Diode Controller defaults to a tolerance of 10 0 mA for 5 seconds unless changed by the LASer TOLerance command If the LDC 3700C Series Laser Diode Controller is operated in P mode the current tolerance parameter is not used Instead a fixed value of 50 uA is used for the lpo current A fixed value of 10 mW LDC 3744C or 1 mW LDC 3714C or LDC 3724C is used for Pp power and only the time window parameter may be adjusted If the tolerance is set too tight it may never be achieved This is due to the calibration of the set point and measurement values Examples Las Tol 0 5 10 action the LDC 3700C Series Laser Diode Controller s LASER current source will be in tolerance when the LASER current is within 0 5 mA for 10 000 seconds 04 09 LDC 3700C Series 101 COMMAND REFERENCE Command Reference LASer TOLerance DEVICE DEPENDENT The LASer TOLerance query allows the programmer to determine how the LASER current tolerance is set Notes The tolerance of the LDC 3700C Series Laser Diode Controller LASER current may be used to delay programming after an LASer OUTput 1 command is issued or the set point 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 r
61. A 4 point resistance measurement is recommended 3 Press the LASER MODE ON switch to turn the LASER output on Verify proper operation i e the lpp set point should be close and the unit should not be in current limit 4 Press the Communications LOCAL and LASER DISPLAY I switches at the same time to place the Controller in its Ipp Current Calibration mode After a few seconds the LASER display will show the lpp set point value 5 After the value on the LASER display is stable has not changed by more than one digit for several seconds the LDC 3700C Series Laser Diode Controller 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 LASER display shows the actual monitor current as shown on the calibrated ammeter or the calculated lpp value from Step 2 144 LDC 3700C Series Lightwave CALIBRATION AND TROUBLESHOOTING Calibration Overview 6 Release the PARAMETER SET switch to store the first calibration value into non volatile memory The controller will then set the second calibration current approximately one fourth 1 4 of the original current For example if the first calibration set point was 4000 the second set point will be about 1000 pA 7 Press and hold in the PARAMETER SET switch and turn the ADJUST knob until the LASER display indicates the actual current as measured by the ammeter or as calculated 8 Release the
62. AS MDI 1 Used to set the constant optical power set point if PD responsivity is 0 LAS MDI NONE Used to return the monitor PD current measured value LAS MDP 1 Used to set the constant optical power set point LDC 3700C Series 65 4 4 COMMAND REFERENCE Remote Command Reference Summary Table 4 1 Remote Command Summary Reference List Name Parameters Function LAS MDP NONE Returns the actual monitor PD power value LAS MODE NONE Returns the mode current IHBW high bandwidth or P optical power LAS MODE IHBW NONE Sets the mode to constant current high bandwidth 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 LAS RAN NONE Returns the laser current output range LAS SET LDI NONE Returns the laser constant I current set point LAS SET MDI NONE Returns the laser constant optical power set point LAS SET MDP NONE Returns the constant P optical power set point LAS STEP 1 Used to set the LASER set point step value LAS STEP NONE Returns the LASER set point step value LAS TOL 2 Used to set the LASER set point tolerance va
63. C Series Lightwave COMMAND REFERENCE Command Reference LASer CAL LDI C I DEVICE DEPENDENT FRONT PANEL The LASer CAL LDI query is used to determine that the LDC 3700C Series Laser Diode Controller is ready for a value to be entered during the calibration cycle of the LASer CAL LDI mode Notes After this query is issued and a response of 1 is received the LDC 3700C Series Laser Diode Controller 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 LDC 3700C Series Laser Diode Controller is ready for the user to enter a current value via the LASer LDI command LASer CAL LDV DEVICE DEPENDENT The LASer CAL LDV command is used to enter the LASER voltage measurement calibration mode Parameters None Notes After this command is issued the LDC 3700C Series Laser Diode Controller will allow calibration of the laser voltage measurement The LASer CAL LDV query may be used to determine if the LDC 3700C Series Laser Diode Controller is ready for the user to enter a value Examples Las CAL Ldv action the LDC 3700C Series Laser Diode Controller enters calibration mode for LASER voltage Las Cal LDV action the LDC 3700C Series Laser Diode Controller enters calibration mode for LASER voltage LASer CAL LDV DEVICE DEPENDENT The LASer CAL LDV query is used to determine that the LDC 3700C Series Laser Diode Contro
64. CAL ITE command to place the controller in TEC Current Calibration mode The TEC display indicates a small current in Amps as the temperature controller calibrates itself for a zero current level After 20 seconds the TEC controller drives the output to 2 000 amps Once stable the temperature controller is ready to enter the actual TE current value 5 Enterthe TE current value using the TEC ITE nrf value command The absolute value of the actual ITE value is the lt nrf value The controller drives the TE output current to the negative value of 2 000 Amps 6 Repeat step 5 for the negative polarity of the TEC output current After the negative polarity value of the TEC output is entered the controller automatically calibrates its current limits and set points indicated by the flashing TE Current Limit indicator The controller then returns to the state before calibration 04 09 LDC 3700C Series 149 CALIBRATION AND TROUBLESHOOTING Calibration Overview TEC Voltage Calibration The following procedure is for calibrating the TEC voltage measurement This procedure calibrates the positive and negative voltages in one procedure Note The TEC Voltage calibration may only be performed remotely 1 With the output off connect a 50 O 5 W resistor across the TEC output terminals TE Module and TE Module 2 Connect a calibrated DMM across the load resistor Enter the TEC ITE 0 command t
65. D power limit The LASER MDP limit is in effect for both laser output current ranges LAS LIM MDP response 3 0 means the monitor PD power limit is set to 3 0 mW LAS Limit MDP response 10 0 means the monitor PD power limit is set to 10 0 mW LASer LIMit V Parameters Notes Examples 94 3700 Series DEVICE DEPENDENT FRONT PANEL The LASer LIMit V command sets the LASER compliance voltage limit value An lt nrf value which represents the LASER limit voltage in volts 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 LIM parameter pressing and holding in the PARAMETER SET switch and then pressing the LAS DISPLAY V switch Turn the ADJUST knob until the desired value is displayed and then release the SET switch LAS LIM V 5 0 action the LASER compliance voltage limit is set to 5 0 volts Laser Limit V 4 60 action the LASER compliance voltage limit is set to 4 6 volts Lightwave COMMAND REFERENCE Command Reference LASer LIMit V C DEVICE DEPENDENT FRONT PANEL The LASer LIMit V query returns the value of the LASER compliance vo
66. DE T Missing colon MODE expected EC MODE R 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 52 7 LDC 3700C Series Lightwave REMOTE OPERATION Command Syntax IEEE488 2 Common Commands The IEEE488 2 Common Commands and Queries are distinguished by the which begins each mnemonic The diagrams below show the syntax structure for common commands common command queries and common commands with numeric data required Common Command Common Command Query Numeric Program Data white Space Common Command with Numeric Data Figure 3 4 Common Command Diagrams Numeric data is required with PSC 1 on 0 off RCL 0 to 10 see front panel RECALL function SAV 1 to 10 see front panel SAVE function 1 ESE 0 to 255 see Figure 3 2 SRE 0 to 255 see Figure 3 2 and PUD used at factory only A list of all of the IEEE 488 2 Common Commands supported by the LDC 3700C CAL CLS ESE ESE ESR IDN OPC OPC PSC PSC PUD PUD RCL RST SAV SRE SRE STB TST WAI See the Command Reference on page 69 for descriptions of all the including common commands supported by the LDC 3700C commands 04 09 LDC 3700C Series 53 REMOTE
67. Diode Controller is not yet ready for the user to enter a resistance value 04 09 LDC 3700C Series 109 110 COMMAND REFERENCE Command Reference TEC CAL V COMMON Parameters Notes Examples DEVICE DEPENDENT The TEC CAL V command enters the calibration mode for TEC voltage measurement None After this command is issued the front panel is disabled and the LDC 3700C Series Laser Diode Controller will automatically enter the TEC voltage calibration mode When the LDC 3700C Series Laser Diode Controller is ready the user should enter the true measured value This procedure is outlined in Chapter 6 The TEC CAL V query may be used to determine if the LDC 3700C Series Laser Diode Controller is ready for the user to enter a value Tec CAL V action the LDC 3700C Series Laser Diode Controller enters TEC voltage measurement calibration mode TEC CAL V Notes Examples LDC 3700C Series DEVICE DEPENDENT The TEC CAL V query is used to determine that the LDC 3700C Series Laser Diode Controller is ready for a value to be entered during the calibration cycle of the TEC CAL V mode This query can be used to poll the LDC 3700C Series Laser Diode Controller after the TEC CAL V command to determine if it is waiting for a value If the response is 1 the LDC 3700C Series Laser Diode Controller is ready to receive a calibration value via the TEC V command Chapter 6 A query of the TEC condition status register bit 11
68. 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 pho todiode monitor current is not controlling the laser output current LASer MODE Notes Examples LDC 3700C Series DEVICE DEPENDENT FRONT PANEL LASer MODE query returns the selected laser control mode lg mode is the same as mode low bandwidth except that the output low bandpass filter is dis abled in mode 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 Laser MODE response IHBW means that constant ls current high bandwidth mode is in effect for the laser output Lightwave COMMAND REFERENCE Command Reference LASer MODE IHBW COMMON DEVICE DEPENDENT FRONT PANEL The LASer MODE IHBW command selects laser high bandwidth constant current mode Parameters None Notes This mode of operation is constant mode with the output lowpass filter disabled Examples LAS Mode lhbw action enables the laser high bandwidth constant current mode LASer MODE ILBW COMMON DEVICE DEPENDENT FRONT PANEL The LASer MODE ILB
69. MMAND REFERENCE Command Reference TEC DISplay R DEVICE DEPENDENT FRONT PANEL The TEC DISplay R command sets the TEC display to show the thermistor resistance AD590 current or LM335 voltage measurement Parameters None Notes The actual TEC R display is turned off automatically when another TEC display selection is enabled Examples TEC DIS R action enables the TEC display for measured resistance or linear sensor reference values TEC Display R action enables the TEC display for measured resistance or linear sensor reference values TEC DISplay R JOMMON DEVICE DEPENDENT FRONT PANEL The TEC DISplay R query returns the status of the TEC DISPLAY R switch Notes The response will be the status of the TEC DIS R switch 1 on 0 off Examples TEC Dis R response 0 means that the TEC DIS R switch is not active Therefore TEC thermistor resistance or AD590 current or LM335 voltage is not displayed Tec dis R response 1 means that the TEC DIS R switch is active Therefore TEC thermistor resistance or AD590 current or LM335 voltage may be displayed TEC DISplay SET OMMO DEVICE DEPENDENT FRONT PANEL The TEC DISplay SET command sets the TEC display to show the currently selected mode s set point value Parameters None Notes Using this command has the same effect as physically holding the TEC DISPLAY SET switch down in Examples Tec Dis Set action enables the TEC display for the set point of the select
70. N User s Guide Laser Diode Controller LDC 3700C Series COMMUNICATIONS TEG DISPLAY LASER DISPLA r 2 74 D T X i 6 5 POWER MODE PARAMETER LASER MODE RANGE o 0 c Li DE NEA EE 5 5 pr u cA LI db IL Lis vane 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 70041001 April 2009 TABLE OF CONTENTS EH El m E E E i i E El Safety Information and the ix General Safety 5 5 ix Safety Marking Symbols X Limitations eden RE Rd Rus stk xi Returning an Instrument xi Claims for Shipping Damage xii Comments Suggestions and Problems xiii Chapter 1 Introduction and Specifications Product Overview 1 Initial Inspection 1 Installing the LDC 3700C
71. NE Returns the value of the TEC event enable register TEC ENAB OUTOFF 1 Sets the enable register for TEC conditions which turn the TEC output off TEC ENAB OUTOFF NONE Returns the value of the TEC outoff enable register TEC EVENT NONE Returns the value of the TEC event register TEC GAIN 1 Used to set TEC control loop gain parameter TEC GAIN NONE Used to return the TEC control loop gain parameter TEC ITE 1 Used to set the TEC current ITE set point TEC ITE NONE Returns the measured TEC current ITE value TEC LIM ITE 1 Used to set the TEC constant current source limit value TEC LIM ITE NONE Used to return the TEC constant current source limit value TEC LIM THI 1 Used to set the TEC upper temperature limit value TEC LIM THI NONE Returns the TEC upper temperature limit value TEC MODE NONE Returns the mode ITE TEC current R sensor or T temperature TEC MODE ITE NONE Sets the mode to constant TEC current mode TEC MODE R NONE Sets the mode to constant thermistor resistance linear sensor reference mode TEC MODE T NONE Sets the TEC mode to constant temperature mode LDC 3700C Series 67 68 COMMAND REFERENCE Remote Command Reference Summary Table 4 1 Remote Command Summary Reference List Name Parameters Function TEC OUT 1 Used to enable disable the TEC current output TEC OUT NONE Returns the TEC OUTPUT status TEC R 1 Set
72. ONT PANEL The TEC CAL ITE query is used to determine that the LDC 3700C Series Laser Diode Controller is ready for a value to be entered during the calibration cycle of the TEC CAL ITE mode Notes This query can be used to poll the LDC 3700C Series Laser Diode Controller after the TEC CAL ITE command to determine if its waiting for a value If the response is 1 the LDC 3700C Series Laser Diode Controller is ready to receive a calibration value via the TEC ITE command see Section 6 3 8 This query may then be repeated for the second half of the calibration cycle A query of the TEC condition status register bit 11 has the same results Examples Tec CAL ITE response 1 means the LDC 3700C Series Laser Diode Controller is ready for the user to enter a current value via the TEC ITE command Tec Cal lte response 0 means the LDC 3700C Series Laser Diode Controller is not yet ready for the user to enter a current value or it is not in the TEC current calibration cycle 108 LDC 3700C Series Lightwave COMMAND REFERENCE Command Reference TEC CAL SENsor C DEVICE DEPENDENT FRONT PANEL The TEC CAL SENsor command sets the TEC s sensor calibration mode for the activated via the rear panel switch sensor and it enters that mode Parameters None Notes After this command is issued the front panel is disabled and the LDC 3700C Series Laser Diode Controller will automatically enter the sensor calibration mode When t
73. OPERATION Command Syntax This structure is illustrated in Figure 3 3 Table 4 1 on page 64 lists all of the LDC 3700C device dependent commands with the full path shown for each command and a brief explanation of its usage I root com z de aaah LAS TEC CAL MES SS ee Mo e CLS MES CALMD CAL DIS ENAB LIM MODE SET COND CAL DIS ENAB SET ESE RAD CALMD CONST ESE RAD COND CONST ESR SECURE DEC CONST LDI 1 IHBW LDI DIS CONST ITE COND ITE ITE IDN TERM PIS LDI LDI COND 11 ILBW MDI DIS 1 COND ITE R R OPC TERM DIS LDI 10 EVE 12 MDP MDP EVE 1 R THI T OPC TIME EVE LDV LDV EVE 212 GAIN SEN R PSC TIMER INC 10 MDI OUTOFF 13 GAIN SEN 5 OUTOFF PSC 101 MDI QUTOFF 13 we SET OUTOFF PUD LDI MDI MDP 14 ITE M TT PUD LDV MDP 14 MODE T RCL LDV SET 45 OUT RST MDI SET 157 OUT SAV MDI PARAM MDP R SRE MDP MDP R SRE MDP SEN STB MODE did T TST OUT WAI OUT TOL RAN TOL RAN x STEP STEP TOL TOL I LDC 3714C and LDC 3744C only I2 LDC 3724C only LDC 3744C only 14 LDC 3744C only I5 LDC 3714C and LDC 3724C only Figure 3 3 Command Path Structure Syntax Summary Remote commands mus
74. OPERATION Command Syntax LDC 3700C Commonly Used Commands The LDC 3700C complete command set contains over 110 commands that allow you to operate the controller for a variety of applications Within the command set however is a smaller subset of commands that will meet most of your needs Table 3 3 LDC 3700C Commonly Used 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 Laser LAS CALMD 1 Used to set the CAL PD monitor responsivity constant jAS LDI 1 Used to set the LAS constant current source set point value AAS LDI NONE Used to return the constant current source measured value AAS LDV NONE Used to return the measured laser voltage value AS LIM 1I1 1 Used to set the LASER current source limit high range for 3714C low range for 3744C AS LIM 12 1 Used to set the LASER current source limit low range for 3724C 3744C AS LIM 13 1 Used to set the LASER current source limit high range for 3744C AS LIM I4 1 Used to set the LASER current source limit high range for 3744C AS LIM I5 1 Used to set the LASER current source limit low range for 3714C high range for 3724C AS LIM MDP 1 Used to set the constant optical power from monitor PD limit value A
75. R 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 terminals This condition causes the OUTPUT SHORTED light to come on LAS I 20 LAS OUT ON action sets the laser output current to 20 mA and then turns the output on LASer OUTput Notes Examples LDC 3700C Series DEVICE DEPENDENT FRONT PANEL The LASer OUTput query returns the status of the laser output switch Although the status of the switch is on the output may not have reached the set point value 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 Lightwave 04_09 COMMAND REFERENCE Command Reference LASer RANge Parameters Notes Examples DEVICE DEPENDENT FRONT PANEL The LASer RANge command selects the laser s drive current output range An nrf value which represents the laser current output range For LDC 3714C 5 50 mA and 1 100 mA range For LDC 3724C 2 200 mA and 5 500 mA range For LDC 3744C 1 2000 mA and 3 4000 mA 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 is
76. S LIM H response 40 means the laser current limit is 40 mA Laser LIM I1 response 500 means the laser current limit is 500 mA LDC 3744C only LASer LIMit I2 JOMMON DEVICE DEPENDENT FRONT PANEL The LASer LIMit 12 command sets the LASER current limit value for the 200 mA range on the LDC 3724C and the 2000 mA range on the LDC 3744C Not applicable for LDC 3714C Parameters nrf value which represents the LASER limit current in mA Notes The current limit is in effect in all modes of operation of the laser output with respect to the output range low high 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 DEVICE DEPENDENT FRONT PANEL The LASer LIMit 12 query returns the value of the LASER current limit for the 200 mA range on the LDC 3724C or the 2000 mA range of the LDC 3744C Not applicable for LDC 3714C Notes The current limit is valid for all modes of Laser operation for the respective output range Examples LAS LIM I2 response 40 means the laser current limit is 40 mA Laser LIM I2 response 150 means the laser current limit is 150 04 09 LDC 3700C Series 91 COMMAND REFERENCE Command Reference LASer LIMit I3 Parameters Notes Examples DEVICE DEPENDENT FRONT PANEL The LASer LIMit 13 command sets the LASER current limit value for the 4
77. S LIM V 1 Used to set the LASER current source compliance voltage limit value LAS MDP 1 Used to set the constant optical power set point LAS MDP NONE Returns the actual monitor PD power value AAS 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 mode AAS MODE I LBW NONE Sets the mode to constant current low bandwidth mode 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 TE Controller EC CONS 1 3 Used to enter temperature sensor constants C1 C2 and C3 EC CONST NONE Used to read back the temperature sensor constant values EC GAIN 1 Used to set the TEC control loop gain parameter EC LIM ITE 1 Used to set the TEC constant current source limit value 54 LDC 3700C Series Lightwave REMOTE OPERATION Command Syntax Table 3 3 LDC 3700C Commonly Used Commands EC LIM THI 1 Used to set the TEC upper temperature limit value EC MODE T NONE Sets the instrument to constant temperature mode EC OU 1 Used to enable disable the TEC output EC OUT NONE Returns the TEC output status EC 1 Used to set the TEC temperature set point EC T NONE Returns the TEC measured
78. SER DISPLAY selection is enabled Examples Las Display MDp action enables the LASER display for photodiode power values Laser Disp MDP action enables the LASER display for photodiode power values LASer DISplay PPD C DEVICE DEPENDENT FRONT PANEL The LASer DISplay MPD query returns the status of the LASER DISPLAY P switch Notes In local operation the status of the Ppp switch is indicated by the enunciator next to the LASER display mW will be illuminated when the display is in Ppp mode Examples LAS DISp MDp response 0 means that the LASER DISPLAY P switch is not currently active laser photodiode monitor power is not displayed Las dis MDP response 1 means that the LASER DISPLAY Pp switch is currently active PD power may be displayed LASer DISplay PARAM DEVICE DEPENDENT FRONT PANEL The LASer DISplay PARAM command enables the LASer display to show the LASER parameter values Parameters None Notes 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 LASER display selection is enabled Each time the command is issued the next LASER parameter will be selected see Chapter 2 for more information Examples Laser Display Param action selects a LASER parameter and displays its value LAS DIS PARAM action sel
79. Series 99 COMMAND REFERENCE Command Reference LASer SET MDI Notes Examples DEVICE DEPENDENT FRONT PANEL The LASer SET MDI query returns the laser monitor PD current set point value when CALPD 0 in pA The monitor photodiode current is directly proportional to the laser optical output power Therefore the lpp set point may be used to control optical output of the laser las set mdi response 30 0 means the laser monitor PD current is set point is 30 pA for use in constant P mode with CALPD 0 LAS Set MDI response 100 0 means the laser monitor PD current is set point is 100 for use in constant P mode with CALMD 0 LASer SET MDP Notes Examples DEVICE DEPENDENT FRONT PANEL The LASer SET MDP query returns the laser monitor PD power set point value when CALMD CAL PD is not zero in mW This set point is used in constant MDP mode only LAS Set MDP response 10 0 means the laser monitor PD feedback set point is 10 0 mW CALPD gt 0 Laser Set MDP response 25 0 means the laser monitor PD feedback set point is 25 0 mW CALPD gt 0 LASer STEP Parameters Notes Examples 100 LDC 3700C Series DEVICE DEPENDENT The LASer STEP command is used to increment or decrement the selected laser control mode set point by the given amount when used with the LASer INC or LASer DEC command An integer value of the step amount in the range 1 to 9999 The step
80. Steinhart Hart equation constants or the two linear calibration constants for linear IC sensors With v1 9 and higher the range of values is 99 999 to 99 999 for all three constants previously was 9 999 to 49 999 However for a thermistor sensor these values are scaled by the appropriate exponential value for the Steinhart Hart equation Notes If less than three parameters need to be changed only the desired change needs to be specified along with the separating commas see examples When the LM335 or AD590 sensors are selected via the SENSOR SELECT switch only C1 and C2 are used Therefore only two parameters are required in those cases Examples Tec CONST 1 2 33 0 5 action sets C1 to 1 000 C2 to 2 330 and C3 to 0 500 TEC const 1 4 action sets C1 to 1 400 C2 and C3 unchanged TEC Const 4 5 0 3 action sets C2 to 4 500 C3 to 0 300 and C1 is unchanged Tec CONST 1 4 2 015 action sets C1 to 1 400 C2 to 2 015 for two point calibration of AD590 or LM335 sensors C3 is unchanged but not used 04 09 LDC 3700C Series 111 COMMAND REFERENCE Command Reference TEC CONST Notes Examples DEVICE DEPENDENT FRONT PANEL The TEC CONST query returns the value of the TEC s Steinhart Hart constants or the linear sensor conversion constants The response is always in the form C1 C2 C3 When the LM335 or AD590 sensors are selected via the SENSOR SELECT switch only C1 and C2 are used Therefore C3 values
81. TEG Dis T response 0 means that the TEC DIS T switch is not enabled TEC load temperature is not displayed Tec dis T response 1 means that the DIS T switch is enabled temperature may be displayed 04 09 LDC 3700C Series 7 115 COMMAND REFERENCE Command Reference TEC ENABle COND COMMON DEVICE DEPENDENT The TEC ENABle COND command sets the status condition enable register of the TEC operations These conditions are summarized in bit 1 of the status byte Parameters nrf value whose sum represents the enabled bits 1 TE Current Limit 256 N A 2 Voltage Limit Error 512 Output Out of Tolerance 4 N A 1024 Output On 8 High Temperature Limit 2048 Ready for Calibration Data 16 TEC Interlock Enable 4096 N A 32 Booster Enable 8192 N A 64 Sensor Open 16384 N A 128 TE Module Open 32768 N A Notes The enabled TEC conditions can be read by using the TEC ENABle COND query The TEC condition status can be monitored by the TEC COND query If any of the enabled TEC conditions are true bit 1 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 see PSC Chapter 3 Examples TEC ENAB COND 513 action enables the TEC status condition register so that the Output Out of Tolerance and TE Current Limit conditions will be reported in the status byte register T
82. The LASER conditions which 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 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 04_09 LDC 3700C Series 77 78 COMMAND REFERENCE Command Reference LASer DEC nrf value gt lt nrf value Parameters Notes Examples LASer DISplay nrf value Parameters Notes Examples LDC 3700C Series DEVICE DEPENDENT The LASer DEC command decrements the selected laser control mode set point by one or more steps Optional parameters allow multiple steps to be decremented and the time in milliseconds between decrements to be set respectively 0 1 or 2 The first optional parameter is the number of steps and the second optional parameter is the number of milliseconds between steps
83. The LDC 3700C Series Laser Diode Controllers are a combination current source temperature controller The current source provides a high stability output with a fully redundant current limit and multiple laser protection features The built in temperature controller can work with most temperature sensors and TE modules to deliver precise laser temperature control over a wide range of temperatures The LDC 3700C Series fast sophisticated USB or GPIB communications lets you automate your experiment Initial Inspection When you receive your LDC 3700C Controller verify that the following items were shipped with the instrument LDC 3700C Laser Diode Controller LDC 3700C Series Manual Power Cord e Shipping Kit II LX Lightwave LDC 3700CSeries 1 INTRODUCTION AND SPECIFICATIONS Installing the LDC 3700C Installing the LDC 3700C This section provides information about the necessary requirements to install the LDC 3700C and how to begin operating the instrument Grounding Requirements The LDC 3700C Laser Diode Controller comes with a three conductor AC power cable The power cable must be plugged into an approved three contact electrical outlet or used with a three contact to two contact adapter with the grounding wire connected to an electrical ground safety ground The LDC 3700C supplied power cable meets all applicable national safety standards AC Line Power Requirements You can operate the LDC 3700C Series Co
84. W 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 mode low bandwidth LASer MODE MDP COMMON DEVICE DEPENDENT FRONT PANEL The LASer MODE MDP command selects laser constant power mode Parameters None Notes This mode of laser operation requires the laser s monitor PD 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 Ppp if CALMD gt 0 in mW Examples LAS MODE MDP action sets the laser output mode of operation to constant optical power mode 04 09 LDC 3700C Series 97 98 COMMAND REFERENCE Command Reference LASer OUTput Parameters Notes Examples DEVICE DEPENDENT FRONT PANEL The LASer OUTput command turns the laser output on or off An nrf value 1 on 0 off There is a 2 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 set point slowly to protect the laser Therefore the time to turn the output on and reach the set point current varies from 2 to about 3 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 LASE
85. a coded representation of the sensor type thermistor sensor current where the response of 1 thermistor at 100 uA 2 thermistor at 10 nA 3 LM335 sensor 4 AD590 sensor 5 RTD Note the RTD switch position is no longer used However the instru ment will still report 5 if the SENSOR SELECT switch is in that position Notes The sensor code is displayed on the TEC display and bit 8 of the TEC event register is set whenever the back panel SENSOR SELECT switch position is changed The sensor selection must be made locally at the back panel SENSOR SELECT switch If the response is 0 the sensor type is undetermined and a hardware error must exist Examples TEC Sensor response 1 means the SENSOR SELECT switch is in the 100 pA thermistor posi tion Tec SEN response 3 means the LM335 sensor is selected by the back panel SENSOR SELECT switch TEC SET ITE DEVICE DEPENDENT FRONT PANEL The TEC SET ITE query returns the TEC constant TE current set point value Notes The TEC output is controlled to this set point value only when constant ITE mode is in effect Examples TEG SET ITE response 3 0 means the ITE set point is 3 000 amps Tec Set Ite response 4 0 means the ITE set point is 4 000 amps TEC SET R OMMON DEVICE DEPENDENT FRONT PANEL The TEC SET R query returns the TEC s constant thermistor resistance or linear sensor reference set point value Notes The TEC output is controlled to this set point value only
86. action the LASER current limit is set to 2600 mA Lightwave COMMAND REFERENCE Command Reference LASer LIMit I4 C DEVICE DEPENDENT FRONT PANEL The LASer LIMit 14 query returns the value of the LASER current limit for the 4000 mA range on the LDC 3744C Not applicable for LDC 3724C or LDC 3714C Notes The current limit is valid for all modes of Laser operation Examples LAS LIM IA response 400 means the laser current limit is 400 mA LDC 3744C only Laser LIM IA response 1500 means the laser current limit is 1500 mA LDC 3744C only LASer LIMit I5 OMMC DEVICE DEPENDENT FRONT PANEL The LASer LIMit I5 command sets the LASER current limit value for the 50 mA range on the LDC 3714C and the 500 mA range on the LDC 3724C Not applicable for LDC 3744C Parameters nrf value which represents the LASER limit current in mA Notes The current limit is in effect in all modes of operation of the laser output with respect to the current output range In local operation the limit current is entered by selecting LIM parameter pressing and holding in the PARAMETER SET switch adjusting the ADJUST knob until the desired value is displayed and then releasing the SET switch Examples LAS LIM I5 50 action the LASER current limit is set to 50 mA Laser Limit l5 160 action the LASER current limit is set to 160 mA LDC 3724C only LASer LIMit I5 SOMMON DEVICE DEPENDENT FRONT PANEL
87. al steps DEVICE DEPENDENT The LASer DISplay command enables or disables turns off the LASER display and LASER section s indicator LEDs SYNTAX DIAGRAM An lt nrf value gt where 1 on 0 off Turning the LASER display and LEDs off means that a message of all blank spaces is sent to the LASER display and all of the LASER section s indicator LEDs will be turned off 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 Lightwave COMMAND REFERENCE Command Reference LASer DISplay DEVICE DEPENDENT The LASer DISplay query returns the value shown on the LASER display Notes Returns the actual 6 character string from the output buffer to the LASER 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 I DEVICE DEPENDENT FRONT PANEL The LASer DISplay LDI command sets the laser display to show the constant current measurement Parameters None Notes The actual LASER I display is turned off automatically when another LASER DISPLAY selection is enabled Examples LAS DIS LDI action enables the LASER display for current values LASer DISplay LDI I DEVICE DEPENDENT FRONT PANEL The LASer DISplay LDI query
88. alibration value TEC V Notes Examples 04 09 DEVICE DEPENDENT FRONT PANEL The TEC V returns the most recent TEC voltage measurement The TEC voltage measurement may only be read remotely The TEC voltage measurement response indicates the actual voltage at the TEC output Even when the TEC output is off there is a voltage present This voltage is due to a small leakage current which flows across the high impedance TEC output circuit Tec V response 0 2 means the LDC 3700C Series Laser Diode Controller has a TEC voltage of 0 2 volts TEC v response 1 2 means the LDC 3700C Series Laser Diode Controller has a TEC voltage of 1 2 volts LDC 3700C Series 7 131 COMMAND REFERENCE Command Reference TERM Parameters Notes Examples DEVICE DEPENDENT The TERM command allows the programmer to change the default IEEE488 2 standard terminator to include the carriage return An nrf value 0 FALSE non zero TRUE An altered terminator will be in the form CR 2 NL END This technically takes the LDC 3700C Series Controller out of IEEE488 2 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 3700C Series Controller is powered off Term 1 temporarily sets lt CR gt lt NL gt lt END gt as the output terminator Term response 0 means that the NL
89. allows you to generate service requests from overlapped commands as previous oper ations complete This may be useful for ensuring that an operation is complete before starting a measurement 70 LDC 3700C Series Lightwave COMMAND REFERENCE Command Reference ESE Event Status Enable COMMON Action Requests the value in the standard event status enable register Response The value must be between 0 and 255 Logical OR 7 6 5 4131211101 Standard Event Status Enable Register Bit Reference 0 Operation Complete 4 Execution Error 1 N A 5 Command Error 2 Query Error 6 User Request 3 Device Dependent Error 7 Power On Notes Bit 5 of the status byte register is set if any enabled conditions are true Response is the sum of the enabled bits 04 09 LDC 3700C Series 71 COMMAND REFERENCE Command Reference ESR COMMON Standard Event Status Register Action Requests the value in the standard event status register Response The value must be between 0 and 255 Logical OR 7 16 5 4 3 2 1 0 Standard Event Status Enable Register Bit Reference 0 Operation Complete 4 Execution Error 1 N A 5 Command Error 2 Query Error 6 User Request 3 Device Dependent Error 7 Power On Notes Response is the sum of the enabled bits This command allows you to determine which type of error has occurred 72 7 LDC 37000C Series Lightwave COMMAND REFERENCE Command Re
90. and is included in the shipping kit USB Driver Installation Insert the companion CD into the PC This CD is included with the LDC 3700C Series Laser Diode Controller shipment The instrument driver installation should run automatically but if it does not the executable can be found at CD ROM Drive Setup exe Follow the instructions of the installer to complete the installation um LX Lightwave LDC 3700C Series 43 1 REMOTE OPERATION Basic GPIB Concepts Basic GPIB Concepts LDC 3700C Series GPIB General Purpose Interface Bus is the common name for ANSI IEEE Standard 488 2 1987 an industry standard for interconnecting test instruments in a system The information in this basic concepts discussion is normally not necessary to successfully operate the LDC 3700C through its GPIB interface because your computer s GPIB controller usually handles them for you However this is a useful perspective in understanding GPIB Data and Interface Messages GPIB devices communicate with each other by sending data and interface messages Data contains device specific information such as programming instructions measurement results and instrument status Each device has an address number and ignores all data traffic not addressed to it Depending on its content data is often called a device dependent message or a device dependent command Interface messages manage the bus with functions such as initializing the bus and addressing
91. ations Calibrating the Thermistor 1 04 09 Set the SENSOR SELECT switch back panel to the 100 pA position the TEC display code is 01 Using the multimeter measure and record the resistance of your metal film resistors ILX recommends a 4 point probe resistance measurement Connect the correct metal film resistor to the sensor input of the Temperature Controller 15 pin connector on the rear panel sensor and sensor terminals Enter the TEC sensor calibration mode by pushing the Communications LOCAL and TEC DISPLAY R switches at the same time The sensor code SENSOR SELECT switch position value displays for 2 seconds After this the TEC display indicates sensor resistance in kQ Press and hold in the PARAMETER SET switch and turn the ADJUST knob until the TEC display indicates the same resistance you recorded for the metal film resistor Release the PARAMETER SET switch to store the new value into non volatile memory After the PARAMETER SET switch is released the LDC 3700C Series Laser Diode Controller will return to its former state before calibration Switch the SENSOR SELECT switch back panel to the 10 position TEC display code 02 and repeat this procedure with the 100 kQ resistor as the load at the Sensor and Sensor terminals LDC 3700C Series 139 CALIBRATION AND TROUBLESHOOTING Calibration Overview AD590 Sensor Calibration This procedure is for calibrating the AD590
92. ay issue the TEC COND query and read back the response to ensure this set point is reached before continuing In this case the TEC will not set bit 9 of the TEC condition register until its TEC load temperature is within 0 2 C of 10 for a period of 5 seconds The LDC 3700C Series Laser Diode Controller defaults to a tolerance of 0 2 C for 5 seconds unless changed by the TEC TOLerance command In R mode the temperature and time parameters are both in effect as in T mode In ITE mode the temperature parameter is not used A fixed value of 10 mA is used instead of the temperature parameter and only the time window may be adjusted If the tolerance is set too tight it may never be achieved This is due to the calibration of the set point and measurement values Tol 0 5 10 action the LDC 3700C Series Laser Diode Controller s TEC controller will be in tolerance when the temperature is within 0 5 C for a period of 10 000 seconds TOLer 0 1 1 05 action the LDC 3700C Series Laser Diode Controller s TEC controller will be in tolerance when the temperature is within 0 1 C for a period of 1 050 seconds TEC MODE ITE TOLer 10 action the LDC 3700C Series Laser Diode Controller s TEC controller is set for ITE mode and will be in tolerance when the ITE current is within 10 mA for a period of 10 000 seconds Tec Mode R TOLer 0 1 2 5 action the LDC 3700C Series Laser Diode Controller s TEC controller will be in tolerance when the temp
93. calibration FUNCTION STATE GPIB COMMAND LASER MODE I constant current low LAS MODE ILBW bandwidth RANGE LDC 3714C 100 mA LAS RANGE 1 LDC 3724C 500 mA LAS RANGE 5 LDC 3744C 2000 mA LAS RANGE 1 LASER LIMIT set to FS full scale of range jAS LIM Ix Set POINT LDC 3714C 60 mA AS LDI 60 LDC 3724C 400 mA jAS LDI 400 LDC 3744C 400 mA jAS LDI 400 1 With the LASER output off connect a calibrated voltmeter in parallel with a resistor 100 2 Watt for the LDC 3714C 15 5 Watt for the LDC 3724C or LDC 3744C to the LASER output Laser Anode and Laser Cathode on the rear panel of the controller 2 The LASER output must be on in order to enter the LDV calibration mode Enter the LAS OUT ON command to turn the LASER output on 3 Enter the LAS CAL LDV command to place the Controller in its LASER Voltage Calibration mode 4 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 LDC 3700C Series Laser Diode Controller is ready to receive it The Controller will be ready to receive the voltage value when after a LAS CAL LDV query is sent the response from the Controller is 1 5 Once the actual voltage value is entered via the LAS LDV nrf value command the Controller will set the current to approximately one fourth 1 4 of the original value It will then expect the second calibration voltage point 6 Input t
94. ch 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 LDC 3700C Series Laser Diode Controller has been on for 2 minutes and 0 31 seconds since the last TIMER query was issued TIMER response 00 00 12 03 means the LDC 3700C Series Laser Diode Controller has been on for 12 03 seconds since the last TIMER query was issued TST COMMON Test m Action Performs internal self test then reports results Response 0 test completed with no errors Non zero test not completed or was completed with errors Example TST WAI COMMON Wait to Continue Action Note Example 04 09 Prevents the instrument from executing any further commands until OPC operation complete status is true This command can be used to make the instrument wait until an operation is complete before continuing Care should be taken to set the GPIB time out appropriately for use with the WAI command After this command or the Delay command is sent the 3700C may receive up to 20 more commands before the wait period is over If more than 20 commands are sent before the delay or wait period is over the additional commands will be ignored and an error E220 will be g
95. command Las CAL MDI action the LDC 3700C Series Laser Diode Controller enters the LASER photodiode current calibration mode LAS Cal MDI action the LDC 3700C Series Laser Diode Controller enters the LASER photodiode current calibration mode LASer CAL IPD Notes Examples LDC 3700C Series MDI DEVICE DEPENDENT FRONT PANEL The LASer CAL MDI query is used to determine that the LDC 3700C Series Laser Diode Controller is ready for a value to be entered during the calibration cycle of the LASer CAL MDI mode After this query is issued and a response of 1 is received the LDC 3700C Series Laser Diode Controller be ready for the user to enter a photodiode current value via the LASer MDI command see Chapter 6 LAS CAL MDI response 1 means the LDC 3700C Series Laser Diode Controller is ready for the user to enter a photodiode current value via the LASer MDI command Lightwave COMMAND REFERENCE Command Reference LASer COND Con DEVICE DEPENDENT The LASer COND query returns the value of the status condition register of the LASER operations where the response is the sum of the following 1 LASER Current Limit 256 Output is shorted 2 LASER Voltage Limit 512 Output is outside tolerance limit 4 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 N A 16384 N A 128 Open circuit 32768 N A Notes
96. d the LDC 3700C Controller may be configured for another unique set up You can recall the original set up for the first experiment any time using the RECALL function To enter the SAVE RECALL mode first exit both TEC and LASER modes both TEC and LAS indicators in the ADJUST section off Press the SELECT switch in the PARAMETER section The SAVE indicator LED becomes lit and the unit displays the SAVE bin on the TEC display If another bin number is desired press 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 LIM he f LIM Tu LIM I SELE CONST LIMP GAIN CALPD SAVE SET RECALL c3 To recall a previously saved instrument set up press the SELECT switch until the RECALL indicator led becomes lit The instrument will display a RECALL bin number on the TEC display If you desire to change the RECALL bin press the SET switch and rotate the ADJUST knob until the desired bin number is displayed Releasing the SET switch completes the RECALL operation The 04 09 LDC 3700C Series 37 OPERATIONS Functions and Features instrument is restarted and the front panel parameters are reconfigured to the new parameters saved under that bin number Using the Laser Compliance Vol
97. d 10 mA V and 200 mA V and 400 for the LDC 3744C MOD EXTERNAL 13 20 mA V 50 mA V LDC 3700C Series 39 40 LDC 3700C Series OPERATIONS Functions and Features Set the LDC 3700C in Constant Current High Bandwidth Mode by selecting lupw in the LASER MODE section of the front panel Do this by toggling the SELECT push button until the lugy indicator is illuminated Repeatedly pressing the LASER MODE SELECT switch cycles through the current I light power P or high bandwidth current lugy control modes LASER MODE cp SELECT ES Jew i OUTPUT Set the laser controller s current source range by selecting the 200 mA range indicated by the accompanying LED You will need to press the select push button twice to change the range It must be pressed twice quickly within less than 1 second to switch between modes and the LASER output must be off LASER MODE ON indicator unlit in order to change ranges PRESS TWICE The limit clamp function for DC output current applies to the modulated current as well protecting your laser in any mode To accomplish setting the current source limit use the SELECT push button in the PARAMETER LASER section of the front panel to select LIM I You will notice there are two LIM I selections one in blue text and the other in black text These limit selections correspond to the current source
98. ditions ILX recommends calibration at 23 1 0 When necessary however the LDC 3700C Series Laser Diode Controller can be calibrated at its intended use temperature if this is within the specified operating temperature range of 0 50 C Finally the LDC 3700C Series Laser Diode Controller should be allowed to warm up for atleast 1 hour before calibration Recommended Equipment Recommended test equipment for calibrating the LDC 3700C Series Laser Diode Controller is listed in Table 5 1 Equipment other than that shown in the table may be used if the specifications meet or exceed those listed Table 5 1 Recommended Test Equipment Description Mfg Model Specification DMM HP 3457A DC Amps 1 0 A 0 02 Resistance 10 W 0 02 96 0 1 mA or 0 1 mV resolution You must connect various loads and circuits to the outputs of each controller for the calibration procedure A schematic is shown in Figure 5 1 for the photodiode 136 LDC 3700C Series Lightwave CALIBRATION AND TROUBLESHOOTING Calibration Overview calibration circuit with the required components listed in Table 5 2 on page 138 Also the devices required for other calibration loads are listed in Table 5 2 Interlock 1 y Interlock 2 LD Cathode 5 LD Anode 9 PD Cathode 6 PD Anode 7 9 Pin D Sub R1 49 U1 TIL111 9 V Batt Ipd Current IPDCAL Figure 5 1 lpp Calibratio
99. e user may also monitor the temperature of the TEC load via a remote algorithm of his her own design TEC R 20 5 action sets the set point thermistor resistance to 20 5 kO or sets the AD590 current to 20 5 uA or sets the LM335 voltage to 20 5 mV TEC Mode R TEC R 10 action sets the set point thermistor resistance to 10 0 or the AD590 current to 10 0 uA or the LM335 voltage to 10 0 mV The TEC output sensor is controlled to that value if the output is on TEC R Notes Examples 04 09 DEVICE DEPENDENT FRONT PANEL The TEC R query returns the value of the TEC thermistor resistance or AD590 current or LM335 voltage TEC load temperature is derived from the thermistor resistance or linear sensor reference measurement This measurement is updated approximately once every 600 msec TEC R response 10 543 means the measured TEC thermistor resistance is 10 543 or the measured AD590 current is 10 543 uA or the measured LM335 voltage is 10 543 mV depending on the SENSOR SELECT switch position Tec R response 0 728 means the measured TEC thermistor resistance is 728 ohms or the measured AD590 current is 0 728 uA or the measured LM335 voltage is 0 728 mV depending on the SENSOR SELECT switch position LDC 3700C Series 127 COMMAND REFERENCE Command Reference TEC SENsor DEVICE DEPENDENT The TEC SENsor query is used to read back the SENSOR SELECT switch position value This value is
100. e and don t tie up the GPIB during execution The delay time is approximate with an error of about 1096 Care should be taken to set the GPIB time out appropriately for use with the Delay command After this command or the WAI command is sent the 3700C Series Controller may receive up to 20 more commands before the delay period is over If more 04 09 LDC 3700C Series 69 COMMAND REFERENCE Command Reference than 20 commands are sent before the delay or wait period is over the additional commands will be ignored and an error E220 will be generated 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 Tec T 22 Delay 2000 Tec T actions The TEC is set to 22 0 C then the LDC 3700C Series Laser Diode Controller waits for about 2 0 seconds before returning the measured temperature ESE nrf value COMMON Event Status Enable Action Enables bits in the standard event status enable register Response The value must be between 0 and 255 7 6 5 4 3 2 1 O Standard Event Status Register Logical OR E 7 16 5 4 3 2 1 0 Standard Event Status Enable Register Bit Reference 0 Operation Complete 4 Execution Error 1 N A 5 Command Error 2 Query Error 6 User Request 3 Device Dependent Error 7 Power On Notes Bit 5 of the status byte register is set if any enabled conditions are true Setting bit O
101. e front panel to select LIM I either range and then press and hold the PARAMETER SET push button Then press the LASER DISPLAY V push button The LASER display will then indicate the LASER voltage limit setting While holding the PARAMETER SET push button adjust the voltage limit using the adjust knob LASER DISPLAY In the LASER 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 drives the current source to the value set by the corresponding LASER MODE set point The Output switch has a toggling action Pressing the switch again disables the current source output When the LASER output is off an internal short is placed across the LASER output and the Output Shorted indicator illuminates The default condition for the current source output is off when the instrument is first powered up LASER MODE EI SELECT uew ew C OUTPUT LDC 3700C Series 23 OPERATIONS Operating from the Front Panel Automatic Shutoff Conditions for Laser Output The following conditions automatically cause the instrument to disable the current source output from the instrument LASER High Power Limit LASER Interlock Key Lock turned off LASER Open Circuit or Voltage Limit TEC High Temperature L
102. e instrument and devices will occur 04 09 LDC 3700C Series 19 20 OPERATIONS Operating from the Front Panel Operating from the Front Panel This section describes fundamentals of operation for your LDC 3700C Series Controller Laser Current Source in two operating modes Constant Current 1 and Constant Power P The Laser Controller Display The LASER display is used to show LASER control parameters such as laser drive current mA laser current limit mA laser forward voltage V monitor photodiode current and laser optical power mW in both set point and measurement modes It will also display error codes which relate to LASER operation Error indicators underneath the display indicate control errors and are explained in the section titled LASER ERROR INDICATORS All laser control parameters are displayed on this portion of the controller s display section with the appropriate enunciator illuminated J J750 n 3 CG 5 INTERLOCK C3 VOLTAGE C3 CURRENT LIMIT OPEN CIRCUIT C2 OUTPUT SHORTED POWER LIMIT Operating a Laser in Constant Current I Mode Suppose you have an LDC 3724C Laser Diode Controller and you want to run the instrument in Constant Current low bandwidth mode with a set point of 150 mA and a current limit of 175 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 ma
103. e ready to adjust the set point operating temperature of the controller to 35 The LDC 3700C Series Temperature Controller will monitor actual temperature and adjust TE current to maintain the thermal load at the set point temperature To adjust the Temperature Set Point to 35 set the instrument to TEC mode by pressing the TEC push button in the ADJUST section This instrument mode will be indicated by the TEC LED Turn the adjust knob clockwise to increase the set point as indicated on the TEC display or counterclockwise to decrease the set point When the adjust knob is turned the controller automatically changes to set point mode indicated by the display enunciator flashing Before adjusting the set point check the TEC display for proper display mode The display mode determines which set point is being adjusted Adjust the set point temperature to 35 Three seconds after the set point is adjusted to the new value the instrument will return to measurement mode Pressing the SET switch in the TEC display switch section will also change the controller to set point mode and display the set point corresponding to the display mode ADJUST Once the sensors temperature control loop parameters and set points are established the output of the temperature controller can be enabled With the output enabled as indicated by the ON LED the temperature controller will drive current to the TE modules to cool or hea
104. easurement Parameters None Notes The actual TEC ITE display is turned off automatically when another TEC display selection is enabled Examples Tec Display lte action enables the TEC display for measured current values TEC DIS ITE action enables the TEC display for measured current values TEC DISplay ITE C DEVICE DEPENDENT FRONT PANEL The TEC DISplay ITE query returns the status of the TEC DISPLAY ITE switch Notes The response will be the status of the TEC DIS ITE switch 1 on 0 off Examples TEC DIS ITE response 0 means that the TEC DIS ITE switch is not enabled TEC output current is not displayed Tec DISp lte response 1 means that the TEC DIS ITE switch is enabled TEC current may be displayed TEC DISplay PARAM OMMON DEVICE DEPENDENT FRONT PANEL The TEC DISplay PARAM command enables the TEC display to show the parameter values Parameters None Notes This command has the same effect as pressing the PARAMETER SELECT switch while in TEC mode The selected parameter will be displayed for three seconds The actual TEC PARAM display is turned off automatically when a TEC display selection is enabled Each time the command is issued the next TEC parameter will be selected see Section 2 9 Examples Tec Display Param action selects a TEC parameter and displays its value TEC DIS PARAM action selects a TEC parameter and displays its value 04 09 LDC 3700C Series 113 CO
105. ec Enable Cond HODFB action enables the TEC status condition register so that any and all of the above conditions will be reported in the status byte register 1167 LDC 3700C Series Lightwave COMMAND REFERENCE Command Reference TEC ENABle COND COMMON DEVICE DEPENDENT FRONT PANEL The TEC ENABle COND query returns the value of the status condition enable register of the TEC operations 1 TE Current Limit 256 N A 2 Voltage Limit Error 512 Output Out of Tolerance 4 N A 1024 Output On 8 High Temperature Limit 2048 Ready for Calibration Data 16 TEC Interlock Enable 4096 N A 32 Booster Enable 8192 N A 64 Sensor Open 16384 N A 128 TE Module Open 32768 N A Notes The enabled TEC conditions can be set by using the TEC ENABle COND command The enabled TEC condition status can be monitored by the TEC COND query Examples TEC ENAB COND response 129 means that the TE Module Open and TE Current Limit conditions may be reported in the status byte register Radix Hex TEC Enable Cond response HOEFB means that any and all of the above conditions will be reported in the status byte register 04 09 LDC 3700C Series 7 117 COMMAND REFERENCE Command Reference TEC ENABle EVEnt COMMON DEVICE DEPENDENT FRONT PANE The TEC ENABle EVEnt command sets the status event enable register of the TEC operations These events are summarized in bit 0 of the status byte register Parameters
106. ects a LASER parameter and displays a its value 04 09 LDC 3700C Series 81 82 COMMAND REFERENCE Command Reference LASer DISplay SET COMMON DEVICE DEPENDENT FRONT PANEL The LASer DISplay SET command sets the laser display to show the set point of the selected LASER DISPLAY mode Parameters None Notes Using this command has the same effect as physically holding the LASER DISPLAY SET switch down in Examples Las Dis Set action enables the LASER display for the set point of the selected mode LDI MDI 1 or MDP Ppp LAS Dis Set action enables the LASER display for the set point of the selected display mode LASer DISplay SET DEVICE DEPENDENT FRONT PANEL The LASer DISplay SET query returns the status of the LASER DISPLAY SET switch Notes Examples LDC 3700C Series The set point display will not time out when REMOTE operation is used It will be continuously displayed LAS DISPLAY SET response 0 means the measured value is enabled for the LASER display Las Dis Set response 1 means the set point value is enabled for the LASER display Lightwave COMMAND REFERENCE Command Reference LASer ENABle COND nrf value COMMON DEVICE DEPENDENT ERON DANE 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 Parameters nrf value w
107. ed mode 1147 LDC 3700C Series ITE R or T TEC Dis Set action enables the TEC display for the set point of the selected mode ITE R or T Lightwave COMMAND REFERENCE Command Reference TEC DISplay SET Cc DEVICE DEPENDENT FRONT PANEL The TEC DISplay SET query returns the status of the TEC display set point switch Notes The set point display will not time out when remote operation is used It will be continuously displayed In local operation the status of the TEC DISPLAY SET switch is determined by visually inspecting the LED indicator on the switch lit ON Examples TEC DISPL SET response 0 means the set point value is disabled for the TEC display Tec Dis Set response 1 means the set point value is enabled for the TEC display TEC DISplay T COMMON DEVICE DEPENDENT FRONT PANEL The TEC DISplay T command enables the TEC display to show the TEC load temperature measurement Parameters None Notes The actual TEC T display is turned off automatically when another TEC display selection is enabled Examples Tec Dis T action enables the TEC display for the TEC load s measured temperature TEC DIS T action enables the TEC display for the TEC load s measured temperature TEC DISplay T DEVICE DEPENDENT FRONT PANEL The TEC DISplay T query returns the status of the TEC DISPLAY T switch Notes The response will be the status of the TEC DIS T switch 1 on 0 off Examples
108. enerated WAI Wait until OPC status is true LDC 3700C Series 133 COMMAND REFERENCE Command Reference 134 LDC 3700C Series Lightwave CHAPTER 5 CALIBRATION AND TROUBLES a E El a El mH El B Li HOOTING El E This chapter describes calibration of your LDC 3700C Series Laser Diode Controller Descriptions of the required test instruments calibration conditions and the detailed procedures for calibration of the instrument s Temperature Controller and the 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 It should be noted that while this section references using GPIB remote calibration can also be accomplished with USB ILX Lightwave Corporation provides in house and on site calibration services for ILX instruments Most ILX instruments require yearly calibration to ensure performance to published specifications ILX factory calibrations employ NIST traceable measurement instrumentation and our calibration engineers and technicians use automated test equipment to accurately and efficiently capture and record calibration data An original certificate of calibration authenticity is provided with all instrument calibrations and a detailed report showing any
109. equests Examples Las Tol response 0 2 5 0 means the LDC 3700C Series Laser Diode Controller 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 LDC 3700C Series Laser Diode Controller has a LASER current tolerance setting of 1 0 mA with a time window of 20 000 seconds MESsage DEVICE DEPENDENT The MESsage command allows the user to enter an ASCII string of up to 16 non zero characters This command may be useful for storing messages which relate to a test or configuration Parameters 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 mes sage 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 mem ory Mes Test 3 action The string Test 3 will be stored in non volatile memory MESsage DEVICE DEPENDENT 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 Notes The response data will be a 16 byte long string If there is no previously stored message the response will be
110. erature is within 0 1 for a period of 2 500 seconds Lightwave COMMAND REFERENCE Command Reference TEC TOLerance Notes Examples DEVICE DEPENDENT The TEC TOLerance query allows the programmer to determine how the TEC temperature tolerance is set The tolerance of the LDC 3700C Series Laser Diode Controller temperature controller may be used to delay programming after an TEC OUTput 1 command is issued or the set point is changed The TEC tolerance specification is also used in the TEC status event and condition registers and so entering or exiting TEC temperature tolerance may be used to generate service requests Tec Tol response 0 2 5 means the LDC 3700C Series Laser Diode Controller has a TEC tol erance setting of 0 2 C with a time window of 5 000 seconds TEC TOL response 1 0 20 means the LDC 3700C Series Laser Diode Controller has a TEC tolerance setting of 1 0 C with a time window of 20 000 seconds TEC V Parameters Notes Examples DEVICE DEPENDENT FRONT PANEL The TEC V command sets the TEC voltage value for calibration mode An nrf value which represents a TEC voltage calibration value If the user attempts to use this command when not in TEC voltage calibration an error E 419 will be generated TEC V 5 4 action the TEC voltage calibration accepts 5 4 volts as a calibration value Tec v 3 9 action the TEC voltage calibration accepts 3 9 volts as a c
111. ference ERRors DEVICE DEPENDENT The ERRors query returns a list of command and device errors which have occurred since the last query These errors are notated by a number which corresponds to the type of error which occurred See Chapter 3 for information regarding error handling 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 201 407 means that the PROGRAM DATA parameter value out of range error and the High Temperature Limit error were reported since the last query IDN COMMON Action Requests the instrument to identify itself Response Returns a comma delimited standard format ASCII identification string from information stored in the instrument during manufacture LASer CAL MD nrf value PD nrf value DEVICE DEPENDENT FRONT PANEL The LASer CALMD command sets the laser s photodiode feedback responsivity the CAL PD parameter Parameters nrf value in microamps milliwatt The range is 0 to 1000 Notes If the parameter is set to 0 the LDC 3700C Series Laser Diode Controller will operate in a constant lpp mode when Constant P mode is selected The parameter
112. g the error queue via GPIB clears the error queue Table 5 4 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 400 to E 499 TEC Control Errors E 500 to E 599 LASER Control Errors Note Errors codes not listed are reserved for future design use Table 5 5 Error Messages Error Code Explanation E 001 Memory allocation failure E 103 DEFINITE LENGTH ARBITRARY BLOCK PROGRAM DATA length too long E 104 NON DECIMAL NUMERIC PROGRAM type not defined E 105 DECIMAL PROGRAM DATA gt exponent not valid E 106 DECIMAL PROGRAM DATA gt digit expected E 123 Generic error code for command not found E 124 lt 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 will not convert to valid type E 203 Security violation command is not available without clearance E 205 PROGRAM is not a Boolean value or word E 207 PROGRAM will not convert to an unsigned 16 bit value 04 09 LDC 3700C Series 157 CALIBRATION AND TROUBLESHOOTING Troubleshooting Table 5 5 Error Messages Error Code Explanation
113. h remote communications the terminator string can sometimes be the cause Refer also to your GPIB interface controller manual Command Separators You can put more than one command on the same line same command string if you separate them with a semicolon The semicolon can be preceded by one or more spaces Examples EC DIS 1 tec set t EC MODE t TEC T 25 TEC Const 1 2 3 5 TEC OUT 141 Parameters Some commands require a parameter The parameter must be separated from the command by at least one space The syntax symbol lt nrf value refers to the flexible numeric representation defined by the GPIB standard It means that you can represent numbers in integer or floating point form or in engineering scientific notation The IEEE 488 2 standard uses the names NR1 NR2 and NR3 respectively to denote integer floating point and scientific notation For example the number twenty may be represented by any of the following ASCII strings Integer 20 20 NR1 Floating point 20 0 20 0 NR2 Scientific notation 2 0E 1 2 0E 1 NR3 2 0e 1 2 0e 1 For more information on these definitions refer to the IEEE 488 2 standard LDC 3700C Series 49 REMOTE OPERATION Command Syntax There are no default values for omitted parameters If a command is expecting a parameter and none is entered an error is generated For further clarity in programming the Boolea
114. he LDC 3700C Series Laser Diode Controller is ready the SET switch will become enabled and the user should enter the true measured value This procedure is outlined in Chapter 6 The TEC CAL SENsor query may be used to determine if the LDC 3700C Series Laser Diode Controller is ready for the user to enter a value Examples Tec CAL Sen action the LDC 3700C Series Laser Diode Controller enters calibration mode for the sensor which is selected by the back panel switch Tec Cal Sensor action the LDC 3700C Series Laser Diode Controller enters calibration mode for the sensor which is selected by the back panel switch TEC CAL SENsor DEVICE DEPENDENT FRONT PANEL The TEC CAL SENsor query is used to determine that the LDC 3700C Series Laser Diode Controller is ready for a value to be entered during the calibration cycle of the TEC CAL SENsor mode Notes This query can be used to poll the LDC 3700C Series Laser Diode Controller after the TEC CAL SEN command to determine if it is waiting for a value If the response is 1 the LDC 3700C Series Laser Diode Controller is ready to receive a calibration value via the TEC R command Chapter 6 A query of the TEC condition status register bit 11 has the same results Examples Tec CAL SEN response 1 means the LDC 3700C Series Laser Diode Controller is ready for the user to enter a resistance value via the TEC R command Tec Cal Sensor response 0 means the LDC 3700C Series Laser
115. he second actual measured LASER forward voltage as an nrf value 7 the second actual voltage value is entered via the LAS LDV command the Controller will store the new calibration constants 1547 LDC 3700C Series Lightwave CALIBRATION AND TROUBLESHOOTING Troubleshooting Troubleshooting This section is a guide to troubleshooting the LDC 3700C Series Controllers 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 which apply If you encounter problems which are beyond the scope of this guide contact your ILX Lightwave customer service representative Table 5 3 Symptoms and Actions Symptom Corrective Actions General LDC 3700C Series unit will not power up Check AC Power line voltage and power cord connection Power on but display is frozen switches This may occur if the instrument loses power AC do not operate line briefly Turn the power switch off and on again to restart Laser Contoller 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 through a switch If OPEN CIRCUIT indicator is lit check the load connections and then try again Check the OUTPUT ON switch the correspondi
116. hose 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 Reagy for Calibration Data State 16 Interlock Disabled 4096 N A 32 N A 8192 N A 64 N A 16384 N A 128 Open Circuit 32768 N A 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 IEEE488 2 specification Examples LAS ENAB COND 129 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 04 09 LDC 3700C Series 83 COMMAND REFERENCE Command Reference LASer ENABle COND COMMON DEVICE DEPENDENT FRONT PANEL The LASer ENABle COND query returns the value of the status condition enable register of the LASER operations The response
117. imit Condition Operating a Laser in Constant Power Mode P Suppose you want to operate a 3 mW laser in constant power at 1 mW The 3700C Series Controller allows you to operate the instrument current source driver in a Constant Power mode In this mode the controller drives current to the laser to reach a set power value in mW The control loop feedback parameter is photodiode current which the controller converts to optical power via a user defined photodiode responsivity number If laser power changes due to internal or environmental conditions the controller will increase decrease the current to the laser to maintain the power set point The following paragraphs detail the instrument configuration in Constant Power Mode To set the LDC 3700C in Constant Power mode select P in the LASER MODE section of the front panel by toggling the SELECT push button Repeatedly pressing the LASER MODE SELECT switch cycles through the current I light power P or high bandwidth current control modes The LED indicator shows the selected mode LASER MODE LJ SELECT CL uew sw OUTPUT Entering Photodiode Responsivity values The photodiode responsivity CAL PD is used to convert between photodiode current and optical power of the laser diode To enter the CAL PD parameter select CAL PD with the SELECT push button by toggling down past LIM P The indicator becomes lit when
118. ing material Shipping damage is not covered by this warranty 5 Secure the packing box with fiber reinforced strapping tape or metal bands 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 whichever 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 factory 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 7 LDC 3700C Series Lightwave 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 Tras 800 459 9459 or 406 586 1244 EEE E EEE EEE
119. inor injury or damage to the product Specifically A CAUTION Caution indicates a potentially hazardous situation which can result in minor or moderate injury or damage to the product or equipment warnine Warning indicates a potentially dangerous situation which can result in serious injury or death Pi 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 Lightwave LDC 3700C Series ix TJ 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 specification
120. ircuits for constant lp and constant 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 LDC 3700C Series Laser Diode Controller then automatically calibrates the LASER feedback circuits Configure the Controller in the following manner for the Laser Controller calibration FUNCTION STATE GPIB COMMAND PD BIAS VOLTAGE POT gt 3 5V LASER MODE P constant power AS MODE MDP CAL PD set equal to zero LAS CALMD LASER LIMIT 90 of FS full scale of range LAS LIM Ix lpp Set POINT 4000 pA LAS MDI 1 With the LASER output off connect a calibrated ammeter to the PD Anode output of the 04 09 Laser Controller output connector 9 pin on rear panel and connect the circuit of Figure 5 1 on page 137 to the LASER and PD outputs with the correct load resistor for the controller model you are calibrating See Table 5 2 on page 138 Enter the LAS OUT ON command to turn the LASER output Verify proper operation i e the lpp output should be close to the set point read it via the LAS MDI query 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 place the Controller in its LASER Current Calibration mode The controller will increase the laser current output until the current at the PD monitor Ipp inputs equals the targeted se
121. 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 N A 16384 N A 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 84 LDC 3700C Series Lightwave COMMAND REFERENCE Command Reference LASer ENABle EVEnt nrf value Con DEVICE DEPENDENT 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 Parameters nrf value whose sum represents the bits which are enabled 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 New Measurements Taken 16 Interlock Changed S
122. l 04 09 LDC 3700C Series 61 REMOTE OPERATION Command Syntax 62 7 LDC 3700C Series Lightwave CHAPTER COMMAND REFERENCE 5 B El a El mH Li El B a E El This chapter is a guide to all of the device dependent commands for the LDC 3700C Series Laser Diode Controller This chapter is divided into two parts The first part contains an overview of the remote commands used by the LDC 3700C Series Laser Diode Controller The second part contains all of the LDC 3700C Series Laser Diode Controller commands in alphabetical order The commands which 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 IU LX Lightwave LDC 3700C Series 63 T 4 COMMAND REFERENCE CHAPTER t Remote Command Reference Summary Remote Command Reference Summary This section contains all of the commands for the LDC 3700C Series Laser Diode Controller listed in alphabetical order Sub sections for each path are presented listing the commands which are legal for that path See Figure 3 3 on page 51 for command path tree structure Table 4 1 Remote Command Summary Reference List Name Parameters Function CAL Used for the A D calibration procedure CLS Resets the Standard Event Register Status Byte and Error Queue to zero
123. laser cathode and anode photodiode cathode and anode chassis ground and interlock The pinout diagram for this connector is shown in Figure 2 2 Make sure the laser current and voltage measurement connections are correct connect pin 4 Cathode Voltage Sense and pin 5 Laser Cathode to the laser diode cathode and connect pin 8 Anode Voltage Sense and pin 9 Laser Anode to the laser diode anode 1 2 Interlock 6 PD Cathode xj 5 3 Chassis Ground 7 PD Anode 4 Cathode Voltage Sense O 8 Anode Voltage Sense 5 Laser Cathode 9 Laser Anode csconn 2 Figure 2 2 Back Panel LD Connector Interlock Connections In order for the laser output to be enabled a short 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 illuminates on the front panel and the laser output is disabled A CAUTION The interlock terminals on the LASER connector pins 1 and 2 must be kept isolated from all other connections including earth ground 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 LDC 3700C Series Laser Diode Contr
124. late 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 LASER display indicates the calculated actual current 6 Release the PARAMETER SET switch After the PARAMETER SET switch is released the Controller will drive the LASER current output to about 25 of the first calibration set point 7 Calculate the measured current again through the load resistor 8 Press and hold in the PARAMETER SET switch and turn the ADJUST knob until the LASER display indicates the actual current as calculated in step 7 9 Release the PARAMETER SET switch to accept the second calibration point After the PARAMETER SET switch is released the Controller will calculate the calibration constants store them to nonvolatile memory In low bandwidth calibration mode the LDC 3700C Series Laser Diode Controller will also perform current limit calibrations for I Constant Current and P Constant Power modes indicated by the CURRENT LIMIT LED flashing 10 Change the Laser Mode to lugw high bandwidth constant current mode Repeat the calibration procedure as described above 04 09 LDC 3700C Series 143 CALIBRATION AND TROUBLESHOOTING Calibration Overview 1 Current Calibration The following procedure is for calibrating the LASER lpp photodiode monitor ammeter This procedure calibrates the feedback circuits for constant lpp and constant Ppp modes When these
125. les 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 04 09 LDC 3700C Series 87 D REFERENCE Command Reference 88 LASer ENABle OUTOFF DEVICE DEPENDENT The LASer ENABle OUTOFF query returns the value of the status outoff enable register of the LASER operations where the response is the sum of the following 1 LASER Current Limit 256 N A 2 LASER Voltage Limit 512 Output is Out of Tolerance 4 N A 1024 TEC Output Off 8 Power Limit With Output On 2048 TEC High Temperature Limit Condition 16 N A 4096 N A 32 N A 8192 N A 64 N A 16384 N A 128 N A 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 2049 means that TEC High Temperature Limit and Current Limit Conditions will cause the LASER output to be turned off Radix Hex Las Enab Eve response HEOB means that all of the above conditions will cause the LASER output to be turned off LASer EVEnt N DEVICE DEPENDENT The LASer EVEnt query returns the value of the status event register of the LASER operations
126. ller is ready for a value to be entered during the calibration cycle of the LASer CAL LDV mode Notes After this query is issued and a response of 1 is received the LDC 3700C Series Laser Diode Controller 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 LDC 3700C Series Laser Diode Controller is ready for the user to enter a voltage value via the LASer LDV command LASer Cal LdV response 0 means the LDC 3700C Series Laser Diode Controller is not yet ready for the user to enter a LASER voltage value 04 09 LDC 3700C Series 75 76 COMMAND REFERENCE Command Reference LASer CAL IPD Parameters Notes Examples MDI DEVICE DEPENDENT FRONT PANEL The LASer CAL MDI command is used to enter the LASER photodiode current calibration mode None After this command is issued the LDC 3700C Series Laser Diode Controller will automatically enter the LASER photodiode current calibration mode for the current LASER range When the LDC 3700C Series Laser Diode Controller is ready the user should enter the true measured value This procedure 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 LDC 3700C Series Laser Diode Controller is ready for the user to enter a value via the LASer MDI
127. lowing service request interrupts after power on Examples PSC 0 Disable automatic power on clearing of the enable registers PSC 1 Enable automatic power on clearing of the enable registers 04 09 LDC 3700C Series 103 104 COMMAND REFERENCE Command Reference PSC Power on Status Clear Action Response Example Requests the state of the power on status clear flag 0 The enable registers are saved through power OFF ON 1 The enable registers are cleared during power ON Registers affected Condition Status Enable Service Request Enable Event Status Enable Standard Event Status Enable See Chapter Three for more information on register structure PSC Request state of power on status clear flag PUD Action Notes Stores data unique to the instrument such as calibration date and serial number This data is protected from change by the SECURE lt gt command and is usually entered by the factory The arbitrary block program data is exactly 25 bytes long PUD Action LDC 3700C Series COMMON F DEPEN DEvic Requests the factory stored identification string Lightwave COMMAND REFERENCE Command Reference RADix Parameters Notes Examples DEVICE DEPENDENT 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 Character pr
128. ltage limit setting The voltage limit is valid for all modes of Laser operation In local operation the voltage limit is seen by selecting the LIM parameter pressing and holding in the PARAMETER SET switch and then pressing the LAS DISPLAY V Switch Examples LAS LIM V response 4 5 means the laser compliance voltage limit is 4 5 volts Laser LIM V response 10 0 means the laser compliance voltage limit is set to 10 0 volts LASer MDI DEVICE DEPENDENT FRONT PANEL The LASer MDI command sets the value of the optical power set point in pA if the CALMD CAL PD responsivity is 0 Parameters nrf value which represents the photodiode feedback current in 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 set point 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 pA LASer MDI gt O DEVICE DEPENDENT FRONT PANEL The LASer MDI query returns the value of the laser photodetector current measurement in uA Notes The response is in uA The response is valid even when the unit is not in constant P mode This measurement is updated approxima
129. lue COMMON Save s Action Saves the current setup configuration in memory Value range 1 through 10 Notes Configuration 0 is reserved for a factory set default configuration See RCL It is normally not necessary to save the current setup for next power ON The current setup is automatically stored for recall at next power ON unless you use PSC not to do so Example SAV 2 Save the current setup configuration as 2 106 LDC 3700C Series Lightwave COMMAND REFERENCE Command Reference SRE nrf value COMMON DEVICE DEPEN Service Request Enable E Action Enables bits in the service request enable register Notes Response is the sum of the enabled bits Example SRE 136 Enable the service request enable register condition summary and error message bits 8 128 136 SRE CoMMON Service Request Enabled Action Requests the value in the service request enable register Notes Response is the sum of the enabled bits See Chapter Three for more information about register structure Example SRE Response 136 means the service request enable register condition summary and error message bits are enabled 8 128 136 STB COMMON Status Byte Action Requests the value in the status byte register Notes Response is the sum of the enabled bits See Chapter Three for more information about register structure Example STB Response 200 means the status byte condition and master status su
130. lue and time period value LAS TOL NONE Used to return the LASER set point 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 OPC Generates the OPERATION COMPLETE message in the Standard Event Status Register OPC Places an ASCII character 1 into the Output Queue PSC Used to avoid any undesirable service requests PSC Queries the power on status clear flag PUD Stores data unique to the instrument PUD Retrieves the contents of the PUD storage area 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 RCL 1 Recall a stored setup configuration RST Performs a device reset SAV 1 Save the current setup configuration SECURE 1 Used to gain access to protected data SRE Sets the Service Request Enable Register bits to allow generation of the user selectable service requests SRE Determines the current contents of the Service Request Enable Register STB Reads the Status Byte TEC CAL CONST TEC CAL ITE Factory use only Used to enter the TEC current source calibration mode LDC 3700C Series Lightwave 04_09 COMMAND REFERENCE m Remote Command Reference Summary Table 4 1 Remote Command Summary Reference List
131. mit until the actual temperature is within a few degrees of the set point To set the TE module current limit to 2 Amps press the PARAMETER SELECT switch until the LIM lyg indicator is lit Press and hold in the SET switch while turning the ADJUST knob until 2 000 A is displayed on the TEC display When the SET switch is released this new value will be stored in non volatile memory TEC mmm PARAMETER LASER LIMITE LIM I mi C3 LIM THI SELECT LIM I CONST GAIN CAL PD r3 II SAVE SET RECALL Cj The Temperature Controller temperature limit function LIM sets the maximum temperature the controller allows before generating an error condition and action During controller operation if this limit is reached the TEMP LIMIT error indicator will flash and the LASER and TEC output will be shut off to protect the laser Note The maximum temperature limit becomes the maximum set point temperature as well To set the controller temperature limit to 40 press the PARAMETER SELECT switch until the LIM indicator illuminates Press and hold in the SET switch and turn the ADJUST knob until the TEC display indicates 40 When the SET LDC 3700C Series 33 OPERATIONS Operating the TE Controller from the Front Panel switch is released the new value is stored in non volatile memory and becomes the maximum set point value Adjusting the Temperature Set Point Now you ar
132. mmary bits and error message bits are enabled 8 64 128 200 TEC CAL CONST COMMON DEVICE DEPENDENT The TEC CAL CONST query returns a stored calibration value It is intended for factory use only 04 09 LDC 3700C Series 107 COMMAND REFERENCE Command Reference TEC CAL ITE C DEVICE DEPENDENT FRONT PANEL The TEC CAL ITE command is used to enter the TEC s current set point measurement and limit calibration mode Parameters None Notes This is a service related command When this command is issued the front panel becomes disabled and the appropriate adjustments are made to the operating modes This mode should not be entered unless the user has the proper measurement equipment in place See Chapter 6 After this command is issued the LDC 3700C Series Laser Diode Controller will automatically change to ITE mode turn the TEC output on determine its zero current offset set the ITE limit to 4 0 amps and drive the output to 1 0 amps This procedure is outlined in Chapter 6 The TEC CAL ITE query or bit 11 of the TEC status condition register may be used to determine if the LDC 3700C Series Laser Diode Controller is ready for the user to enter a value Examples Tec CAL ITE action the LDC 3700C Series Laser Diode Controller enters calibration mode for current Tec Cal lte action the LDC 3700C Series Laser Diode Controller enters calibration mode for current TEC CAL ITE DEVICE DEPENDENT FR
133. mperature Then reduce the gain to the next lower value To set the gain press the PARAMETER SELECT switch until the GAIN indicator is lit The TEC display will show the value of the control loop GAIN To change the GAIN press and hold in the SET switch at the same time turn the ADJUST knob until the desired new value is on the TEC display then release the SET switch When the SET switch is released the new value will be stored in non volatile memory TEC PARAMETER III LASER C3 LIMITE LJ UMI C3 LIM THI UMI C3 CONST UMP GAIN CAL PD C3 I SAVE RECALL At this point the sensor type is selected the appropriate constants are entered and the temperature control loop gain is set Next the display will be configured to read in the correct units for operation in Constant Temperature mode The enunciators next to the TEC display will indicate the display mode corresponding to the switch pressed C will illuminate when the T push button is pressed The TEC DISPLAY section is used to select the displayed temperature T sensor value R or TE module current lre Press T for temperature and the display will indicate measured temperature in C When the R switch is pressed the display will show the measured thermistor resistance the measured LM335 voltage in mV not annunciated or the measured AD590 current in not annunciated 32 LDC 3700C Se
134. n 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 FALSE 0 SET 1 RESET 0 If multiple parameters are expected they should be separated with commas For example to set the Steinhart Hart constants on the LDC 3700C Series Laser Diode Controller C1 C2 and C3 the following command could be sent TEC CONST 1 111 2 004 0 456 If not all of the parameters need to be changed the other parameters may be omitted For example TEC CONST 1 111 0 456 A query has no space between the mnemonic and the question mark as in LAS LDI Command Tree Structure Many of the LDC 3700C remote commands require a compound structure This is done to distinguish between different commands of the same type and to designate the side of the LDC 3700C the command is intended TEC thermoelectric controller or LAS laser current source The first mnemonic opens a path to a set of commands relating to that path The second mnemonic then defines the actual command The compound command structure is similar to a directory path structure as found in DOS For example commands which deal with the LDC 3700C TEC have the path TEC as in the command to set the TEC display to measured resistance TEC DIS R 50 LDC 3700C Series Lightwave 04_09 REMOTE
135. n Circuit 04 09 LDC 3700C Series 7 137 138 Calibration Overview Table 5 2 Required Calibration Components CALIBRATION AND TROUBLESHOOTING LASER CURRENT SOURCE CALIBRATION Current Source Calibration all models 1Q 20W resistor low TCR Voltage Measurement Calibration LDC 3714C LDC 3724C LDC 3744C 100Q 2W resistor low TCR 250 resistor low TCR 250 resistor low TCR TEMPERATURE CONTROLLER CALIBRATION Current Source Calibration all models 1Q 20W resistor low TCR TEC Voltage Calibration all models 500 5W resistor low TCR Thermistor 10 setting 100 pA setting 100 resistor 196 1 4W 10 resistor 1 1 4W LM335 6 8 kQ resistor 1 1 4W AD590 16 8 resistor 1 1 4 W PHOTO DIODE MONITOR CALIBRATION See schematic in Figure 5 1 on page 137 PD cal circuit R1 490 resistor 196 1 4W R2 1000 resistor 196 1 4W R4 1 0 MO resistor 196 1 4W R3 LDC 3714C 20 196 1W LDC 3724C LDC 3744C 5 196 10 U1 TIL 111 opto isolator Battery 9 V Battery Connector 9 pin D sub Male LDC 3700C Series Lightwave CALIBRATION AND TROUBLESHOOTING Calibration Overview Local Calibration of the LDC 3700C Temperature Controller The following procedure is for calibrating the 100 WA and 10 uA thermistor current sources so that the thermistor resistance measurement for these ranges will meet the stated accuracy specific
136. n titled TEC ERROR INDICATORS All TEC control parameters are displayed on this portion of the controller s display section with the appropriate enunciator illuminated In the case of the temperature sensor constants the LASER display section displays which constant you are viewing or adjusting C1 C2 or C3 and the TEC display section displays the value TEC 770708 LI C 3 I TEMP LIMIT IG TECURRENT LIMIT L SENSOR OPEN TEMODULE OPEN Operating the Controller in Temperature Mode T Suppose you need to operate and temperature control a telecom laser with an internal TE module The maximum TE module operating current for this device is 4 Amps A typical operating mode would be to control the laser diode temperature to 35 C with the temperature sensor type being a 10 thermistor In this experiment the maximum operating temperature will be 40 To configure the LDC 3700C Controller you will need to select a sensor type and the sensor current range via the rear panel enter the correct thermistor constants select the Temperature Control mode set the control loop gain and set appropriate temperature and TE module current limits Setting up the Temperature Controller Set the LDC 3700C in Temperature Control mode by selecting T in the TEC MODE section of the front panel Do this by toggling the SELECT push button until the T indicator is illuminated Repeatedly pressing the SELECT switch cycles 04 09 LDC 3700C
137. nch wide rack Temperature Controlled Laser Diode Mount LDM 4407 Temperature Controlled Laser Diode Mount available with collimating LDM 4412 assembly DIL Laser Diode Mount LDM 4982 Butterfly Laser Diode Mount LDM 4984 High Power Laser Diode Mount LDM 4442 Current Source Interconnect Cable unterminated CC306S Current Source Interconnect Cable terminated CC305S TEC Interconnect Cable unterminated CC501S TEC Interconnect Cable terminated CC505S Calibrated 10 Thermistor TS 510 Uncalibrated 10 kQ Thermistor TS 520 Uncalibrated AD590LH IC Temperature Sensor TS 530 Uncalibrated LM335AH IC Temperature Sensor TS 540 RTD Temperature Sensor Converter TSC 599 Other Laser Diode Mounts and Thermistor models are available Please contact ILX Lightwave for information on additional options for your applications 04_09 LDC 3700C Series 11 INTRODUCTION AND SPECIFICATIONS General LDC 3700C Specifications 12 LDC 3700C Series Lightwave CHAPTER 2 OPERATIONS 5 B El a a El El mH E m El m E This chapter introduces you to the operation of the LDC 3700C Series Controllers It offers instructions for connecting your laser to the current source and temperature controller and describes powering up the instrument This chapter also contains step by step procedures that teach you how to operate your controller in Constant Current Mode Constant Power Mode and to operate the temperature controller in Consta
138. ng LED should be lit Output current at limit cannot be lowered If POWER mode is used check the monitor diode feedback connections Try reversing the polarity of the monitor photodiode Check also the photodiode bias adjustment on the rear panel If in I or lygw mode check the current set point and LIMIT setting Setting the output below the limit may require several turns of the adjust knob if the Set point 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 that 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 Unable to adjust output Check the ADJUST LASER indicator the indicator must be lit for any LASER adjustments to be made Check the I LIMIT parameter for the output range in use see that it is set above 0 mA Power Mode operation has high output Check back panel PD BIAS If set too low may act current but little or no power is measured as an open feedback loop If in doubt set the PD BIAS to mid range 2 5 V 04 09 LDC 3700C Series 155 Troubleshooting Table 5 3 Symptoms and Actions CALIBRATION AND TROUBLESHOOTING Symptom Corrective Actions Output exceeds Power Limit The Power Limit is not a hardware limit It only serves as a warning that the power measurement
139. nstrument will drive the current source to the value set by the corresponding LASER MODE set point When the LASER output is off an internal short is placed across the laser output This condition is indicated by the OUTPUT SHORTED indicator becoming lit To disable the output press the OUTPUT push button again LASER MODE SELECT OUTPUT lugw ON L Boosting the TE Controller For users who need more than 16 Watts of TE Controller power a booster current source may be required and the LDC 3700C Series Temperature Controller may be used as the control element This section describes the use of the LDC 3700C s Temperature Controller as a remote temperature controller Whenever a connection is present between the BOOSTER PRESENT pin 14 and DIGITAL GROUND pin 15 of the back panel TEC Input Output connector see Figure 2 5 the LDC 3700C s TEC OUTPUT will be disabled In this case a BOOST CONTROL signal voltage equal to 10 0 Volts will be available for controlling an independent current source This control voltage is available between the BOOST CONTROL pin 10 and AGND pin 9 1 2 TE Module 3 4 TE Module 5 TE Module Shield 6 Sensor Shield 7 Sensor 8 Sensor 9 Analog Ground 10 Control Signal 11 Voltage Limit 12 Current Limit 13 Temp Limit 14 Booster Present 18 Digital Ground Figure 2 5 Rear Panel TEC Connector 04 09 LDC 37
140. nt Temperature Mode ILX recommends that you review the contents of this chapter at a minimum before operating your new controller Applying Power to your LD Controller To turn on the LDC 3700C Controller rotate the key in the POWER section of the front panel from to I This action initiates the power on sequence If the LDC 3700C 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 line power fuse Note The instrument contains a laser current source that has remote interlock capability This allows you to connect the interlock circuit to an external switch for safety If the interlock is removed the laser current output is disabled Refer to the laser module manual for details about the interlock function The instrument is also equipped with a laser enable key switch This ensures that the laser current can be turned on only if the key is inserted and in the On position 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 displays in the LASER display section followed by the TEC sensor switch position displayed on the TEC display Then a self test is performed to ensure that the instrument s hardware and processor are communicating After this te
141. nt value LAS LDI NONE Used to return the constant current source measured value LAS INC 0 10r2 Used to increment the LASER set point 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 LAS LIM I1 1 Used to set the LASER current source limit low range for 3714C 3744C LAS LIM I1 NONE Used to return the LASER current source limit low range for 3714C 3744C LAS LIM I2 1 Used to set the LASER current source limit low range for 3724C LAS LIM I2 NONE Used to return the LASER current source limit low range for 3724C LAS LIM I3 1 Used to set the LASER current source limit high range for 3744C LAS LIM I3 NONE Used to return the LASER current source limit high range for 3744C LAS LIM 14 1 Used to set the LASER current source limit high range for 3744C LAS LIM 14 NONE Used to return the LASER current source limit high range for 3744C LAS LIM I5 1 Used to set the LASER current source limit high range for 3714C 3724C LAS LIM I5 NONE Used to return the LASER current source limit high range for 3714C 3724C LAS LIM MDP 1 Used to set the constant optical power from monitor PD limit value LAS LIM MDP NONE Used to return the optical power from monitor PD limit value LAS LIM V 1 Used to set the LASER compliance voltage limit value LAS LIM V NONE Used to return the LASER compliance voltage limit value L
142. ntroller is ready to receive it The Controller will be ready to receive the measured value when after a TEC CAL SEN query is sent the response from the Controller is 1 5 Once the TEC R value is sent the Controller will return to its former state before calibration The oPc query may be used after the TEC value is sent to determine when the calibration is completed LM335 Sensor Calibration The following procedure is for calibrating the LM335 sensor so that the measured temperature will be as accurate as possible This procedure is for remote operation through the GPIB Interface 1 Setthe SENSOR SELECT switch back panel to the LM335 position TEC display code is 03 2 Connect a precision 6 8 metal film resistor and the multimeter in parallel to the sensor input of the Temperature Controller 15 pin connector on the rear panel Configure the multimeter to measure voltage in mV 3 Enterthe TEC CAL SENsor command over the GPIB The TEC display will show the voltage in mV not annunciated 4 Input the actual voltage measured by the multimeter as an nrf value via the TEC R nrf value command If this value is to be measured and entered remotely via a GPIB controlled DMM for example the measured value of the voltage should not be entered until the Controller is ready to receive it The Controller will be ready to receive the voltage value when after a TEC CAL SEN query is sen
143. ntrollers from a single phase power source delivering nominal line voltages of 100 120 220 230 240 VAC all values RMS from 50 to 60 Hz The line power voltage can vary 10 Maximum power consumption is 360 VA Volt Amps The instrument s operational voltage is configured at the factory and cannot be changed However check to make sure the voltage printed on the back panel of the instrument matches the power line voltage in your area WARNING Before connecting the LDC 3700C Laser Diode Controller to a power source verify that the AC power source matches the setting of the LDC 3700C s voltage printed on the rear panel of the instrument To avoid electrical shock hazard connect the instrument to properly earth grounded electrical receptacles only Failure to observe this precaution can result in severe injury or death USB The USB connector is located on the back rear panel directly below the GPIB connector This USB connector is the square B style connector A standard USB A B cable is required to communicate with the instrument To communicate to the instrument using USB please install the Virtual Com Port Driver found on the accompanying CD or website prior to connecting the unit to the PC Please refer to Chapter 3 for more detailed instructions on operating the instrument through USB LDC 3700C Series Lightwave 04_09 INTRODUCTION AND SPECIFICATIONS Installing the LDC 3700C n GPIB Connector The IEEE
144. ny TEC adjustments to be made Check the MODE or DISPLAY indicators If they do not respond to a switch the unit may be in measurement calibration mode Cycle the power Switch to abort this mode Output goes off intermittently Check that 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 Check the TE module connections A high impedance on the TE load may cause the output to exceed the compliance voltage momentarily thus shutting the output off 156 LDC 3700C Series Lightwave CALIBRATION AND TROUBLESHOOTING Troubleshooting 2 Error Messages In the event of a hardware error condition error messages are displayed on the TEC or LASER displays In most cases the error message appears for three seconds In the case of multiple error messages the Controller will sequentially show each message for three seconds In addition to the hardware errors GPIB errors may be read via the ERR query Table 5 4 lists the numerical error ranges by function Table 5 5 contains all of the potential error messages Not all of these messages may appear on the front panel displays some refer to remote communications activities only In remote operation the errors can be read by issuing the ERR query When this is done all of the error messages which are resident in the error queue are returned up to 10 may be stored Readin
145. o set the TEC current to zero for the start of this procedure 3 Enterthe TEC CAL V command to place the Controller in its TEC Voltage Calibration mode The TEC display will indicate a current of about 0 12 Amps so that the TEC voltage will be about 6 00 volts 4 When the Controller is ready for the actual voltage value to be entered a remote query of TEC CAL V Will return a response of 1 Allow a few seconds for the TEC current to stabilize When the measured value display is stable and the Controller is ready to proceed enter the value by issuing the TEC V nrf value command where the actual TEC voltage on the DMM is the lt nrf value Once the actual TEC voltage value is entered via the TEC V nrf value command the new calibration value is stored into non volatile memory Note To ensure measurement stability of the actual TEC voltage value when the measurement is taken as a part of an automated test the DMM measurement should be polled in a loop When the measured value is consistent within one digit for 5 seconds for example the actual TEC voltage value could be considered stable If the oPC query is issued during TEC voltage calibration the time out period of the GPIB driver should be at least one minute to prevent the GPIB driver from timing out and hanging the system Refer to your GPIB driver instruction manual for information on setting the GPIB driver time out period 5 The controller
146. of 1 corresponds to the smallest display resolution for the mode For example a step of 1 means 0 1 mA 3744C or 0 01 mA 3724C or 0 002 mA 3714C 100 mA range or 0 001 mA 3714C 50 mA range 0 01 mW or 1 uA if CALPD 0 Las Mode i Las ldi 20 Las Step 100 Las Inc Las set ldi action sets the step to 1 0 mA 3724C so the Las set ldi query will return a value of 21 0 mA LAS STEP 1000 action sets the step size to 1000 could mean 10 0 mA 3724C 10 0 mW or 100 Lightwave COMMAND REFERENCE Command Reference LASer STEP DEVICE DEPENDENT 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 set point by the given amount when used with the LASer INC or LASer DEC command Examples Las Mode LDI Las Step response 1 means the step size is 0 1 mA 3744C since Const mode is in effect LAS MODE MDP LAS CALMD 1 LAS STEP response 10 means the step size is 0 1 mW since Const P mode is in effect LASer TOLerance DEVICE DEPENDENT 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 set point is changed Parameters Two nrf values the first represents the LASER current tolerance in mA with a range of 0 1 to 100 0 m
147. 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 LDC 3700C Series 105 COMMAND REFERENCE Command Reference RCL nrf value DEVICE DEPENDENT Recall Action Recalls a stored setup configuration from memory Value range 0 through 10 Notes Setup 0 has a factory set default configuration If you use GPIB or USB to recall setup 0 RCL 0 the LOCAL REMOTE mode is set to REMOTE If you recall setup 0 by the front panel the LOCAL REMOTE mode is set to LOCAL Same function as RECALL on the front panel Use SAV to store various setup configurations for convenient recall The current setup is automatically stored and recalled at next power ON unless you use PSC to tell the instrument not to do so Examples RCL 0 Recall the factory default setup RST COMMON Reset i Action Performs a device reset and the following Sets OCIS state Sets OQIS state Notes OCIS Operation complete Command Idle State This is the same state as after OPC no further operations to complete OQIS Operation complete Query Idle State This is the same state as after OPC further operations to complete These idle states allow the 8033 to complete its reset process no operations pending before con tinuing with other operations Example RST SAV nrf va
148. ogram data is expected as shown above 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 nrf value as shown in the Command Reference diagrams will be replaced by HEX BIN or OCT representation 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 O 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 rad hex ESR action the hexadecimal radix is selected response H80 means power on was detected RADix Notes Examples 04 09 DEVICE DEPENDENT DAN The RADix query allows the programmer to determine which radix type for status condition and event query response data is currently selected Decimal binary octal and hexadecimal are allowed DEC is the default type The LDC 3700C Series Laser Diode Controller 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
149. oller are electrically isolated from ground and each other So if a 4 pin 04_09 LDC 3700C Series 17 OPERATIONS Connecting to the Laser Controller connection is made no common connections no additional jumpers are required Figure 2 1 on page 16 shows the recommended connections and shielding for 3 pin lasers where the common connection is internal to the device 4 pin laser should be connected with the same shielding as shown in Figure 2 1 on page 16 but the common connection between the photodiode and the laser is optional Setting the PD bias The LDC 3700C Series Laser Diode Controller provides an adjustable reverse bias of 0 5 VDC for the photodiode To set the photodiode bias to 5 volts reverse bias turn the back panel PHOTODIODE BIAS ADJUST fully clockwise To set the photodiode bias to 0 volts reverse bias turn the back panel PHOTODIODE BIAS ADJUST fully counter clockwise Grounding Considerations The LASER outputs of the LDC 3700C Series Laser Diode Controller are isolated from chassis ground allowing either output terminal to be grounded at the user s option Figure 2 1 on page 16 shows the proper earth ground shielding for laser diode photodiode connections 18 7 LDC 3700C Series Lightwave OPERATIONS Connecting to the TE Controller Connecting to the TE Controller The 15 pin connector marked TE CONTROLLER on the rear panel of your Controller is used to make connections to the thermoelec
150. onse from the Controller is 1 5 Once the TEC R value is sent the Controller will return to its former state before calibration The oPC query may be used after the TEC R value is sent to determine when the calibration is completed 6 Switch the SENSOR SELECT switch back panel to the 10 pA position TEC display code is 02 and repeat this procedure with the 100 resistor as the load at the Sensor and Sensor terminals LDC 3700C Series 147 CALIBRATION AND TROUBLESHOOTING Calibration Overview AD590 Sensor Calibration The following procedure is for calibrating the AD590 sensor so that the temperature measurement will be as accurate as possible 1 Setthe SENSOR SELECT switch back panel to the AD590 position TEC display code is 04 2 Connect a precision 16 8 metal film resistor and multimeter in series at the sensor input of the Temperature Controller 15 pin connector on the rear panel Configure the multimeter to measure current in pA 3 Enterthe TEC CAL SENsor command over the GPIB The TEC display will show the current value not annunciated 4 Input the actual current measured by the external ammeter as an lt nrf value viathe TEC R nrf value 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 LDC 3700C Series Laser Diode Co
151. or unaddressing devices In addition some individual bus lines are designated for this purpose Talkers Listeners and Controllers Every GPIB system consists of one or more talkers and listeners and often at least one controller Talkers supply data Listeners accept data A system can consist of simply a talker and listener for example a meter connected to a datalogger or chart recorder Controllers designate talkers and listeners A controller is necessary when the active talkers or listeners must be changed When the controller is a computer it often also designates itself as a listener so it can collect data from designated talkers If there is more than one controller only one can be the Controller In Charge CIC Control can be passed from one controller to another In a multiple controller system there can be one System Controller capable of asserting control becoming CIC Lightwave 04_09 REMOTE OPERATION Basic GPIB Concepts GPIB Cable Connections Standard GPIB connectors can be connected together stacked allowing you to configure the system linearly or in a star configuration Device B Device A Device B Device C Device D linear configuration Device C Device D star configuration Figure 3 1 GPIB Cable Connections The GPIB Connector The standard GPIB connector consists of 16 signal lines in a 24 pin stackable connector The extra pins are used
152. ount described in the first example three times with 5 seconds between incremental steps LAS STEP 1 LAS Mode P Las INC action The power set point is incremented by 0 1 mW LDC 3744C or 0 01 mW LDC 3724C or LDC 3714C LASer LDI I Parameters Notes Examples LDI DEVICE DEPENDENT FRONT PANEL The LASer LDI command sets the laser control current An nrf value which represents the laser output current in mA Set point is the same for both low and high bandwidth output modes Las LDI 400 action sets the laser output current to 400 00 mA LAS Idi 1000 action sets the laser output current to 1000 0 mA LDC 3700C Series 89 90 COMMAND REFERENCE Command Reference LASer LDI DEVICE DEPENDENT FRONT PANEL The LASer LDI query returns the value of the measured laser current Notes Response is the measured laser output current for either low or high bandwidth modes This measurement is updated approximately once every 600 msec 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 LASer LDV C DEVICE DEPENDENT The LASer LDV command sets the laser voltage for calibration of the laser voltage measurement Parameters nrf value which represents the laser output voltage in volts Notes Set point is the same for both low and high bandwidth output modes and is entered onl
153. output current Notes The TEC load current is constantly measured and updated regardless of the TEC mode of operation This measurement is updated approximately once every 600 msec If an external booster is used the ITE measurement will remain zero as the internal output section is disabled in that case In local operation the ITE measured value is determined by pressing the ITE switch in the TEC DISPLAY area of the front panel and visually reading the value on the TEC display Examples TEC ITE response 2 43 means the measured TEC output current is 2 430 Amps Tecilte response 3 27 means the measured TEC output current is 3 270 Amps 04 09 LDC 3700C Series 7 123 COMMAND REFERENCE Command Reference TEC LIMit ITE C DEVICE DEPENDENT FRONT PANEL The TEC LIMit ITE command sets the TEC TE current limit value Parameters nrf value representing the limit value of the TE current in Amps Notes This value also limits the TEC booster output signal voltage to a value which is proportional to the TEC limit current approximately 1 V A Examples TEC LIM ITE 3 5 action the TEC current limit is set to 3 500 amps Tec Limit lte 4 0 action the TEC current limit is set to 4 000 amps TEC LIMit ITE DEVICE DEPENDENT FRONT PANEL The TEC LIMit ITE query returns the value of the TEC s TE current limit Notes The ITE limit value is in effect for all modes of TEC operation Examples TEC LIM ITE
154. perature limit This mode is useful if a fixed thermal load requires heating or cooling and absolute thermal control is not required Setting a positive current value is defined to produce cooling of the load while a negative value defines heating of the load Automatic Shut Off Conditions for TEC Output The following conditions will automatically cause the instrument to disable the TEC output High Temperature Limit Connecting pins 13 and 15 on the TEC connector external booster temperature limit switch e Booster Changed while Output is enabled see Chapter 5 Sensor Open while Output is enabled TEC Module Open while Output is enabled SENSOR SELECT Switch Moved while Output is enabled e Sensor Shorted while Output is enabled TEC mode changed while output is enabled 04 09 LDC 3700C Series 35 OPERATIONS Operating the TE Controller from the Front Panel TEC Error Indicators The LDC 3700C Series Laser Diode TEC Controllers indicate general TEC operational error conditions Each error condition results in a controller action as shown in the following table Table 2 3 TEC Error Indicators Error Condition Action Temperature limit TEMP LIMIT light flashes at 1 Hz Open sensor Output off SENSOR OPEN indicator LED flashes at 1 Hz TE Current limit TE CURRENT LIMIT light flashes at 1 Hz TE Module Open TE MODULE OPEN indicator LED flashes at 1 Hz not in effect when booster so
155. pplies current through the thermistor so that a temperature change results in a voltage change across the thermistor This voltage change is sensed by the controller and fed back to the control loop If you have the thermistor sensor selected then select an appropriate current range with the upper switch The 10 uA and 100 uA designations are current levels supplied by the controller The selected supply current depends on the thermistor operating temperature range and the required temperature resolution A general rule of thumb for a 10 thermistor is to use the 10 pA range for temperatures between 30 and 30 C and the 100 pA range for temperatures between 10 to 70 C For a more complete description of thermistor selection see our Application Note 2 titled Selecting and Using Thermistors for Temperature Control LDC 3700C Series Lightwave 04_09 OPERATIONS Operating the TE Controller from the Front Panel Table 2 2 SENSOR SELECT Switch Positions Switch Position Code 100 pA 01 10 pA 02 LM335 03 AD590 04 Setting Temperature Sensor Constants After the sensor type is selected it will be necessary to enter the sensor calibration constants into the controller for accurate conversion to actual temperature These constants are used in a temperature conversion equation to calibrate the TEC and are supplied with your thermistor s data sheet The Steinhart Hart equation is used to
156. pre calibration out of tolerance conditions is available upon request Calibration turn times are normally five business days or less On site calibrations can be performed around your production schedule night or day seven days a week Please contact ILX Customer Support see page xi for contact information for additional calibration information Calibration Overview There are several calibrations to completely calibrate the LDC 3700C Laser Diode Controller The Temperature Controller calibration consists of calibrating the temperature sensors and the TE module bipolar current source and TEC voltage measurement The TEC voltage calibration can only be done remotely The Laser Diode Current Source calibration consists of calibrating the current source in both ranges and both modes low and high bandwidth calibrating the PD Lightwave LDC 3700C Series 135 CALIBRATION AND TROUBLESHOOTING Calibration Overview monitor feedback ammeter and calibrating the forward voltage measurement The current limits are calibrated internally by the instrument as part of the calibration process Your LDC 3700C Series Controller can be calibrated with the case closed Calibrate the instrument every 12 months or whenever performance verification indicates that calibration is necessary such as differences between set point and measurement display values which exceed the accuracy specification Calibrate the instrument under laboratory con
157. put off connect a 1 O 20 W resistor across the TEC output terminals TE Module and TE Module 2 Connect a calibrated DMM across the load resistor You will be calculating TE 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 is the calculated current in Amps A 4 point probe resistance measurement is recommended 3 sure that the TEC output is off before entering the calibration mode Press the Communications LOCAL and TEC DISPLAY switches at the same time to place the Controller in TEC Current Calibration mode The Laser display blanks and the TEC display drives the output to a value of zero 0 000 amps as the Temperature Controller calibrates itself After 20 seconds the TEC controller drives the output to 2 000 amps Once stable the temperature controller is ready to enter the actual TE current value 4 Press and hold the PARAMETER SET switch and turn the Adjust Knob until the TEC display shows the correct value absolute value of the lrg measurement Release the PARAMETER SET switch to store the new calibration value into non volatile memory The Controller drives the TE output current to the negative value of 2 000 Amps 5 Repeat step 4 for the negative polarity of the TEC output current After the negative polarity value of the TEC output is entered the controller au
158. r the Laser Controller 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 AAS LIM Ix SET POINT 80 of FS 90 for LDC 3744C jAS LDI 1 Measure and record the resistance of a 1 20 W resistor a 4 point probe 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 2 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 I V R where V is the accurately measured voltage across the resistor and R is the accurately measured load resistance I is the actual Laser current in Amps 3 The LASER output must be on in order to enter the LASER I calibration mode Enter the LAS OUTPUT ON command to turn the LASER output on 4 d Enterthe LASER I calibration mode by issuing the LAS CAL LDI command The display will blank and the LASER display will indicate a current in mA 04 09 LDC 3700C Series 151 CALIBRATION AND TROUBLESHOOTING Calibration Overview 5 Input the first actual measured LASER output current as an lt nrf value gt via the LAS LDI nrf value command If this value is
159. range as indicated in the RANGE section When the blue LIM I is indicated by the accompanying LED the LASER display will be indicating the limit set point in mA for the controller s low range Press the PARAMETER SET push button and rotate the adjust knob clockwise to increase the limit set point value or counterclockwise to decrease the limit set point value Set the limit to 175 mA Once the SET push button is released the new parameter value is stored in non volatile memory TEC ms PARAMETER mmm LASER LIM Ire LMI LIM SELECT LIM CONST f LIMP GAIN CAL PD C3 SAVE SET RECALL 0000 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 Lightwave OPERATIONS Functions and Features 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 Now you are ready to modulate the laser injection current To enable the controller output in the LASER 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 i
160. rent UA Ppp laser power mW or V forward voltage V measurement or set point values The SET switch can be used to view the set point of any of the LASER DISPLAY parameters When the LASER DISPLAY SET switch is pressed a display set point value is indicated by the corresponding display mode enunciator flashing At this point the Controller is in Constant Current Mode 1 in the 200 mA range and the display is reading in mA Next we need to adjust the set point of the laser current source The controller can be changed to set point mode a couple of ways LASER DISPLAY 1 len Pro v SET Adjusting the Set Point To adjust the set point of the Controller current source to 150 mA set the instrument to LAS mode by pressing the appropriate push button in the ADJUST section of the front panel The LAS indicator will be illuminated Turn the adjust knob clockwise to increase the set point as indicated on the LASER display or counterclockwise to decrease the set point When the ADJUST knob is turned the controller automatically changes to set point mode indicated by the display mode enunciator flashing Before adjusting the set point check the LASER display for proper display mode the display mode determines which set point is being adjusted Adjust the set point to 150 mA Pressing the SET switch in the LASER LDC 3700C Series 21 OPERATIONS Operating from the Front Panel DISPLAY section
161. response 3 5 means the TEC output current limit is 3 500 amps Tec Limit lte response 4 0 means the TEC output current limit is 4 000 amps TEC LIMit THI C DEVICE DEPENDENT FRONT PANEL The TEC LIMit THI command sets the TEC high temperature limit value Parameters An nrf value which represents the upper bound of the TEC load temperature in Notes The THI limit value must be in the range 0 199 9 The THI limit value also becomes the maximum temperature set point The default setting of the TEC outoff enable register forces the TEC output to be shut off if the high temperature limit is reached See the TEC ENABle OUTOFF command Examples TEC LIM THI 100 action sets the TEC load temperature limit to 100 0 C Tec Lim thi 30 3 action sets the TEC load temperature limit to 30 3 C 124 LDC 3700C Series Lightwave COMMAND REFERENCE Command Reference TEC LIMit THI C DEVICE DEPENDENT FRONT PANEL The TEC LIMit THI query returns the value of the TEC load s high temperature limit where the response is the temperature limit set point value Notes The temperature limit is valid for R and T modes of TEC output operation In local operation the THI limit value is read by pressing the TEC PARAMETER SELECT switch until the LIM T indicator is lit and reading the value on the TEC display If the high temperature limit is set too low the TEC output may not be able to be turned on if
162. returns the status of the LAS DISPLAY I switch Notes In local operation the status of the switch is indicated by the enunciator next to the LASER display mA will be illuminated when the display is in mode Examples LAS DIS LDI response 0 means that the LASER DISPLAY switch is not currently active laser current is not displayed Las dis ldl response 1 means that the LASER DISPLAY I switch is currently active laser current may be displayed LASer DISplay V l LDV DEVICE DEPENDENT FRONT PANEL The LASer DISplay LDV command sets the laser display to show the laser forward voltage measurement Parameters None Notes The actual LASER V display is turned off automatically when another LASER DISPLAY selection is enabled Examples LAS DIS LDV action enables the LASER display for forward voltage values in Volts 04 09 LDC 3700C Series 79 COMMAND REFERENCE Command Reference LASer DISplay LDV DEVICE DEPENDENT FRONT PANEL The LASer DISplay LDV query returns the status of the LAS DISPLAY V switch Notes In local operation the status of the V switch is indicated by the enunciator next to the LASER display V will be illuminated when the display is in V mode Examples LAS DIS LDV response 0 means that the LASER DISPLAY V switch is not currently active laser voltage is not displayed LAS DIS LDV response 1 means that the LASER DISPLAY V switch is currently active laser
163. ries Lightwave 04_09 OPERATIONS ETE Operating the TE Controller from the Front Panel E GE TER E depending on the position of the back panel SENSOR SELECT switch When lre is pressed the A annunciator will illuminate and the display will show measured TE module current in Amps Likewise if the SET switch is pressed and R mode is selected the display will show the thermistor resistance set point value in kO or the LM335 set point voltage in mV not annunciated or the AD590 set point current in not annunciated depending on the position of the SENSOR SELECT switch on the rear panel If is selected and the SET push button is pressed the instrument will display the TE module current set point in Amps TEC DISPLAY Setting Temperature Controller Limits The LDC 3700C Controller is capable of protecting your thermoelectric TE modules The Temperature Controller current limit function LIM Ig limits the controller s output current so that the instrument does not provide more current than your TE module can safely handle During controller operation if the TEC current limit is reached the TE CURRENT LIMIT error indicator underneath the TEC display will flash The TEC current limit is displayed in Amps Note it is normal for the TE Current limit to be reached when the TEC output is first turned on Typically the TE current will be maximum in li
164. roller the controller offers trigger output signal The TTL pulse is initiated with any change in set point of the laser current source and after the analog output has settled 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 IEEE 488 2 GPIB Interface 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 set point commands in relation to the actual hardware function The INC and DEC commands have a fixed minimum step time of 20 ms which allows for the hardware initiation of a set point change and the settling of the output The LDI command does not 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 38 LDC 3700C Series Lightwave 04_09 OPERATIONS Functions and Features A standard BNC connector on the rear panel of the LDC 3700C Controller is available for connecting any standard BNC terminated cable DN IX Lightwave TE CONTROLLER
165. rrent low bandwidth Range low lowest per instrument model Limit 90 of FS full scale of range Set Point 8096 of FS 9096 for LDC 3744C 1 Measure and record the resistance of a 1 20 W resistor a 4 point probe 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 2 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 I V R where V is the accurately measured voltage across the resistor and R is the accurately measured load resistance I 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 the outputs of the Laser Current Source 3 Press the LASER MODE ON switch to turn the LASER output on The LASER output must be on in order to enter the LASER I calibration mode Lightwave CALIBRATION AND TROUBLESHOOTING Calibration Overview 4 Enter the LASER I calibration mode by pushing the Communications LOCAL and LASER DISPLAY I switches at the same time The TEC display will blank and the controller will drive the LASER current output to the set point and the LASER display will indicate output current in mA 5 Calcu
166. s 100 0 mW LDC 3714C 500 0 mW LDC 3724C and 5000 mW LDC 3744C Also in constant power mode the LASER current limit and voltage limit values are in effect Refer to the discussion on page 8 which describes how to set these limits Now the instrument is configured to operate in Constant Power Mode In the LASER MODE section enable the output of the laser current source by depressing the OUTPUT push button once The accompanying led labeled ON will illuminate indicating that the laser output is on and current is being driven to 26 LDC 3700C Series Lightwave OPERATIONS Operating from the Front Panel the laser The Controller s laser source will drive the laser to the Constant Power set point and maintain closed loop control with the PD current measurement LASER MODE O SELECT ET uew o OUTPUT 04 09 LDC 3700C Series 27 28 OPERATIONS Operating from the Front Panel LASER Error Indicators The LDC 3700C Series Laser Diode Current Source Controllers indicate general LASER operational error conditions Each error condition results in a controller action as shown in the following table Table 2 1 Laser 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
167. s Laser Diode Controller This reference contains useful information for both local and remote operation of the LDC 3700C In some references parentheses are used to signify the labeled area for a particular switch or LED indicator on the front panel For example TEC DISPLAY SET refers to the switch labeled SET in the TEC DISPLAY area of the front panel CAL COMMON Action Adjusts the internal analog to digital A D converter to reference points then reports results Results Zero OK Non zero calibration error Note A D referencing is performed each 10 minutes of inactive time Example CAL CLS Common Action Clears status event registers Event Status Event Status Enable and Error Queue Note Useful to clear registers before enabling service requests SRQ Example CLS DELAY lt nrf value gt DEVICE DEPENDENT Action The DELAY command causes the execution of commands to be delayed by a user defined time This command is similar to the WAI common command except that execution resumes after the specified number of milliseconds instead of waiting for the Operation Complete flag to be set Parameters An nrf value which represents the delay time in milliseconds Notes The Operation Complete flag is held false until the delay period elapses but the query will not execute until the delay period has elapsed This command is useful for creating delays which don t require a lot of program cod
168. s 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 lt 80 RH non condensing Operating temperature range of 0 C to 40 C Storage and transportation temperature of 40 C 70 C 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 which can result in death injury or damage to the instrument and other components x LDC 3700C Series Lightwave Caution Earth Visible and or refer to ground NU 227 invisible laser manual Terminal radiation Caution risk Protective Frame or of electric Conductor 2 hot chassis shock Terminal Terminal dh On In position of a bistable push control O 6 Off Out position of a bistable push control or The slash I only denotes that mains are on or 1 0 The circle only denotes that mains off WARRANTY
169. s similar to the status reporting registers However their outputs are not reported in the Status Byte Register Rather they go to the hardware which controls the output switching for that function LASER or TEC The events and conditions which may be set to cause the TEC and LASER outputs to be turned off are shown in Figure 3 6 on page 59 and Figure 3 7 on page 59 The default factory settings for these registers are shown in Table 3 4 These settings are not effected by the PSc Power On Status Clear command Table 3 4 Default Settings for Output Off Registers LASER Output Off Register TEC Output Off Register 0 disabled 8 N A 0 disabled 8 enabled 1 disabled 9 disabled 1 disabled 9 disabled 2 N A 10 disabled 2 N A 10 enabled 3 enabled 11 enabled 3 enabled 11 N A 4 N A 12 N A 4 N A 12 N A 5 N A 13 N A 5 enabled 13 N A 6 N A 14 N A 6 enabled 14 N A 7 N A 15 N A 7 enabled 15 N A 58 LDC 3700C Series Lightwave 04_09 Bit Reference REMOTE OPERATION Command Syntax 11 0 LASER Output Off Register 216 5 413 2 1 o LASER Output Enable Register Turn Output Off LASer ENABIe OUTOFF lt nrf gt LASer ENABle OUTOFF Figure 3 6 LASER Output Off Register 0 LASER Current Limit 8 N A
170. s the appropriate command or query written above or below the register representation For example the LASER Condition Register may be queried via the LL ASer COND query The condition or event registers are logically ANDed with their respective enable registers These bits are then logically ORed to form a summary message in the status byte for that particular register 04 09 LDC 3700C Series 55 REMOTE OPERATION Command Syntax 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 signal will be generated upon completion of the currently processed commands This may be used to initiate service request routines which depend on the completion of all previous commands For example the user may set the TEC output to 30 enable an SRQ on Operation Complete set ESE 1 and SRE 32 and have an SRQ handling routine in the user s software which reads a new measurement after the 30 value has been reached This allows the use of the operation complete features of the LDC 3700C Series Laser Diode Controller without the need for program looping or polling which can tie up the communications Operation Complete on the LDC 3700C Series Laser Diode Controller is defined as
171. s the constant sensor mode resistance voltage or current TEC R NONE Returns the measured temperature sensor value TEC SEN NONE Returns the position of the SENSOR SELECT switch TEC SET ITE NONE Returns the constant ITE TEC current set point TEC SET R NONE Returns the constant R temperature sensor value set point TEC SET T NONE Returns the constant T temperature set point TEC T 1 Used to set the TEC constant T temperature set point TEC T NONE Returns the TEC measured temperature value TEC TOL 10r2 Used to set the TEC set point tolerance value and time period value TEC TOL NONE Used to return the TEC set point tolerance value and time period value TEC V 1 Used to enter the TEC voltage value during calibration TEC V NONE Used to return the TEC voltage measurement value TERM 1 Used to add a carriage return to the device terminator TERM NONE Returns the status of the TERM command TIME NONE Returns the elapsed time since the instrument was last powered up TIMER NONE Returns the elapsed time since the timer was last reset TST Initiates an internal self test and returns a response when complete WAI Prevents executing any further commands until the No Operation Pending flag is true LDC 3700C Series Lightwave COMMAND REFERENCE Command Reference Command Reference The following pages contain a reference for the device dependent commands of the LDC 3700C Serie
172. sensor so that the temperature measurement is as accurate as possible 1 Set the SENSOR SELECT switch back panel to the AD590 position the TEC display code is 04 Connect a precision 16 8 metal film resistor and multimeter in series at the sensor input of the Temperature Controller 15 pin connector on the rear panel Sensor and Sensor terminals Configure the multimeter to measure current in pA Enter the TEC sensor calibration mode by pushing the Communications LOCAL and TEC DISPLAY R switches at the same time The TEC display will become blank for 2 seconds then the sensor code SENSOR SELECT switch position value will be displayed for 2 seconds After this the TEC display will indicate sensor reference current in not annunciated Press and hold in the PARAMETER SET switch and turn the ADJUST knob until the TEC display indicates the same current as shown on the multimeter Release the PARAMETER SET switch to store the new value into non volatile memory After the SET switch is released the LDC 3700C Series Laser Diode Controller will return to its former state before calibration LM335 Sensor Calibration The following procedure is for calibrating the LM335 sensor so that the temperature measurement is as accurate as possible 1 1407 LDC 3700C Series Set the SENSOR SELECT switch back panel to the LM335 position the TEC display code is 03 Connect a precision 6 8 metal film resi
173. should be set to 0 for lpp operation modes Otherwise the value of this parameter is used to convert between lpp and Ppp values The units of this parameter are microamps milliwatt 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 microamp milliwatt Therefore a photodiode feedback current of 1 microamp will cause the Ppp display to read 1 milliwatt 04 09 LDC 3700C Series 73 COMMAND REFERENCE Command Reference LASer CAL MD N PD DEVICE DEPENDENT FRONT PANEL The LASer CALMD query returns the value of the laser s photodiode feedback responsivity CAL PD parameter setting Notes If this value is 0 the LDC 3700C Series Laser Diode Controller will be set to operate in constant lap mode and the lp set point value will be in effect If this value is non zero the LDC 3700C Series Laser Diode Controller will be set to operate in constant mode and the Pp set point value will be in effect If this value is 0 the front panel Ppp will display and no Ppp value can be calculated Examples LASER CALMD response 0 means the LDC 3700C Series Laser Diode Controller is set for operation in constant lpp mode if P mode is also selected Las Calmd response 1 1 means the LDC 3700C Series Laser Diode Controller is set for operation in constant Ppp mode if P mode is also selected and the responsivi
174. 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 PD 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 PD monitor power LAS DIS MDP NONE Returns status of photodiode monitor power display on off LAS DIS PARAM NONE Enables LASER display to show parameter values 64 LDC 3700C Series Lightwave 04_09 COMMAND REFERENCE Remote Command Reference Summary E Table 4 1 Remote Command Summary Reference List Name Parameters Function LAS DIS SET NONE Shows the LASER display set point corresponding to mode LAS DIS SET NONE Returns status of LASER set point 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 OUTOFF 1 Sets the enable register for LAS conditions which 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 set poi
175. st the instrument is ready to operate and is configured to the state it was in when the power was last shut off Lightwave LDC 3700C Series 13 14 OPERATIONS The Power On State You can choose to clear the last saved instrument state by recalling the default values These values are stored in BINS to which you can save or recall instrument configurations described in more detail in Chapter 5 BIN 0 contains all of the default configurations listed below 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 Laser Display See Troubleshooting on page 155 for a list of error codes and actions to take when your instrument indicates these errors 37x4C Series Default Configuration LDC 3700C Series GPIB mode in LOCAL via front panel or in REMOTE via GPIB RECALL BIN number 0 TEC and LASER adjust not selected LASER DISPLAY enabled in mode LASER display showing measured current Constant I low bandwidth mode selected LIM V 10 Volts LIM I high range 1000 125 25 mA 3744C 3724C 3714C LIM I low range 500 50 mA 12 5 mA 3744C 3724C 3714C LIM P 5000 1000 200 mw 3744C 3724C 3714C LASER output off LASER Tolerance values 10 0 mA 1 0 s 3744C LASER STEP value 1 LASER I Set Point 0 mA LASER Ppp Set Point 0 mW LASER IPD Set Point 0 pA CAL PD 0 mA mW PARAMETERS not selected
176. stant load temperature operating mode TEC OUTput Parameters Notes Examples LDC 3700C Series DEVICE DEPENDENT FRONT PANEL The TEC OUTput command turns the TEC output on or off An nrf value 1 on 0 off 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 TEC OUTPUT 1 action turns the TEC output on Tec Out 0 action turns the TEC output off Tec Out OFF action turns the TEC output off Lightwave COMMAND REFERENCE Command Reference TEC OUTput Notes Examples DEVICE DEPENDENT FRONT PANEL The TEC OUTput query returns the status of the TEC output switch Although the status of the switch is on the output may not have reached the set point value Tec Out response 0 means the TEC output switch is off TEC output is off TEC OUT response 1 means the TEC output switch is on TEC output is on TEC R Parameters Note Examples DEVICE DEPENDENT FRONT PANEL The TEC R command sets the TEC s constant thermistor resistance or linear sensor reference set point An nrf value which represents the thermistor resistance set point value the AD590 current set point in pA or the LM335 voltage set point in mV depending on the selected sensor type The R set point is used to control the TEC output in R mode only Using the R mode th
177. stor and the multimeter in parallel to the sensor input of the Temperature Controller 15 pin connector on the rear panel Sensor and Sensor terminals Configure the multimeter to measure voltage in mV Enter the TEC sensor calibration mode by pushing the Communications LOCAL and TEC DISPLAY R switches at the same time The sensor code SENSOR SELECT switch position value will be displayed for two seconds After this the TEC display will indicate sensor reference voltage in mV not annunciated Press and hold in the PARAMETER SET switch and turn the ADJUST knob until the TEC display indicates the same voltage as shown on the multimeter Release the PARAMETER SET switch to store the new value into non volatile memory After the SET switch is released the LDC 3700C Series Laser Diode Controller will return to its former state before calibration Lightwave CALIBRATION AND TROUBLESHOOTING Calibration Overview ITE Current Calibration This procedure is for calibrating the ITE bi polar constant current source This procedure calibrates the zero current set point automatically then it automatically drives the TE current output to internally set limits of 2 amp When each of these values is reached and is stable the user enters the actual value of the current as measured by an external DMM The LDC 3700C Series Laser Diode Controller then automatically calibrates the TEC current source and limits 1 With the out
178. sued If the Laser Diode Current output is on when this command is issued the LDC 3700C Series Laser Diode Controller will generate error 515 and the range will not be changed LAS RAN 2 action sets the laser output drive current range to 200 mA LDC 3724C only Laser range 1 action sets the laser output drive current range to 100 mA LDC 3714C only or 1000 mA LDC 3744C only LASer RANge COMMON Notes Examples DEVICE DEPENDENT FRONT PANEL The LASer RANge query returns the value of the Laser Drive Current range The resolution and accuracy of the laser limit current are dependent on the Laser Drive Current output range LAS RAN response 1 means that the Laser Drive Current range is 100 mA LDC 3714C only LAS range response 2 means that the Laser Drive Current range is 200 mA LDC 3724C only or 2000 mA LDC 3744C only LASer SET LDI Notes Examples DEVICE DEPENDENT FRONT PANEL The LASer SET LDI query returns the constant value which is used for both output ranges and both bandwidths In local operation the constant set point is read by selecting or IHBW mode pressing the SET switch in the LASER DISPLAY area of the front panel and then visually reading the LASER display LAS SET LDI response 50 0 means the laser output current set point value is 50 0 mA Laser set ldi 1200 0 means the laser output current set point value is 1200 0 mA LDC 3700C
179. t the response from the Controller is 1 5 Once the TEC R value is sent the Controller will return to its former state before calibration The oPc query may be used after the TEC value is sent to determine when the calibration is completed 148 LDC 3700C Series Lightwave CALIBRATION AND TROUBLESHOOTING Calibration Overview l Current Calibration The following procedure is for calibrating the lyg bi polar constant current source This procedure calibrates the zero current set point then it automatically drives the TE current output to internally set limits of 2 000 amps When each of these values is reached and is stable the user enters the actual value of the current as measured by an external DMM The LDC 3700C Series Laser Diode Controller then automatically calibrates the TEC current source and limits 1 With the output off connect a 1 O 20 W resistor across the TEC output terminals TE Module and TE Module 2 Connect a calibrated DMM across the load resistor You will be calculating TE 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 is the calculated current in Amps A 4 point probe resistance measurement is recommended 3 The TEC output must be off in order to enter the Irg calibration mode Enter the TEC OUTPUT OFF command 4 Enter the TEC
180. t values or set point values The display annunciator mW will illuminate when Ppp is selected LASER DISPLAY Adjust the Constant Power set point of the controller to 1 00 mW To do this set the instrument to LAS mode by pressing the appropriate push button in the ADJUST section of the front panel Turn the adjust knob clockwise to increase the set point as indicated on the LASER display or counterclockwise to decrease the set point When the ADJUST knob is turned the controller automatically changes to set point mode indicated by the display mode enunciator flashing Before adjusting the set point check the LASER display for proper display mode The display mode determines which set point is being adjusted Adjust the set point to 1 00 mW Pressing the SET switch in the LASER DISPLAY section will also change the controller to set point mode Make sure that the mW annunciator next to the display is illuminated before adjusting the set point After an adjustment has been made and the LASER DISPLAY SET switch and ADJUST knob are released the SET mode will time out in three seconds The new set point will be stored in non volatile memory If the original display mode LDC 3700C Series 25 OPERATIONS Operating from the Front Panel differed from the newly adjusted set point the LASER display will revert to the original display mode I Ipp or Ppp
181. t Type Bipolar constant current source Compliance Voltage gt 8 VDC Short Circuit Output Current 4 Amps Maximum Output Power 32 Watts Current Noise and Ripple lt 1 mArms Current Limit Range 0 to 4 Amps Current Limit Set Accuracy 0 05 Amps Control Algorithm Smart Integrator Hybrid PI TEMPERATURE SENSOR Types Thermistor NTC 2 wire IC Temperature Sensor AD590 LM335 RTD Sensor Pt 100 ohm RTD Thermistor Sensing Current 10 uA 100 pA Sensor Bias AD590 8 V LM335 1 mA RTD 0 8 mA Useable Thermistor Range 25 to 450 000 typical Typical Sensor Output AD590 Current Output 25 C 298 2 uA 1 LM335 Voltage Output V 25 C 2 73 V V 10 mV K RTD Pt459 Resistance R 25 C 109 73 Q User Calibration Thermistor Steinhart Hart 3 constants IC Sensors RTD Two point 8 7 LDC 3700C Series Lightwave 04_09 INTRODUCTION AND SPECIFICATIONS General LDC 3700C Specifications TEC MEASUREMENT DISPLAY Range Resolution Accuracy Temperature 10 pA Setting 100 0 C to 199 9 C 0 01 C 0 1 C 100 pA Setting 100 0 C to 199 9 C 0 01 C 0 05 C Thermistor Resistance 10 pA Setting 0 01 to 450 00 kO 0 01 ka 0 05 100 pA Setting 0 001 to 45 000 0 001 ka 0 05 TE Current 4 000 to 4 000 A 0 001 A 0 04 A Voltage remote only 10
182. t contain all of the letters shown in upper case in the command definition Optional letters shown in lower case for some device dependent commands in the command reference Chapter 4 are useful for clarity but must be in the correct sequence A single white space must separate a command from its parameters or data White space is normally the space character space bar Other control characters are also interpreted as white space Do not use white space before the question mark in a query command LDC 3700C Series 51 REMOTE OPERATION Command Syntax The instrument ignores CR Carriage Return as white space The LDC 3700C terminates its responses with lt CR gt lt NL gt lt END gt unless you use the TERM command to change it You can put more than one command on the same line same command string if you separate them with a semicolon The remote communications protocol uses a flexible representation for numeric parameters integer floating point or engineering scientific notation There are no default values for omitted parameters Some device dependent commands are compound commands in which the first mnemonic opens a path to a set of commands relating to that path The second mnemonic then defines the actual command Following are examples of invalid syntax command strings that will produce errors Table 3 2 Invalid Syntax Command Strings COMMAND COMMENT EC MO
183. t point After a few seconds the Controller will be ready for the actual lp current to be entered via the LAS MDI nrf value command The measured value of the current should not be entered until the Controller is ready to receive it The Controller will be ready to receive the current value when after a LAS CAL MDI query is sent the response from the Controller is 1 Once the actual lap value is entered via the LAS MDI nrf value command the Controller will store the new calibration value in non volatile memory It will then set the output to approximately one fourth 1 4 of the original current For example if the first calibration set point was 4000 pA the second set point will be about 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 Once the second actual lpp 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 LDC 3700C Series 153 CALIBRATION AND TROUBLESHOOTING Calibration Overview Laser Forward Voltage Measurement Calibration The following procedure is for calibrating the LASER voltage measurement Configure the Controller in the following manner for the Laser Controller Voltage
184. t the load depending on the difference between the set point and the actual temperature Press the OUTPUT switch once to enable the TEC output and again to disable the output The default condition for the TEC output is off when the instrument is first powered up TEC MODE CT OR SELECT LJ he o OUTPUT 34 LDC 3700C Series Lightwave OPERATIONS Operating the TE Controller from the Front Panel Operating the Controller in Resistance Sensor Mode R Selecting R in the mode section of the front panel selects constant resistance mode In this mode the temperature controller will maintain temperature so that the temperature sensor s resistance current or voltage remain constant depending on whether the sensor is a thermistor AD590 or LM355 This mode is useful if the sensor constants are not known or the sensor values are only known at the operating temperature When using this operating mode the control setpoint must be in terms of the sensor output units namely pA or mV Operating the Controller in Constant Current Mode Selecting l7g in the TEC mode section of the front panel selects constant current mode In this mode the temperature controller will output a constant current when the output is enabled regardless of temperature The output will only be disabled by manually turning the output off or if the temperature hits the high tem
185. table base and rotate the front legs downward until they lock into position Rack Mounting The LDC 3700C Series Laser Diode Controller can be mounted in a standard 19 inch rack with the optional rack mount kits The kits contain a rack mount flange and hardware for mounting on either side of the enclosure All rack mount accessory kits contain detailed mounting instructions Operating the LDC 3700C Laser Diode Controller Now that the LDC 3700C Laser Diode Controller is installed and ready for use you can begin to learn about its operation The following figures are front and rear photographic copies showing the functional keypad groupings rear panel connectors and so on Use these figures to familiarize yourself with the LDC 3700C Controller After that use Chapter 2 for fundamentals of operating the controller LDC 3700C Series 3 INTRODUCTION AND SPECIFICATIONS Installing the LDC 3700C Figure 1 1 LDC 3700C Series Controller Front View CURRENT SOURCE o MIB IX Lightwave GPIB de BOZEMAN MONTANA 59715 USA TE CONTROLLER CE SERIAL d THERM RANGE TIE Orit LINE VOLTAGE 100 P20 2 I 100 4 ap mes RATING 3 0A T 3 154 SENSOR SELECT 6 gt lt THERM A N A 4 3 1 335 4 1590
186. tage Adjustment For applications where you need to have critical protection of the laser we recommend the following Using a 1 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 LASER DISPLAY V push button to see the voltage At about 0 25 Volts below the LASER voltage limit value the VOLTAGE LIMIT warning indicator will become lit on the LASER display Continue to adjust the current up until the voltage limit is reached and the output is shut off Record the voltage at which 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 Volts the actual voltage where it shuts off may be 4 9 Volts This error term of 0 1 Volts should be considered when setting the LASER compliance voltage limit LASER DISPLAY ul 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 Using the LDC 3700C Controller s Trigger Function For applications where you need to synchronously initiate a measurement task from a remote instrument with the LDC 3700C Cont
187. tate 4096 N A 32 N A 8192 N A 64 N A 16384 N A 128 Open Circuit 32768 N A Notes 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 IEEE488 2 specification Examples 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 04 09 LDC 3700C Series 85 COMMAND REFERENCE Command Reference LASer ENABle EVEnt COMMON DEVICE DEPENDENT FRONT PANE The LASer ENABle EVEnt query returns the value of the status event enable register of the LASER operations 1 LASER Current Limit 256 Output is Shorted 2 LASER Voltage Limit 512 Output Changed to be In Out of Tolerance 4 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 N A 16384 N A 128 Open Circuit 32768 N A Notes The enabled LASER events can be set by using the LASer ENABle EVEnt command
188. tely once every 600 msec Examples 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 20 uA of photodetector current but photodiode monitor current is not controlling the laser output current 04 09 LDC 3700C Series 95 96 COMMAND REFERENCE Command Reference LASer MDP Parameters Notes Examples DEVICE DEPENDENT FRONT PANEL The LASer MDP command sets the value of the optical power set point in mW if the CALMD CAL PD responsivity is greater than 0 An nrf value which represents the photodiode feedback power in mW 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 set point would be used Las Map 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 Notes Examples DEVICE DEPENDENT FRONT PANEL The LASer MDP query returns the value of the laser photodetector power measurement in mW 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 msec Las Mode MDP Las Calmd 460
189. temperature value EC V NONE Returns the TEC voltage measurement value Status Reporting This section contains information that is relevant for understanding instrument error and status 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 the instrument is useful for programming synchronization The Output Off Register section also contains information on configuring the conditions which force the laser current source and or TEC output off Event and Condition Registers In addition to the required IEEE488 2 status reporting structures the LDC 3700C remote interface provides Event and Condition Registers for TEC and LASER controller operations The Event Registers are used to report events which occur during the operation of the LDC 3700C Series Laser Diode Controller Events differ from conditions in that events signal an occurrence once and are not reset until the Event Register is queried or the LDC 3700C Series Laser Diode Controller 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 5 on page 57 shows the status reporting scheme of the LDC 3700C Series Controller Each of the registers which may be accessed by a command or query ha
190. the PARAMETER SET push button and rotate the adjust knob clockwise to increase the limit set point value or counterclockwise to decrease the limit set point value Set the limit to 175 mA Once the 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 22 7 LDC 3700C Series Lightwave 04_09 OPERATIONS Operating from the Front Panel circuitry is fully independent of the main current control the current limit can be adjusted safely even while the LASER output is active TEC mmm PARAMETER mm LASER I LIM Ire LIMI C3 LIM SELECT LIM I C3 CONST UMP C3 GAIN CAL PD I SAVE RECALL Set Compliance Voltage Limit A new feature of the 3700C Series instruments 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 LASER section of th
191. tion on page 56 for conditions about setting the operation complete flag Sequential Overlapped Commands All device dependent commands are executed in an overlapped manner subsequent commands may begin before the current command is completed Some common commands are sequential the next command must wait until this command is completed All device dependent commands are executed in an overlapped manner except the DELAY command which is sequential The operation complete flag is set after the conditions outlined in the Operation Complete Definition have been satisfied The 04 09 common command is an example of a sequential command which 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 which 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 ensures the OPC flag is never set prematurely Query Response Timing Query responses are evaluated at the time the query request is parsed and not at the time the response message is sent In most cases this does not create a problem since the time between parsing a query and sending its response is smal
192. tomatically calibrates its current limits and set points indicated by the flashing TE Current Limit indicator The controller then returns to the state before calibration 04 09 LDC 3700C Series 141 LDC 3700C Series CALIBRATION AND TROUBLESHOOTING Calibration Overview Local Calibration of the Laser Current Source There are three calibration adjustments required for the LASER current source of the LDC 3700C Series Laser Diode Controller 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 lpp feedback circuits The LDC 3700C Series Laser Diode Controller implements a two point calibration for the Laser current source Two currents approximately 8096 and 2096 of FS are applied to a test load and the resulting actual currents are fed back by the user to the Controller The Laser Controller calibration program uses the two sets of data to calculate new calibration constants These calibration constants are used to set the actual current output of the current source Current Source Calibration The following procedure is for calibrating each range of the current source Start with the low range After calibration is complete in this range switch to the high range and repeat the procedure Configure the Laser Controller in the following state Function State Laser Mode constant cu
193. tor identifies when the controller is in remote operation mode When the instrument is in REMOTE mode pressing the LOCAL switch returns the instrument to LOCAL control mode unless the Local Lockout state has been activated by the host computer Local Lockout disables all LDC 3700C Series Laser Diode Controller front panel switches until this condition is changed by the host computer When the instrument is put in Local Lockout Mode by the host computer the REMOTE indicator will flash at a 1 Hz rate to indicate that the front panel is completely disabled by Local Lockout The TALK LISTEN indicator illuminates when the instrument is communicating over USB or the GPIB bus 04 09 LDC 3700C Series 47 1 REMOTE OPERATION Command Syntax Command Syntax This section describes command syntax and structure You need this information to effectively write USB or GPIB control programs The syntax of remote commands follow the rules defined in the ANSI IEEE 488 2 1987 standard Letters Any remote command or query must contain all of the letters which are shown in upper case in the command definition Some of the device dependent commands include additional optional letters shown in lower case in the command reference Chapter 4 Command Reference Upper lower case does not matter it is used in this manual to identify optional letters The optional letters must be in the correct sequence Some examples of what works and what does not
194. tric TE modules of your laser or laser mount and the temperature sensor There are connections provided for TE module TE module shield TE sensor digital and analog ground and a special TE booster feature connection The pinout diagram for this connector is shown in Figure 2 3 1 2 TE Module 9 Analog Ground 3 4 TE Module 10 Control Signal 11 Voltage Limit 5 TE Shield 12 Current Limit 6 Temperature Sensor Shield 13 Temperature Limit TT t emperature Sensor 14 Booster 8 Temperature Sensor 15 Digital Ground teconn 1 Figure 2 3 Rear Panel TEC Connector Pins 1 and 2 and 3 and 4 are connected together in pairs internally to allow high current flow to the TEC module Peltier device Pins 7 and 8 are connected to the sensor i e thermistor Pins 9 through 15 are normally not used and should be left unconnected They are intended for use with an external TE Booster TEC Grounding Considerations The TEC outputs of the LDC 3700C Series are isolated from chassis ground allowing either output terminal to be grounded If a terminal is grounded make sure to connect it only to the Earth ground A CAUTION Connecting one of the TEC output terminals to analog or digital ground causes catastrophic damage to the instrument For the TEC connector if any one terminal pin is grounded then no other terminal pin can be grounded Do NOT connect the Sensor and TE Module to the same ground damage to th
195. ture Controller Sensor Selection 30 Setting Temperature Sensor Constants 31 Setting TE Control Loop Gain 32 Setting Temperature Controller Limits 33 Adjusting the Temperature Set 34 Operating the Controller in Resistance Sensor Mode R 35 Operating the Controller in Constant Current Mode ng n 35 Automatic Shut Off Conditions for TEC Output 35 TEC Error Indicators 36 Functions and Features 37 ii LDC 3700C Series Lightwave Saving and Recalling from the Front Panel 37 Using the Laser Compliance Voltage Adjustment 38 Using the LDC 3700C Controllers Trigger Function 38 Modulating the Controller Laser Current Source 39 Boosting the TE Controller 41 Chapter 3 Remote Operation USB Operations vas esas he tei oe Fasc ue ORO CIR ROS 43 USB Driver Installation 43 Basic GPIB Concepts 44 Data and Interface Messages 44 Talkers Listeners and Controllers 44 GPIB Cable
196. ty is set to 1 1 pA mW 1 1 uA of photodiode feedback current represents 1 mW of optical power LAS CAL CONST DEVICE DEPENDENT The LAS CAL CONST query returns a stored calibration value It is intended for factory use only LASer CAL LDI I DEVICE DEPENDENT FRONT PANEL The LASer CAL LDI command is used to enter the LASER current set point measurement and limit in low bandwidth mode calibration mode 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 LDC 3700C Series Laser Diode Controller will allow calibration of the current set point 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 ls and turn the LASER output on before performing the calibration for that bandwidth Calibration is performed at the current set point wherever it is set If the LASER output is not on E 517 is displayed In remote operation the LASer CAL LDI query may be used to determine if the LDC 3700C Series Laser Diode Controller is ready for the user to enter a value Examples Las CAL Ldl action the LDC 3700C enters calibration mode for LASER current Las Cal LDI action the LDC 3700C enters calibration mode for L 7A LDC 3700
197. urce is used TE Compliance Voltage Limit TE CURRENT LIMIT light flashes at 2 Hz 36 LDC 3700C Series Lightwave OPERATIONS Functions and Features Functions and Features This section introduces you to the LDC 3700C Controller s functions and operating features such as event triggering analog modulation of laser injection current TEC boosting and Save and Recall Saving and Recalling from the Front Panel For applications where you might need to alternate between particular instrument configurations the LDC 3700C Controllers offer 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 which 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 which are periodically repeated For example using the configuration described in Chapter 2 where the controller is operating in Constant Current and Temperature modes the instrument parameters saved by using the SAVE function would be Constant Current Mode 200 mA range a limit set point of 175 mA a laser current set point of 150 mA Display Mode I Constant Temperature mode thermistor constants C1 C2 and a temperature set point of 35 a loop gain of 30 temperature limit of 40 and a TE current limit of 2 A Once this set up is save
198. values are reached and are stable the user enters the actual value of the monitor current measured with a DMM The LDC 3700C Series Laser Diode Controller then automatically calibrates the LASER feedback circuits Configure the Controller in the following manner for the Laser Controller calibration Function State Laser Mode P constant power Laser Range High Range CAL PD set equal to zero LASER LIMIT 90 of FS full scale of range Intitial Ipp Set POINT 4000 pA 1 Connect a voltmeter set to autorange DCV mode between laser output pins 6 and 7 Black to pin 6 and red to pin 7 Adjust PD bias pot until voltmeter reads 3 5V 2 With the LASER output off connect a calibrated ammeter to the PD Anode output of the Laser Controller output connector 9 pin on rear panel and connect the circuit of Figure 5 1 on page 137 to the LASER and PD outputs with the correct load resistor for the controller model you are calibrating See Table 5 2 on page 138 Note If a precision ammeter is not available use a zero Ohm jumper in place of the ammeter Then place a calibrated 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 I V R where V is the accurately measured voltage across the resistor and R is the accurately measured load resistance I is the actual pd current to be measured by the controller
199. void multiple earth grounds in the circuit Multiple earth grounds may provide circuit paths that induce spurious currents in the photodiode feedback circuit and output leads 04 09 LDC 3700C Series 15 OPERATIONS A CAUTION Connecting to the Laser Controller If a circuit opens during laser operation while the LASER is ON the laser may be damaged by a momentary circuit break and remake before the final circuit break The cable connections to the laser must be secure enough that they will not open circuit should they be jostled or bumped OUTPUT 3700B Series Laser Diode Controller Earth Ground 777 3700B Series Laser Diode Controller Earth Ground 3700B Series Laser Diode Controller Earth Ground 777 3700B Series Laser Diode Controller Earth Ground 777 Common Laser Cathode Photodiode Cathode Common Laser Anode Photodiode Anode Common Laser Cathode Photodiode Anode Common Laser Anode Photodiode Cathode Figure 2 1 Laser Diode Connection Configurations LDC 3700C Series Lightwave OPERATIONS Connecting to the Laser Controller Connecting the Laser Current Source The 9 pin connector marked CURRENT SOURCE on the back panel of your Controller is used to connect your laser diode to the controller There are connections provided for
200. voltage in Volts 4 Enter the measured voltage in volts Press and hold in the PARAMETER SET switch and turn the ADJUST knob until the LASER display indicates the measured voltage 5 Once the actual voltage value is entered the Controller will set the current to approximately one fourth 1 4 of the original value It will then expect the second calibration voltage point 6 Input the second actual measured LASER forward voltage 7 the second actual voltage value is entered the Controller stores the new calibration constants 146 LDC 3700C Series Lightwave 04_09 CALIBRATION AND TROUBLESHOOTING Calibration Overview Remote Calibration of the LDC 3700C Controller The LDC 3700C Series Controllers can be calibrated remotely via the GPIB Interface The following procedures are general guidelines for writing a program to calibrate your instrument The operation complete flag bit O of the Standard Event Status Register may be used to trigger a service request This type of interrupt is enabled by setting bit 0 of the Service Request Enable 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
201. when constant R mode is in effect Examples TEC SET R response 3 4 means the R set point is 3 400 or 3 40 uA or 3 4 mV depending on the SENSOR SELECT switch position Tec Set R response 4 0 means the R set point is 4 000 or 4 00 uA or 4 0 mV depending on the SENSOR SELECT switch position 128 LDC 3700C Series Lightwave COMMAND REFERENCE Command Reference TEC SET T Notes Examples TEC T Parameters Notes Examples DEVICE DEPENDENT FRONT PANEL The TEC SET T query returns the TEC constant temperature set point value in The TEC output is controlled to this set point value only when constant T mode is in effect response 33 4 means the constant T set point is 33 4 C Tec Set t response 4 0 means the constant T set point is 4 0 C DEVICE DEPENDENT FRONT PANEL The TEC T command sets the TEC s constant temperature set point An nrf value which represents the TEC temperature in C The TEC temperature is controlled to this set point only when the TEC is operated in T mode If the a maximum temperature limit is set see TEC LIMit THI on page 124 this limit becomes the maximum set point value as well Tec T 20 action sets the TEC temperature set point to 20 0 C TEC MODE T TEC T 25 3 action sets the TEC temperature set point to 25 3 C The output is controlled to this value if the output is on TEC T Notes Examples
202. will also change the controller to set point mode Make sure that the mA enunciator next to the display is illuminated before adjusting the set point After an adjustment has been made and the LASER DISPLAY SET switch and ADJUST knob are released the SET mode will time out in three seconds The new set point will be stored in non volatile memory If the original display mode differed from the newly adjusted set point the LASER display will revert to the original display mode I Ipp or Ppp Note When adjusting any LASER parameter display mode or operating mode the LAS indicator in the ADJUST section must be lit We are not quite ready to turn on the laser One of the laser protection features our controllers 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 set point and the controller mode Constant Current or Constant Power Set Current Source Limit To set the current source limit use the SELECT push button in the PARAMETER LASER section of the front panel to select LIM 1 You will notice there are two LIM I selections one in blue text and the other in black text The blue text limit selection corresponds to the blue text current source range as indicated in the RANGE section The LASER display will be indicating the limit set point in mA indicated by the LIM I LED for its corresponding range Press and hold
203. will drive the output current to a value of about 0 12 Amps so that the TEC voltage will be about 6 00 volts 6 Repeat step 4 After the value for the positive polarity of the TEC voltage is entered the Controller will automatically store the new calibration values for TEC voltage measurement 150 LDC 3700C Series Lightwave CALIBRATION AND TROUBLESHOOTING Calibration Overview Current Source Calibration There are three calibration adjustments required for the LASER current source of the LDC 3700C Series Laser Diode Controller 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 LDC 3700C Series Laser Diode Controller implements a two point calibration for the Laser 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 Controller The Laser Controller 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 Start with the low range After calibration is complete in this range switch to the high range and repeat the procedure Configure the Controller in the following manner fo
204. y for LDV calibration Examples Las LDV 4 action enters a value of 4 000 volts LAS Idv 1 025 action enters a value of 1 025 volts LASer LDV C DEVICE DEPENDENT The LASer LDV query returns the value of the measured laser voltage Notes This measurement is updated approximately once every 600 msec Examples LAS Idv response 3 03 means the measured laser output voltage is 3 03 volts Laser LDV response 1 0 means the measured laser output voltage is 1 000 volt LASer LIMit Il Parameters Notes Examples LDC 3700C Series DEVICE DEPENDENT FRONT PANEL The LASer LIMit 11 command sets the LASER current limit value for the 100 mA range on the LDC 3714C and the 2000 mA range on the LDC 3744C Not applicable for LDC 3724C An nrf value which represents the LASER limit current in mA The current limit is in effect in all modes of operation of the laser output with respect to the output range low high LAS LIM I1 80 action the LASER current limit is set to 80 mA Laser Limit 11 60 action the LASER current limit is set to 60 mA Lightwave COMMAND REFERENCE Command Reference LASer LIMit I1 Cc DEVICE DEPENDENT FRONT PANEL The LASer LIMit 11 query returns the value of the LASER current limit for the 100 mA range on the LDC 3714C or the 2000 mA range on the LDC 3744C Not applicable for LDC 3724C Notes The current limit is valid for all modes of Laser operation Examples LA
205. y be used via the front panel MOD EXTERNAL connector Follow the instructions below in the sequence presented Set Up the Controller Set the LDC 3700C in Constant Current low bandwidth mode by selecting I in the LASER MODE section of the front panel Do this by toggling the SELECT push button until the I indicator is illuminated Repeatedly pressing the LASER MODE SELECT switch cycles through the current I light power P or high bandwidth current law control modes LASER MODE SELECT lugw IL OUTPUT uus LDC 3700C Series Lightwave 04_09 OPERATIONS Operating from the Front Panel Set the Range Next in the RANGE section set the laser controller s current source range by selecting the 200 mA range indicated by the accompanying LED You will need to press the SELECT push button twice to change the range It must be pressed twice quickly within less than 1 second to switch between modes and the LASER output must be off LASER MODE ON indicator unlit in order to change ranges PRESS TWICE Select the Laser Display Configure the display so that it reads in mA by selecting I in the LASER DISPLAY section of the front panel directly underneath the LASER display The enunciators next to the display will indicate the display mode mA illuminates when I is pressed The LASER DISPLAY switch section is also used to select the lpp photodiode cur

LDC-3700C Series Laser Diode Controllers

Contents

Download Pdf Manuals

Related Search

Related Contents