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User`s Guide - Newport Corporation

1. Error Code Explanation E 123 Exponent too large in numeric data E 124 Too many digits in numeric data E 128 Numeric data not allowed E 130 General suffix error E 131 Invalid suffix received E 134 Suffix too long E 100 General command parsing error E 101 Invalid character E 102 Syntax error E 103 Invalid separator E 104 Data type error E 108 Invalid parameter for command E 109 Command is missing a parameter E 110 Command header error E 111 Command header separator error E 112 Program mnemonic is too long E 113 Undefined command header E 114 Header suffix is out of range E 115 Unexpected number of parameters received E 120 General numeric data error E 121 Invalid character included in numeric data E 123 Exponent too large in numeric data E 124 Too many digits in numeric data E 128 Numeric data not allowed E 130 General suffix error E 131 Invalid suffix received E 134 Suffix too long E 138 Suffix not allowed E 140 General character data error E 141 Invalid character data received E 144 Character data too long E 148 Character data not allowed E 150 General string data error September 2014 77 LDC 3736 Quantum Cascade Laser Controller Error Code Explanation E 151 Invalid st
2. Error Code Explanation E 260 Executable expression error E 261 Math error in executable expression E 270 General executable macro error E 271 A macro syntax error has occurred during execution E 272 A macro error has occurred during execution E 273 Illegal macro label E 274 Executable macro parameter error E 275 Macro definition is too long E 276 A macro recursion error has occurred E 277 Attempted macro redefinition is not allowed E 278 Macro header was not found E 280 A general program error has occurred E 281 Cannot create program E 282 Illegal program name E 283 Illegal variable name E 284 Program is currently running E 285 A program syntax error has occurred E 286 A program runtime error has occurred E 290 A memory use error has occurred E 291 The executable has run out of memory E 292 The referenced name does not exist E 293 The referenced name already exists E 294 An incompatible data type error has occurred E 300 General device specific error E 310 General device specific system error E 311 General device specific memory error E 312 System memory has been lost E 313 Calibration memory has been lost E 314 Save Recall memory has been lost E 315 Configuration memory has been lost E 320 A storage fault has occurred E 321 The device is out of memory E 330 The device self test has failed E 340 The calibration procedure has failed E 341 The calibration data entered is inv
3. 2 Measure and record the exact resistance of a 2 Q 150 W resistor A 4 point probe resistance measurement is recommended Connect the 2 Q 150 W resistor across the TEC output terminals of the LDC 3726 3746 pins 1 and 3 of the 15 pin connector or the LDC 3736 37620 pins 9 10 21 22 and 12 13 24 25 of the 25 pin connector Navigate to the Ite Cal selection in the Calibration submenu of TEC parameter menu tree Select the ITE calibration mode by pressing the SET button while the Ite Cal selection is displayed Then press the TEC button to start the calibration procedure Calculate the actual current output by using Ohm s Law I V R Where V is the accurately measured voltage across the resistor with a precision multimeter and R is the accurately measured load resistance The first current should be approximately 1 or 2 A positive Turn the ADJUST knob until the display shows the value of the ITE measurement as calculated from step 4 Then press the TEC button The instrument will apply a second current approximately negative 1 or 2 A after a short time Repeat step 5 for the newly calculated current at this setpoint Wait for the 7 segment display to exit the calibration mode Once the self calibration is completed the calibration constants will be stored to the non volatile memory and the display will return to its previous state TEC Voltage Measurement Calibration The following procedure calibrate
4. If the Hot Side heatsink is too small for the application it eventually becomes heat saturated wherein the heatsink can no longer dissipate the heat being generated When the heatsink becomes saturated the TEC current increases in an attempt to cool the load The additional current creates more heat that cannot be dissipated and subsequently more TEC current is applied This situation is referred to as thermal runaway and can cause a load and temperature controller to become damaged To help avoid damage caused by thermal runaway the LDC 3736 s temperature controller provides a high temperature limit setting When the load temperature exceeds the temperature limit the LDC 3736 s temperature controller turns off the TEC current and laser current source output if the LD TEC error link is enabled and generates an error on the TEC display September 2014 26 LDC 3736 Quantum Cascade Laser Controller Constant Temperature Mode Operation 1 Plug the LDC 3736 Instrument into an appropriate AC power source supplying the correct mains voltage and frequency for your instrument refer to the rear panel for the correct ratings Tum on the LDC 3736 The TEC output will be disabled at power up and the unit will automatically configure its parameters to the state which existed when the power was last shut off Press the SELECT soft button in the TEC MODE section of the front panel until the TEMP LED is selected Press the TEC soft button in the
5. NSTrument NSELect lt nrf gt Reports the possible instrument type settings available Selects between Laser current source or TE controller instrument operating modes NSTrument NSELect Reports currently selected instrument operating mode NSTrument SELect lt string gt Selects between Laser current source or TE controller instrument operating modes NSTrument SELect Reports currently selected instrument operating mode MEASure SCALar F RESistance Report TE sensor resistance measurement Report LDI or ITE depending on currently MEASure SCALar CURRent 1 selected instrument mode MEASure SCALar CURRent2 Report photodiode current measurement MEASure SCALar POWer Report photodiode power measurement MEASure SCALar TEMPerature Report temperature measurement September 2014 46 LDC 3736 Quantum Cascade Laser Controller MEASure SCALar VOLTage Report LDV or VTE depending on the currently selected instrument mode MEASure SENSor Report the currently selected sensor measurement OUTPut 1 STATe lt bool gt Set output state of currently selected instrument OUTPut 1 STATe Reports output state of currently selected instrument mode OUTPut2 STATe lt bool gt Enable or disable external fan control OUTPut2 STATe Report external fan output state
6. September 2014 56 LDC 3736 Quantum Cascade Laser Controller CAL Culate TRANsform TEMPerature SHHart A lt nrf gt CAL Culate TRANsform TEMPerature SHHart A Description Sets Returns Steinhart Hart parameter C1 for a thermistor temperature transducer Parameters C1 9 9999 to 9 9999 representing the first parameter of the Steinhart Hart equation multiplied by 10 Notes The Steinhart Hart equation C1 C2 n R C3 In3 R Where R is the resistance at temperature T Reset Value 1 125 CALCulate TRANsform TEMPerature SHHart B lt nrf gt CALCulate TRANsform TEMPerature SHHart B Description Sets Returns Steinhart Hart parameter C2 for a thermistor temperature transducer Parameters C2 9 9999 to 9 9999 representing the second parameter of the Steinhart Hart equation multiplied by 10 Notes The Steinhart Hart equation C1 C2 In R C3 In3 R Where R is the resistance at temperature T Reset Value 2 347 CALCulate TRANsform TEMPerature SHHart C lt nrf gt CALCulate TRANsform TEMPerature SHHart C Description Sets Returns Steinhart Hart parameters C3 for a thermistor temperature transducer Parameters C3 9 9999 to 9 9999 representing the third parameter of the Steinhart Hart equation multiplied by 107 Notes The Steinhart Hart equation i C1 C2 In R C3 In R Where R is the resistance at temperature T Reset Value 0 855 CALibrate CURR100UA STARt CALibrate CURR100UA DATA lt nrf gt
7. An enabled output is indicated by an illumined LED above the ON button left A disabled output is indicated by an unlit LED above the ON button left e TEMPERATURE Sets the LDC 3736 temperature controller to maintain a constant temperature e SENSOR Controls the LDC 3736 temperature controller to a constant sensor value e TE CURRENT Sets the LDC 3736 temperature controller to output a constant current e HEAT Illuminated when negative current is flowing e COOL Illuminated when positive current is flowing e TEMP LIMIT Illuminated if the LDC 3736 has exceeded the user defined temperature limits e CURRENT LIMIT Left Illuminated if the LDC 3736 temperature controller has reached the user defined current limit Laser Current Source Setup LASER Button Uses a menu system for temperature controller setup functions including limits and modulation state The SET right button selects each menu item and a second SET right press allows the user to adjust each parameter The ADJUST knob can be used to cycle through and select or modify the following parameters M warnine For the best laser diode protection it is recommend to set the current limit slightly above your expected operating current this should be below the maximum current as stated on the laser diode datasheet In addition the voltage limit should be set to just above the typical operating voltage this should also be below the maximum voltage as stat
8. C2 and C3 into the temperature controller If the exact temperature is not crucial within 1 5 C and you are using a 10 kQ thermistor use the default constants provided by the LDC 3706 Series instrument Thermistor resistance changes with temperature The LDC 3736 supplies a constant current either 10 yA or 100 pA through the thermistor so that a temperature change results in a voltage change across the thermistor This voltage change is sensed by the instrument and fed back to the control loop The supply current selection depends on the thermistor operating temperature range and the required temperature resolution A general rule of thumb for a 100 kO thermistor is to use the 10 pA range for temperatures between 30 C and 30 C and for 10 kQ thermistor the 100 LA range for temperatures between 10 C to 70 C Select the thermistor sense current of 10 pA or 100 pA in the front panel TEC parameter menu Using 10 pA as the thermistor current allows you to use a maximum thermistor resistance of 450 kQ The 100 pA setting allows a 45 kQ maximum The LDC 3736 instrument has the ability to select the temperature sensor current range based on the resistance of the measurement and will automatically switch between the 10 A and 100 UA modes Thermistor auto range can be selected under the SENSOR submenu within the TEC parameters menu To ensure proper thermistor current and thermistor selection certain principles must be considered e To en
9. Description Begins Takes data for the 100 pA thermistor calibration procedure Parameters DATA a number representing the measured current in Amps CALibrate CURR10UA STARt CALibrate CURR10UA DATA lt nrf gt Description Begins Takes data for the 10 pA thermistor calibration procedure Parameters DATA a number representing the measured current in Amps September 2014 57 LDC 3736 Quantum Cascade Laser Controller CALibrate CURRent STARt CALibrate CURRent DATA lt nrf gt Description Begins Takes data for the laser current calibration procedure if the laser diode mode is selected or for the TEC current output calibration procedure if the TEC controller mode is selected see the INSTrument SELect command Parameters DATA a number representing the measured current in Amps CALibrate DATE lt nrf gt lt nrf gt lt nrf gt CALibrate DATE Description Sets Reports the calibration date information for the instrument Parameters Month Day Year the month day and year that represent the last calibration date CALibrate MDI STARt CALibrate MDI DATA lt nrf gt Description Begins Takes data for the monitor photodiode current calibration procedure Parameters DATA a number representing the measured current in Amps CALibrate PDI STARt CALibrate PDI DATA lt nrf gt Description Begins Takes data for the monitor photodiode current calibration procedure Parameters DATA a number representing the meas
10. Execution Error means a parameter was evaluated to be outside the legal input range or capability Command Error means a command could not be interpreted by the parser Unused and always reports 0 Bit 7 Power On indicates that an off to on transition has occurred in the power supply CLS will clear this register oak Ga KM Examples ESR A response of 32 means a command error has occurred IDN Instrument Identification Description Requests the instrument to identify itself Parameters None Notes Returns a string of instrument identification information The string contains a comma separated list of manufacturer model number serial number and firmware revision Examples IDN Responds with ILX Lightwave LDC 3706 37061111 1 00 1 00 September 2014 51 LDC 3736 Quantum Cascade Laser Controller OPC Operation Complete Description Parameters Notes Examples OPC Sets the operation complete bit bit 0 in the standard event status register when all pending overlapped commands have been completed None This command does not hold off subsequent operations You can determine when the overlapped commands have completed either by polling the standard event status register ESR or by setting up the status system such that a service request is asserted when bit 0 is set in the standard event status register OUTPUT ON OPC Will set bit O in the standard event status register when the output
11. KNOB to the desired value The user can display measured voltage current or temperature or the sensor setpoint on the TEC side left display by pressing the LEFT left and RIGHT left display buttons in constant sensor mode The user can display measured voltage current or sensor value or the temperature setpoint on the TEC side display LEFT by pressing the LEFT left and RIGHT left display buttons in constant temperature mode Enable the TEC output of the LDC 3736 by pressing the ON soft button left in the TEC MODE section of the front panel This button has a toggling action so pressing this button once more will disable the TEC output September 2014 30 LDC 3736 Quantum Cascade Laser Controller Chapter 2 Remote Operation This chapter is an overview of the remote operation of the LDC 3736 Quantum Cascade Laser Controller Y Fundamentals of Remote Operation Command Syntax Test and measurement equipment with remote operation capability will generally communicate through either GPIB or USB interfaces GPIB General Purpose Interface Bus is the common name for ANSIIEEE Standard 488 2 1987 an industry standard for interconnecting test instruments in a system USB Universal Serial Bus is the common serial communication protocol used by most computers for relatively fast communication Everything that can be done from the front panel can also be done remotely and in some cases with more flexibility The following sections
12. c Notes The Callendar Van Dusen equation Rr Ro 1 AT BT CT3 T 100 T lt 0 C Rr Roll AT BT T 20 C Where Rr is the resistance at temperature T Reset Value 3 908 CALCulate TRANsform TEMPerature CVDusen B lt nrf gt CALCulate TRANsform TEMPerature CVDusen B Description Sets Reports coefficient B CVD B for the Callender Van Dusen RTD resistance to temperature equation Parameters CVD B 9 999 to 9 999 representing the second coefficient of the Callendar Van Dusen equation multiplied by 107 oc Notes The Callendar Van Dusen equation Rr Ball AT BT CT T 100 T lt 0 C Rr Ro 1 AT BT T 20 C Where R is the resistance at temperature T Reset Value 5 775 CALCulate TRANsform TEMPerature CVDusen C lt nrf gt CALCulate TRANsform TEMPerature CVDusen C Description Sets Reports coefficient C CVD C for the Callender Van Dusen RTD resistance to temperature equation Parameters CVD C 9 999 to 9 999 representing the third coefficient of the Callendar Van Dusen equation multiplied by 102 oc Notes The Callendar Van Dusen equation Rr Ro 1 AT BT CT T 100 T lt 0 C Rr Roll AT BT T 20 C Where R is the resistance at temperature T Reset Value 4 183 September 2014 55 LDC 3736 Quantum Cascade Laser Controller CALCulate TRANsform TEMPerature CVDusen R lt nrf gt CALCulate TRANsform TEMPerature CVDusen R Description Sets Reports co
13. 0 1 ON OFF OFF INSTrument CATalog Description Response Reports the possible instrument mode selections for the LDC 3706 Responds with the string LAS TEC the two possible operating modes for the LDC 3706 INSTrument NSELect lt nrf gt INSTrument NSELect Description Parameters September 2014 Sets Reports the instrument operating mode instrument mode 1 or 2 1 for laser driver mode and 2 for TEC controller mode 62 LDC 3736 Quantum Cascade Laser Controller INSTrument SELect lt string gt INSTrument SELect Description Sets Reports the instrument operating mode Parameters instrument mode LAS or TEC LAS for laser driver mode and TEC for TEC controller mode MEASure SCALar F RESistance Description Reports the TE sensor resistance in Ohms MEASure SCALar CURRent 1 Description Reports the laser diode output current in Amps in laser driver mode or the TEC controller output current in Amps in TEC controller mode MEASure SCALar CURRent2 Description Reports photodiode current measurement in milliamps MEASure SCALar POWer Description Reports photodiode power measurement in milliwatts MEASure SCALar TEMPerature Description Reports TE temperature measurement in C MEASure SCALar VOLTage Description Reports the laser diode output voltage in Volts in laser driver mode or the TEC controller output voltage in Volts in TEC contro
14. 1 C is tolerable no calibration of C1 or C2 is required just set C1 0 C2 1 If a maximum absolute error of 0 5 C is tolerable the one point calibration of C1 may be used see page C 5 If a greater accuracy is desired the two point method of determining C1 and C2 should be used see page C 6 Note however the absolute error associated with the constant C2 may vary over different temperature ranges One Point Calibration Method This procedure will work for any linear IC temperature sensor The accuracy of this procedure depends on the accuracy of the known temperature externally measured It is used to determine the zero offset of the device and it assumes that the gain offset slope is known and is correct 1 Allow the LDC 3736 to warm up for at least one hour Set the sensor to the desired sensor type and RECALL the constants for the particular device to be calibrated 2 Select the C1 parameter Read and record the value of C1 3 Place the sensor at an accurately known and stable temperature Ta Connect the sensor to pins 14 and 15 of the LDC 3736 25 pin connector Set the LDC 3736 for normal constant temperature T mode operation Allow the LDC 3736 to stabilize at the known temperature Ta and read the displayed temperature Td 4 Determine the new value of the offset offset new from the formula Offset New Previous Offset Value Ta Td and replace the previous offset value with the newly calculated
15. LOW Description Sets reports lower TEC current limit Parameters lower limit 8 00 0 00 lower current limit in Amps Reset Value 8 00 September 2014 64 LDC 3736 Quantum Cascade Laser Controller SOURce 1 CURRent LIMit AMPLitude lt nrf gt SOURce 1 CURRent LIMit AMPLitude Description Sets reports laser driver current limit Parameters limit 0 00 4 040 current limit in Amps Reset Value 0 500 Amp 500 mA SOURce 1 CURRent RANGe lt nrf gt SOURce 1 CURRent RANGe Description Sets reports laser driver current range Parameters range 1 2 or 4 1 for 1 Amp range 2 for 2 Amp range and 4 for 4 Amp range SOURce 1 CURRent LEVel IMMediate lt nrf gt SOURce 1 CURRent LEVel IMMediate Description Sets reports laser driver current setpoint in laser driver mode or TEC current setpoint in TEC controller mode Parameters setpoint 8 000 to 8 000 current setpoint in Amps SOURce 1 FUNCtion MODE lt string gt SOURce 1 FUNCtion MODE Description Sets reports laser driver operating mode in laser driver mode or TEC operating mode in TEC controller mode Parameters mode string representing operation mode see notes Notes Acceptable strings for first parameter POWer laser driver mode only CURRent TEMPerature TEC controller mode only RESistance TEC controller mode only SOURce 1 POWer LIMit lt nrf gt SOURCce 1 POWer LIMit Description Sets reports las
16. ORDERING INFORMATION Range 0 to 600 pA Resolution Display 0 001 pA LDC 3736 Quantum Cascade Laser Controller Accuracy 0 18 pA LDM 487201 Quantum Cascade Laser Mount C Mount RTD Sensor Resistance l LDM 487202 Quantum Cascade Laser Mount Alpes COC er Setting Oto 15002 CC 305S Current Source Laser Diode Mount Interconnect Cable Resolution Display 0010 CC 306S Current Source Unterminated Interconnect Cable Accuracy k 0 80 CC 594H TE Controller Unterminated Interconnect Cable 2 5 mA Bias Setting CC 595S TE Controller Laser Diode Mount Interconnect Cable i Range 0t02000 CC 596H TE Controller High Power Laser Diode Mount Interconnect Cable e yaa je ps ee LabVIEW Instrument Driver User Sensor Calibration Thermistor Steinhart Hart 3 constants IC Sensors Slope Offset RTD R A B C September 2014 5 LDC 3736 Quantum Cascade Laser Controller September 2014 6 LDC 3736 Quantum Cascade Laser Controller Chapter 2 General Operation This chapter is an overview of the operation of the LDC 3736 Quantum Cascade Laser Controller 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 Constant Temperature Mode ILX recommends that you review the contents of this chapter
17. PARAMETER section of the front panel to adjust the applicable limits sensor type sensor calibration constants and external fan control Adjust the temperature setpoint by enabling the ADJUST KNOB for TEC parameter adjustment by pressing the TEC button in the ADJUST section of the front panel upper right Use the ADJUST KNOB to change the setpoint temperature to the desired value by rotating clockwise to increase the parameter and counter clockwise to decrease The new parameter is now stored in non volatile memory The user can display measured voltage current or sensor value or the temperature setpoint on the TEC side display LEFT and cycle through the available display parameters by pressing the LEFT left and RIGHT left display buttons Enable the TEC output of the LDC 3736 by pressing the ON soft button left in the TEC MODE section of the front panel This button has a toggling action so pressing this button once more will disable the TEC output September 2014 27 LDC 3736 Quantum Cascade Laser Controller Constant Sensor Mode Operation 1 Plug the LDC 3736 Quantum Cascade Laser Controller into an AC power source supplying the correct mains voltage and frequency for your instrument refer to the rear panel for the correct ratings Tum on the LDC 3736 The TEC output will be disabled at power up and the unit will automatically configure its parameters to the state which existed when the power was last shut off Press the SE
18. Recall Button descriptions in the Front Panel Operation section of this chapter for more information Firmware Upgradeability The firmware on the LDC 3736 instrument can be reinstalled or upgraded via USB Contact ILX Lightwave technical support for information on upgrading the software of the LDC 3736 instrument GPIB Communication The IEEE 488 GPIB interface connector is located on the rear panel directly above the power input module See Figure 1 2 on page 2 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 GPIB 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 As good practice the number of GPIB cables connected to one instrument should be limited to less than 6 September 2014 8 LDC 3736 Quantum Cascade Laser Controller USB Communication The USB connector is located on the back rear panel next to 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 with the instrument using USB please i
19. SENSor lt string gt Set the temperature sensor type See Command Reference below for more information Report the currently selected temperature sensor SENSor type See Command Reference below for more information SOURce 1 AM STATE lt integer gt Enable or disable LDI modulation SOURce 1 AM STATE Report currently selected LDI modulation state SOURce 1 CURRent LIMit HIGH lt nrf gt Set upper TEC current limit SOURce 1 CURRent LIMit HIGH Report upper TEC current limit SOURce 1 CURRent LIMit LOW lt nrf gt Set lower TEC current limit SOURce 1 CURRent LIMit LOW Report lower TEC current limit SOURce 1 CURRent LIMit AMPLitude lt nrf gt Set laser current limit SOURce 1 CURRent LIMit AMPLitude 7 Report laser current limit SOURce 1 CURRent RANGe lt nrf gt Set range of laser current source Report currently selected laser current source SOURce 1 CURRent RANGe range Set control setpoint for LDI or ITE depending SOURce 1 CURRent LEVel L IMMediate lt nrf gt on the currently selected instrument mode Report control setpoint for LDI or ITE SOURce 1 CURRent LEVel IMMediate depending on the currently selected instrument mode Set the operating mode for the currently SOURce 1 FUNCt ion MODE lt string gt selected instrument mode See Command Reference below for more information Report the op
20. explain the fundamentals of operating the LDC 3736 Quantum Cascade Laser Controller remotely through either the GPIB or USB computer interface GPIB Address The talk and listen addresses on the LDC 3736 are identical This GPIB address is read locally by pressing the LOCAL button in the COMM section of the front panel until the GPIB Address is displayed on one of the dot matrix displays The instrument comes from the factory configured with the GPIB address set to 1 You can change the LDC 3736 s GPIB address locally via the front panel A procedure for changing the address can be found in the section changing the GPIB Address Basic GPIB Concepts The information in this section is normally not necessary to successfully operate the LDC 3736 instrument through its GPIB interface because the host computer s GPIB controller usually handles the details However it is a useful introduction to 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 or un addressing de
21. laser diode voltage readings and the monitor diode current reading See chapter 5 for more details STORE Button Stores instrument parameters for control mode setpoints limits sensor type sensor calibration constants and PID values for bins numbered 1 10 RECALL Button Recalls instrument parameters for control mode setpoints limits sensor type sensor calibration constants and PID values for bins numbered 1 10 Recall bin O will reset all parameters to the factory defaults Non volatile memory is used for saving the instrument parameters When a store operation is performed all of the current instrument parameters are stored to a bin number 1 10 When that bin number is recalled the instrument configuration is recalled to the stored values To enter the STORE RECALL mode press either the STORE or RECALL button which will display the current bin number in the bottom of the screen The current bin number will be flashing and the ADJUST knob can be used to select a new bin The store or recall operation is performed when the SET button is pressed If the SET button isn t pressed after three seconds the LDC 3736 instrument will time out and the new bin number will not be stored or recalled Modulation State The Modulation State parameter allows the user to select whether the Laser Modulation Analog input is enabled or not For best results when not modulating the laser through the BNC inp
22. lower limit SOURce 1 RESistance PROTection Set the TE controller resistance upper limit HIGH lt nrf gt SOURce 1 RESistance PROTection l Report the TE controller resistance upper limit L HIGH SOURce 1 RESistance SPOint lt nrf gt Set the TE controller resistance setpoint SOURce 1 RESistance SPOint Report the TE controller resistance setpoint Set the TEC resistance tolerance See status SOURce RESistance TOLerance lt nrf gt section out of tolerance bit in condition reg SOURce RESistance TOLerance Report the TEC resistance tolerance setting l Enable or disable TE controller analog SOURce TEMPerature AM STATE lt integer gt temperature modulation SOURce 1 TEMPerature AM STATE Report analog temperature modulation state SOURce 1 TEMPerature LCONstants Set the D term for the TEC controller PID DERivative lt nrf gt control loop SOURce 1 TEMPerature LCONstants Report the D term for the TEC controller PID DERivative control loop SOURce 1 TEMPerature LCONstants Set the I term for the TEC controller PID NTegral lt nrf gt control loop SOURce 1 TEMPerature LCONstants Report the I term for the TEC controller PID NTegral control loop SOURce TEMPerature LCONstants Set the P term for the TEC controller PID GAIN lt nrf gt control loop SOURce TEMPerature LCONstants Report the P term for the TEC controller PID GAIN control loop SOUR
23. mW 0 00 20000 0 0 00 20000 0 0 00 20000 0 Resolution 0 imW 0 1mW 0 1mW Forward Voltage Range 0 000 18 000V 0 000 18 000V 0 000 18 000V Resolution imV ImV 1mV Accuracy 2mV 2mV 2mV GENERAL CURRENT SOURCE NOTES UO Connectors 1 All values relate to a one hour warm up period TEC I O Female 25 pin D sub S GE Analog Input BNC 4 Measured electrically with a frequency range of 100Hz to 340kHz High Bandwidth 100Hz to 17kHz Low Bandwidth Remote Interface GPIB IEEE 488 1 USB 2 0 B Type 5 Maximum output current transient resulting from normal operational situations e g power on off current on off as well Power Requirements AC Input Selector 115 230 VAC accidental situations e g power line plug removal To protect the laser in all conditions it is recommended to set both the current 100 120 VAC 220 240 VAC 500W and voltage limit just above typical operating conditions 50 60 Hz 6 Maximum output current transient resulting from a 1000V power line transient spike Tested to ILX Technical Standard A E o o a LDC 00196 request ILX App Note 13 Size HxWxD F e E pad x 345 mm 7 Maximum monitor photodiode current drift over any 30 minute period Assumes zero drift in responsivity of photodiode K 8 50 modulation at mid scale output Higher bandwidth is possible with smaller modulation signal Bei e i a Va kg 9 Small signal specification is for typical 10 modulation depth Large signal specification assumes 50 modulation dep
24. make twisted pairs with several of the lines There are eight data input output lines three handshake lines and five interface management lines Eight data I O 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 DIO1 DIOS DIO2 DIO6 DIO3 DIO7 DIO4 DIO8 REN GND Twisted pair with DAV GND Twisted pair with NRFD GND Twisted pair with NDAC EOI DAV NRFD NDAC IFC SRQ ATN SHIELD GND Twisted pair with IFC GND Twisted pair with SRQ GND Twisted pair with ATN SIGNAL GROUND Figure 3 2 GPIB Connector 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 September 2014 33 LDC 3736 Quantum Cascade Laser Controller ATN 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 re
25. output connections of the LDC 3736 instruments are isolated from the chassis ground allowing either output terminal to be grounded If a terminal is grounded be 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 the instrument and devices will occur M warnine The Temperature Control output terminals of the LDC 3736 Quantum Cascade Laser Controller TE Module and TE Module should never be shorted together or loaded with less than 0 1 O Doing so may result in damage to the instrument Analog Modulation Input An isolated BNC connector is located on the front panel of the LDC 3736 instrument and provides the capability to modulate the output of the laser current source This connector can accept a signal from O to 10 V and a nominal input impedance of 1 kO The transfer function and bandwidth of this input is dependent on the mode of operation of the instrument For further details please consult the Specifications section of Chapter 1 This feature is useful in applications requiring modulation of the output current without using either GPIB or USB remote interfaces Analog Temperature Control Input An isolated BNC connector is lo
26. proportional to absolute temperature over its useful range 40 C to 100 C This nominal value can be expressed as V 10 mV K Where V is the nominal voltage produced by the LM335 and K is the temperature in Kelvin The LDC 3706 Series instruments use V to determine the nominal temperature T by the formula T V 10mV K 273 15 Where T is measured in C The temperature T which is displayed by the LDC 3736 instrument is first calibrated as follows T C1 C2 10 0 T Where C1 and C2 are the constants stored by the user in the LDC 3736 instrument for the LM335 When the LDC 3736 instrument is shipped from the factory the LM335 measurement system is calibrated but the sensor C1 and C2 is not Nominally C1 0 and C2 10 In that case the temperature accuracy is typically 1 C over the rated operating range With C1 and C2 calibrated also the temperature accuracy is typically 0 3 C over the rated operating range The temperature accuracy may be improved over a narrow temperature range by a two point calibration of C1 and C2 However the LM335 is not perfectly linear and even with C1 September 2014 90 LDC 3736 Quantum Cascade Laser Controller accurately known and C2 uncalibrated there is a non linear absolute temperature error associated with the device This non linearity caused error is typically 0 3 C with the error associated with C1 assumed to be zero If a maximum absolute error of
27. r Status Summary Service Request Enable Register SRE lt nrf gt SRE Examples SRE 16 Enables the service request enable register to generate a service request when a query generating message is available to read from the output queue SRE Service Request Enable Query Description Returns the enabled bits in the service request enable register Parameters None Notes The response is a value between 0 and 255 representing the bits of the standard event status enable register when expressed in base 2 binary format Examples SRE A response of 16 signifies that the message available summary bit is enabled September 2014 53 LDC 3736 Quantum Cascade Laser Controller STB Status Byte Query Description Returns the value of the status byte register Parameters None Notes The response is the sum of the enabled bits and must be a value between 0 and 255 Se ae e e q l 1 l e Status Byte Register SERVICE ka STB REQUEST 6 Beate GENERATION Le red T Condition Summary sous ai KA a e r d Service Request Enable Register SRE lt nrf gt SRE Examples STB A response of 129 specifies that the TEC event summary and the error available bits are set TST Self Test Description Performs an internal self test and then reports results Parameters None Notes Response 0 test completed with no errors Response 1 test completed with errors This is a synchronous com
28. the first command is completed before its execution begins See the Operation Complete Definition earlier in this chapter 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 has completed Some common commands are sequential the next command must wait until this command has completed The operation complete flag is set after the conditions outlined in the Operation Complete Definition have been satisfied The WAI common command is an example of a sequential command which forces the next command to wait until the no operation 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 0 of the Standard Event Status Register Commands which change the status of the instrument limits or change its mode 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 small September 2014 41 LDC 3736 Quantum Cascade La
29. transaction consists of a number of packets a packet contains a token indicating the type of data that the host is sending or requiring the data and in some cases an acknowledgement Each packet is preceded by a sync field and followed by an end of packet marker These transactions are used to provide four basic data transfer mechanisms including control interrupt bulk and isochronous types USBTMC stands for USB Test and Measurement Class USBTMC is a protocol built on top of USB that allows GPIB like communication with USB devices From the user s point of view the USB device behaves just like a GPIB device For example you can use VISA Write to send the IDN Query and use VISA Read to get the response The USBTMC protocol supports service request triggers and other GPIB specific operations USBTMC allows instrument manufacturers to upgrade the physical layer from GPIB to USB while maintaining software compatibility with existing software such as instrument drivers and any application that uses VISA September 2014 34 LDC 3736 Quantum Cascade Laser Controller Changing Between Local and Remote Operation Sending a command over the GPIB or USB bus automatically puts the instrument in Remote mode The Remote indicator identifies when the controller is in remote operation mode When the instrument is in Remote mode all front panel controls are disabled except for the Local button Pressing the Local button returns the instrument to Local c
30. tune process The screen will say Start Autotune lt SET gt While this is displayed press SET to begin the auto tune procedure When the LDC 3736 instrument successfully completes the auto tune the instrument will revert back to MANUAL PID mode and the calculated PID values will overwrite the current PID values in MANUAL mode If the auto tune process fails an error will be displayed on the screen For more information on the auto tune process see Appendix B Additional auto tune methods may be available in the future via a firmware upgrade for more information contact sales at 800 459 9459 sales ilxlightwave com September 2014 15 LDC 3736 Quantum Cascade Laser Controller There are limitations to the auto tune feature Any of the following will cause the auto tune algorithm to fail e Thermal systems requiring the proportional term to be less than 0 5 e Noisy temperature measurements e Reaching any output off enable condition such as temperature or voltage limits during the auto tune operation If the auto tune algorithm fails for a particular thermal system it may be necessary to modify the PID coefficients manually Temperature Control Mode SELECT Button Middle Selects constant temperature constant sensor and constant current mode The selected mode is indicated by an illuminated LED The output is disabled when the control mode is changed ON Button Left Enables and disables the temperature controller output
31. until the problem returns Then check the other instrument for address conflicts and proper GPIB function Read the error queue remotely SYST ERR The command syntax or command structure may be in error Read the status byte STB for possible device problems September 2014 73 LDC 3736 Quantum Cascade Laser Controller LASER CONTROLLER Power on but no current output Check the interlock pins on the LASER input connector on the instrument rear panel These pins must be shorted either directly or through a switch If an Open Circuit Error is shown on the display check the load connections and then try again Check the OUTPUT ON switch the corresponding LED should be lit Output current at limit cannot be If POWER mode is used check the monitor diode lowered feedback connections Try reversing the polarity of the monitor photodiode Check the photodiode bias adjustment in the LASER PARAMETER menu If in constant current 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 LASE
32. 0 pins 14 and 15 Enter the sensor calibration mode by navigating to the RTD2mACal selection in the Sensor Cal area of the Calibration submenu of TEC parameter menu tree Select the appropriate RTD calibration selection by pressing the SET button when the title for that calibration procedure is shown on the display then press the TEC button in order to enable the sensor current Turn the ADJUST knob until the display indicates the same resistance you recorded for the 60 O resistor Press the TEC button Connect the 1200 O resistor to the sensor pins Turn the ADJUST knob until the display indicates the same resistance you recorded for the 240 O resistor Press the TEC button Wait for the 7 segment display to exit the calibration mode and reflect the entered sensor resistance setpoint Once the calibration is completed the calibration constants will be stored to the non volatile memory and the display will return to its previous state September 2014 84 LDC 3736 Quantum Cascade Laser Controller ITE Current Calibration The following procedure calibrates the ITE constant current source for both polarities of current During this procedure the ITE current is driven to two pre determined values 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 3736 Quantum Cascade Laser Controller then automatically calibrates the TEC current source and limits 1
33. 1 MEASure MEDium CURRent 1 MEASure HIGH VOLTage MEASure CURRent2 MEASure CURRent2 CURRent SETPoint CURRent MEASure SENSor VOLTage SENSor CURRent THERM10UA SENSor CURRent THERM100UA SENSor CURRent RTD1MA SENSor CURRent RTD2_5MA SENSor RESistance COUNts ALL 59 Begins Takes data for the TE ICV sensor voltage calibration procedure Sets Reports calibration constants for various instrument measurements and sepoints value to set string representing what measurement or setpoint to be set see notes for acceptable inputs LDC 3736 Quantum Cascade Laser Controller CALibrate VALues ERASe lt string gt Description Parameters Notes September 2014 Resets calibration constants for various instrument measurements and sepoints to default settings value to reset string representing what measurement or setpoint to be reset see notes for acceptable inputs Acceptable strings for first parameter CURRent 1 SETPoint LOW BYPass CURRent 1 SETPoint LOW CURRent 1 SETPoint MEDium BYPass CURRent 1 SETPoint MEDium CURRent 1 SETPoint HIGH BY Pass CURRent 1 SETPoint HIGH CURRent 1 LIMitLOW CURRent 1 LIMit MEDium CURRent 1 LIMit HIGH VOLTage LIMit POWer LIMit CURRent 1 MEASure LOW CURRent 1 MEASure MEDium CURRent 1 MEASure HIGH VOLTage MEASure CURRent2 MEASure CURRent2 CURRent SETPoint CURRent MEASure SENSor VOLTage
34. 5 General Operating Procedures The discussion below presents guidelines for operation as well as some common operating procedures Remote operations are discussed in the next chapter M warnine The output terminals of the LDC 3736 instrument should never be shorted together or loaded with less than 0 1 O Doing so may result in damage to the instrument Warm Up and Environmental Considerations To achieve the rated accuracy allow the LDC 3736 instrument to warm up for at least one hour before use Always operate the controller within the environmental limits specified in the Specifications section of Chapter 1 The best accuracy is achieved near the calibration temperature of 23 C Operating the Laser Current Source from the Front Panel This section describes fundamentals of operation for your LDC 3736 Quantum Cascade Laser Controller Laser Current Source in two operating modes Constant Current I and Constant Power P The current mode of operation is indicated by a lit LED next to the mode of operation in use in the Laser Mode section of the front panel The mode of operation may be adjusted using the Select right button in this section of the front panel Operating a Laser in Constant Current Current Mode 1 Plug the LDC 3736 into an appropriate AC power source supplying the correct mains voltage and frequency for your instrument refer to the rear panel for the correct ratings 2 Turnon the LDC 3736 The laser output will
35. 5 voltage output ae a 5 to 14 mV K SEN IC I Semiconductor IC Sensor AD 590 current output 1 pA K Bandwidth i 5Hz RTD Sensor Platinum 10002 10000 2 wire External Fan Control Output Output Voltage Range Oto 12V Thermistor Sensor Resistance Maximum Current 600 mA a Bias Sahing TEMPERATURE CONTROL NOTES Sa j ta 1 Al values are speciied for an ambient temperature of 245 C ater a 1 hour warm up unless otherwise specified le A 2 Software imits of Actual onthe load and TEC module used Accuracy N 1800 3 oeiras ai ee This figure does not 100 pA Bias Setting include the sensor calibrabon uncertaintes Thermistor accuracy figures are quoted for a typical 10 k thermistor and 100 pA current gating fr SPC to STC Range l O to 45 M amp Temperature stability measurements made in a stable ambient environment 0 5 C wih a 10 kf thermistor on the 100 Resolution Display 0 001 KQ WA Setting after a 2 hour warm up period Stabilty is defined as Tmax Tmin 2 over ihe measurement pare Acc U E 4182 5 Measured over the full DC current range into 1 2 load Maximum resoluson operating in L resolubon w IC V Sensor Voltage posses solares saindo porem rd mapeadas gi Tala Bias Ep 7 Measured at the output connector Users may enter in cable resistance to provide an accurate voltage measurement at ange o the load Sea GG eee N non linear parel tunction which over the modulation IC I Sensor Current bes 2 Nominal Bias 5t015V
36. B 2 0 and USB 3 0 The 3736 is designed to conform to the USB 2 0 standard and USBTMC 488 substandard USB cables use 4 lines Power Ground and a twisted pair differential data lines The USB connectors are designed so that power and ground are applied before the signal lines are connected When the host powers up it performs the enumeration process by polling each of the Slave devices in turn using the reserved address 0 assigning each one a unique address and finding out from each device what its speed is and what type of data transfer it wishes to perform The enumeration process also takes place whenever a device is plugged into an active network The design of the connectors the process of enumeration the host software and the device firmware allows devices to be described as Plug and Play When the USB device is enumerated and gets an address from the host it presents the host with information about itself in the form of a series of descriptors The device descriptor tells the host the vendor and the product ID The configuration descriptors offer a power consumption value and a number of interface descriptors Each of these interface descriptors define a number of endpoints which are the sources and destinations for data transfers The endpoint descriptors provide the following details transfer type bulk interrupt or isochronous direction packet sizes bandwidth requirement and repeat interval In USB communication a typical
37. Conductor hot surface Terminal Frame or chassis terminal E Visible and or Caution refer Earth ground PM 1 O Alternating current invisible laser A to manual Terminal radiation Warranty ILX Lightwave Corporation warrants this instrument to be free from defects in material and workmanship for a period of one year from date of shipment During the warranty period ILX will repair or replace the unit at our option without charge Limitations This warranty does not apply to fuses lamps defects caused by abuse modifications or to use of the product for 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 September 2014 vii LDC 3736 Quantum Cascade Laser Controller Returning an Instrument If an instrument is to be shipped to ILX Lightwave for repair or service be sure to Obtain a Return Merchandise Authorization number RMA from ILX Customer Service 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 Attach the an
38. DEE II I tt Nao 1 RA A II 1 11 1 II H SERVICE Hi i RUES le EEI i GENERATION c 1 l LOGCAL OR N l Sia gt 1 i 1 K DD 1 l Service Request Enable Register 1 om K i 1 m L WEBEN ERROR QUEUE LOGICAL OR LASER Event Status Register INST LAS EVEnt h3 fz hn po Limit ppagg HD f Ju fis fiz LASER Event Status Enable Register INST LAS ENABle EVEnt lt nrf gt INST LAS ENABle EVEnt U TEC Condition Status Register d INST TEC CONDition JA i o 9 fa DD T HDH LOGICAL OR 1 SMBRE PPE PEELE TEC Condition Status Enable R INST TEC ENABle CONDition INST TEC ENABle CONDition INST TEC EVEnt fos Ta H H I TEC Event Status Register H H 1 DDR bim Hl vw TEC Event Status Enable Register Rs INST TEC ENABle EVEnt lt nrf gt INST TEC ENABle EVEnt Figure 3 5 Status Reporting Scheme September 2014 40 LDC 3736 Quantum Cascade Laser Controller 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 the first is being executed or if it must wait until
39. LECT soft button in the TEC MODE section of the front panel until the SENSOR LED is selected Press the TEC button in the PARAMETER section of the front panel to enable the menu structure and adjust the applicable limits sensor type sensor calibration constants and external fan control Use the SET button to select the parameter you wish to adjust and then use the ADJUST KNOB to change the parameter to the desired value Clockwise rotation will increase the parameter and counter clockwise rotation will decrease the parameter Allow the parameter adjustment to time out three seconds or press the SET button to save the new parameter in non volatile memory Adjust the sensor value setpoint by enabling the TEC adjustment mode by pressing the TEC button in the ADJUST section of the front panel and rotate the ADJUST KNOB to the desired value The user can display measured voltage current or temperature or the sensor setpoint on the TEC side left display by pressing the LEFT left and RIGHT left display buttons Enable the TEC output of the LDC 3706 Series instrument by pressing the ON soft button left in the TEC MODE section of the front panel This button has a toggling action so pressing this button once more will disable the TEC output September 2014 28 LDC 3736 Quantum Cascade Laser Controller Constant Current Mode Operation 1 Plug the LDC 3736 instrument into an AC power source supplying the correct mains voltage and frequency
40. Measurement Calibration eee e 85 Laser Driver Current Calbraton a aa aaarar ente anaaaananarenrananaaaaaa 86 Laser Voltage Measurement Calibration eeseser resser reer erenn 86 Photodiode Current Calibration sss eee eee 87 Appendix A AD590 and LM335 Sensor Calibration sse eee eee 89 E EE 89 LISO SINS TEE 90 One Point Calibration Method sese 91 Two Point Calibration Method 92 Appendix B Auto Tune Method 93 September 2014 iii LDC 3736 Quantum Cascade Laser Controller List of Figures Figure 1 1 LDG 3 736 Front Panel EE 2 Figure 1 2 LDG 3736 Rear Panel deser dene cesta tide bedi cen eee eet 2 Figure 2 1 Laser Diode Connection Configurations eee eee 12 Figure 2 2 Front Panel Display sais geesde Doda E Sand feia a dE Eege deed Eege 13 Figure 2 3a The Setpoint Current eareea near aa dg shred 18 Figure 2 3b The Measured Current ee sese ereer nenen nenen ennenen 18 Figure 2 4 Example Thermistor Resistance vs Temperature eee eee eee 24 Figure 3 1 GPIB Cable Connection er PEENE aAA E aerea near A ri 32 Figure EI ee 33 Figure 3 4 Common Command Diagrams sss sese eee eee eee 39 Figure 3 5 Status Reporting Scheme rear ceara a nnn 40 Figure A 1 Non Linearity Graph ias ese quesssta EENS ENEE NEEN 90 Figure B 1 Ki Te Nee 93 September 2014 iv LDC 3736 Quantum Cascade Laser Controller Safety and Warranty Inform
41. R ADJUST indicator the indicator must be lit for any LASER adjustments to be made Check the LIMIT parameter for the output range in use and that it is set above 0 mA Power Mode operation has high output Check the PD BIAS setting If it is set too low the power current but little or no power is control mode may act as an open feedback loop If in doubt measured set the PD BIAS to mid range 2 5 V Ensure that the current limit is set correctly according to laser manufacturer s datasheet Output exceeds Power Limit The Power Limit is not a hardware limit It only serves as a warning that the power measurement has exceeded the limit set point Ensure that the current limit is set correctly according to laser manufacturer s datasheet Open Circuit Error occurs during Check load connections Check that measuring meter does calibration 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 The LDC 3736 has an adjustable laser compliance voltage error E505 prevents output from Check to see if the LASER voltage limit setting is too low reaching desired value see Chapter 2 Check laser connections September 2014 74 LDC 3736 Quantum Cascade Laser Con
42. SENSor CURRent THERM10UA SENSor CURRent THERM100UA SENSor CURRent RTD1MA SENSor CURRent RTD2_5MA SENSor RESistance COUNts ALL 60 LDC 3736 Quantum Cascade Laser Controller CALibrate VMEAS STARt CALibrate VMEAS DATA lt nrf gt Description Begins Takes data for the laser voltage calibration procedure if the laser diode mode is selected or for the TEC voltage calibration procedure if the TEC controller mode is selected see the INSTrument SELect command Parameters DATA a number representing the measured voltage in Volts CALibrate SENSORI STARt Description Begins the TE ICI sensor voltage calibration procedure CONDition Description Reports the selected instrument s Condition status register See section 3 Status Reporting Example INST las Condition A response of 1025 bits 10 and 0 set indicates the output is on and the laser is in current limit DISPlay BRIGhtness lt nrf gt DISPlay BRIGhtness Description Sets Reports brightness setting of the front panel displays Parameters brightness an integer from 0 10 representing the level of brightness desired 1 minimum brightness 10 full brightness DISPlay ENABle lt nrf gt DISPlay ENABle Description Sets Reports on off state of the front panel displays Parameters on state 0 for off 1 for on ENABle CONDition lt nrf gt ENABle CONDition Description Sets or reports the selected instrument s Condition Enabl
43. Ve ch User s Guide quantum Cascade Laser Controller LDC 3736 NN DIN Ligiivens ILX Lightwave 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 www newport com ilxlightwave 700483 September 2014 Table of Contents Safety Information and the Manual V General Safety Considerations eekEEEEEEEEEKEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE V Safety SYMMONS ET vi Safety Marking e EE vii WOMAN e vii Rini 16 a q SO PIE SON SA DRE PORN NPR RD VR PRN VP DR VAN PAR PR VA vii Returning an INSETO one n nn ege viii Claims for Shipping RB Lu LEE viii Comments Suggestions and Problems sees eee ix Chapter 1 Introduction and Specifications ccccsseeeeeeeeeeeeeeeeeeeeeeeeees 1 Safety Considerations EE 1 Aital Eelere EE EE EE SE 1 Shipping NIL endeared are elias ata ae ie be tia tis a iaa aa a ee Aaa a a lata ada a a Res 1 Product NEVE nadas ca a a RS E A A ID Ee 2 Tete Ta Tas Beer 3 LE DC 37 36 Sp ci a OS EE 4 Chapter 2 General Operaton ANNE 7 Grounding Requirements cseeeceeeeeeesecceeeeeenceeeeeenceenenenesenenenenenenenenes 7 AC Line Power Requirements esse ee eee eee eee 7 The Power Up SeQUence EE 7 Steet Elle 8 GPIB nl le re WEE 8 USE COMmMUniGanOn ccd L llgen 9 Tilt eleng d EE 9 Rack Klee 9 MEIER ca Pn A Di ined 9 Connecting to the Laser Controller r
44. Ze 1 TEMPerature PROTection LOW lt nrf gt Set TE controller low temperature limit SOURce TEMPerature PROTection LOW Report TE controller low temperature limit SOURce 1 TEMPerature PROTection d Set TE controller high temperature limit HIGH lt nrf gt SOURce 1 TEMPerature PROTection A i E Report TE controller high temperature limit September 2014 48 LDC 3736 Quantum Cascade Laser Controller SOUR Ze 1 TEMPerature SPOint lt nrf gt Set TE controller temperature setpoint SOURCce 1 TEMPerature SPOint Report TE controller temperature setpoint SOURce 1 TEMPerature TOLerance lt nrf gt Set TEC temperature tolerance SOURce 1 TEMPerature TOLerance Report TEC temperature tolerance SOURce 1 VOLTage LIMit lt nrf gt Set laser diode voltage limit SOURce 1 VOLTage LIMit Report laser diode voltage limit SOURce 2 VOLTage LEVel lt nrf gt Set external fan voltage setpoint SOURce 2 VOLTage LEVel Report external fan voltage setpoint SYST ERRor ALL Report all errors in error queue SYSTem ERRor CODE ALL Report all error codes in error queue SYSTem ERRor CODE NEXT 7 Report next error code from error queue SYSTem ERRor COUNt 7 Report the number of errors in the error queue SYSTem ERRor NEXT Report next error from error queue See Purge error queue reset laser controller and TE controller to defaul
45. alid E 342 The measurement calibration has failed E 343 The limit calibration has failed E 344 A calibration memory write error has occurred E 345 A calibration memory read error has occurred E 350 A queue overflow has occurred E 360 General communications error E 361 A parity check error has occurred in the program September 2014 79 LDC 3736 Quantum Cascade Laser Controller Error Code Explanation E 362 A framing error has occurred in the program E 363 An input buffer overrun has occurred E 365 A time out error has occurred E 366 Invalid storage location selected E 402 Temperature sensor open error E 403 TEC open circuit error E 404 TEC current limit error E 405 TEC voltage limit error E 407 TEC temperature limit error E 409 TEC sensor type change detected E 410 TEC out of tolerance value detected E 411 General TEC control error E 412 General TEC programming error E 413 General TEC communications error E 501 Laser interlock error E 503 Laser open circuit error E 504 Laser over current error E 509 Laser temperature out of range error E 520 Digital board EEPROM error E 532 General laser communications error E 533 Laser disabled due to TEC error when TEC Error mode is enabled E 596 Unknown laser board detected September 2014 80 LDC 3736 Quantum Cascade Laser Controller Calibration Overview The LDC 3736 Quantum Cascade Las
46. am data gt Common Command with Numeric Data Figure 3 4 Common Command Diagrams Numeric data is required with RCL 0 10 see front panel RECALL function SAV 1 10 see front panel STORE function and ESE 0 255 see Figure 3 2 GPIB connector diagram All the IEEE 488 2 Common Commands supported by the LDC 3736 are listed below September 2014 39 LDC 3736 Quantum Cascade Laser Controller Table 3 7 IEEE 488 2 Common Commands Supported by LDC 3706 Series instrument CLS ESE ESE ESR IDN OPC OPC RCL RST SAV SRE SRE STB TRG TST WAI See Chapter 4 Command Reference for descriptions of all commands including common commands supported by the LDC 3736 LASER Condition Status Register INST LAS CONDition talufo s 8 7 DDR LOGKAL OR EGEZ LEER SEES A Standard skHppeipwp Pibiiaiziigl Event Status Register Zeep ESR LASER Condition Status Enable Register o INST LAS ENABle CONDition lt nrf gt 15 N A DS INST LAS ENABle CONDition LOGICAL OR T TEBE BED 1 j Standard 1 Event Status 1 Enable Register 1 ESE lt nrf gt i ESE QUEUE 1 NOT EMPTY 1 1 i OUTPUT 1 QUEUE 1 meets a Pe
47. and apply power maintenance information specifications and listings of the LDC 3736 options and accessories v Safety Considerations and unpacking information v Product Overview v Options and accessories v Specifications Safety Considerations M warnine If any of the following symptoms exist or are even suspected remove the LDC 3736 instrument from service Do not use the LDC 3736 instrument until trained service personnel can verify safe operation Visible damage Severe transport stress Prolonged storage under adverse conditions Failure to perform intended measurements or functions If necessary return the LDC 3736 instrument to ILX Lightwave for service and repair to ensure that safety features are maintained Initial Inspection When you receive your LDC 3736 Quantum Cascade Laser Controller verify that the following items were shipped with the instrument LDC 3736 Quantum Cascade Laser Controller Manual Power Cord Shipping Kit LNF 320 Low Noise Filter Shipping Kit The shipping kit for the LDC 3736 Quantum Cascade Laser Controller includes a USB A B cable and a CD containing the ILX Lightwave USB Driver September 2014 1 LDC 3736 Quantum Cascade Laser Controller Product Overview The LDC 3736 Quantum Cascade Laser Controllers are high performance combination current source temperature controllers The current source provides a high stability output with a fully redundant current limit and multiple laser prote
48. ara 12 Front Panel eleien 13 PowerOn OT fA tee eter ee hai ae a it TTT 13 September 2014 i LDC 3736 Quantum Cascade Laser Controller Adjust Knob and Enable Button ee eeee eee ereenn nne ennenen nenen 13 Temperature Controller Getup ear eratareaaa aa r a aa a Ea aaa TA 14 PID Temperature Control 15 Temperature Control Mode A 16 Laser Current Source Getp a aa ar aaa aa a a r Aaaa a Ea aaa aaia 16 Current Control Mode eee 18 Displayeiicscid fe ae ee Ae ee 18 Error Indicators ssa ads ete ee ted aurea lad des gua abl dn ciate tia qua teats Aas 19 General Operating Geier 19 Warm Up and Environmental Considerations eee 19 Operating the Laser Current Source from the Front Panel 19 Using the LDC 3736 Controller s Trigger Output Function ra 22 Operating the Temperature Controller from the Front Panel 22 General Guidelines for Sensor Selection and Safety Limits e 22 sensor Options se co e EE EEN 22 Safety LIMIS EEN 26 Constant Temperature Mode Operation 27 Constant Sensor Mode Operation eeschte erte enee 28 Constant Current Mode Operation 29 Resistive Heater Mode Operaton AA 30 Chapter 3 Remote Operation 31 EIS ACESS ur raia rea E E e aa A bts Mts es Nutt ates 31 Basic GPIB Concepts sacar iara do EL eee 31 Data and Interface Messages e neee nner eenn nenen 31 Talkers Listeners and Controllers ss YET eS e 2202532 V Zx EZET age YZE ET SRE aaa t
49. at a minimum before operating your new controller Power requirements Front panel operation General operating procedures Grounding Requirements The LDC 3736 Quantum Cascade Laser 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 adaptor with the grounding wire connected to an electrical ground safety ground ILX Lightwave recommends connecting the instrument only to properly earth grounded receptacles The power cord connector and power cable meet IEC safety standards AC Line Power Requirements The LDC 3736 Quantum Cascade Laser Controller can be configured to operate at nominal line voltages of either 115 VAC or 230 VAC The user may change the line voltage by a switch on the rear panel These line voltages may vary from nominal by no more than 10 and the frequency of the AC source must be 50 60 Hz For input voltages below 100VAC a de rating of 0 3 V and 0 4 Amps per input AC volt applies down to a minimum of 90 VAC input voltage M warnine Check the power switch on the rear panel is in the proper position prior to power up Damage to internal fuses and other internal circuitry may occur if the wrong line voltage is selected The Power Up Sequence WARNING Prior to power up ensure the fan inlet located on the rear of the instrument has no obstructions that would impede airflow Se
50. ation vi Details about cautionary symbols v Safety markings used on the instrument Y Information about the warranty Y 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 minor 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 M warnine Warning indicates a potentially dangerous situation which can result in serious injury or death Z 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 to your authorized local ILX Lightwave distributor for service or repair to ensure that safety features are maintained All instruments returned to ILX Lightwave are required to have a Return Merchandise Authorization Number assigned by an official representative of ILX Lightwave Corpor
51. ation See Returning an Instrument for more information September 2014 v LDC 3736 Quantum Cascade Laser Controller Safety Symbols This section describes the safety symbols and classifications Technical specifications including electrical ratings and weight are included within the manual See the Table of Contents to locate the specifications and other product information The following classifications are standard across all ILX Lightwave products Indoor use only Ordinary Protection This product is NOT protected against the harmful ingress of moisture IEC Class Equipment grounded type Mains supply voltage fluctuations are not to exceed 10 of the nominal supply voltage Pollution Degree Il Installation overvoltage Category II for transient over voltages Maximum Relative Humidity lt 85 RH non condensing Operating temperature range of 10 C to 40 C Storage and transportation temperature of 40 C to 70 C Maximum altitude 3000 m 9843 ft This equipment is suitable for continuous operation September 2014 vi LDC 3736 Quantum Cascade Laser Controller Safety Marking Symbols This section provides a description of the safety marking symbols that may 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 Caution risk of Protective Caution electric shock
52. be disabled at power up and the unit will automatically configure its parameters to the state which existed when the power was last shut off 3 If the temperature controller is required please refer to the section below on temperature control prior to enabling the laser current output 4 Press the LASER MODE soft button until the CURRENT LED is illuminated 5 Select the maximum output current range for your laser by pressing the RANGE soft button under LASER RANGE For best performance select the lowest range that allows you to run at the maximum desired output current for your laser diode or quantum cascade laser September 2014 19 LDC 3736 Quantum Cascade Laser Controller 6 8 Press LASER under PARAMETER to adjust the laser current limit voltage limit power limit if applicable calibration PD value photodiode reverse voltage bias and LD TEC error link Note For best low noise operation the modulation frequency bandwidth should be set to LOW and the MOD LED should be turned off and the LNF 320 Low Noise Filter should be installed on the back of the instrument Under the ADJUST section press the LASER soft button and use the knob to adjust the output current to your desired output Press the ON soft button under LASER MODE It is advised when using a new laser or connection to the laser to set the output to zero prior to enabling the output Once the output is enabled slowly ramp the current to your desired output The user
53. can display measured voltage photodiode current calculated photodiode power and current setpoint on either the left or right side of the LASER display by pressing the LEFT or RIGHT display soft buttons under the LASER display Operating a Laser in Constant Current Current Mode with Analog Modulation 1 Plug the LDC 3736 into an appropriate AC power source supplying the correct mains voltage and frequency for your instrument refer to the rear panel for the correct ratings Tum on the LDC 3736 The laser output will be disabled at power up and the unit will automatically configure its parameters to the state which existed when the power was last shut off If the temperature controller is required please refer to the section below on temperature control prior to enabling the laser current output Press the LASER MODE soft button until the CURRENT LED is illuminated Select the maximum output current range for your laser by pressing the RANGE soft button under LASER RANGE For best performance select the lowest range that allows you to run at your maximum desired output current for your laser diode or quantum cascade laser Press LASER under PARAMETER to adjust the laser current limit voltage limit power limit if applicable calibration PD value photodiode reverse voltage bias and LD TEC error link Also make sure to adjust to either LOW or HIGH bandwidth mode based on your maximum required modulation frequency The maximum frequen
54. cated on the rear panel of the LDC 3736 instrument that provides the capability to adjust the temperature setpoint by applying a voltage signal The LDC 3736 can accept a signal from 5 V to 5 V with a gain of 2 C V and bandwidth of 5 Hz This feature is useful in applications requiring sweeping of the temperature without using GPIB or USB remote interface External Fan Control The LDC 3736 instrument features the ability to control an external fan through the 25 pin DSUB connector This circuit can provide up to 500 mA and may be controlled from 1 to 12 VDC The circuit will automatically increase the voltage to 12 VDC to start a fan from a stopped condition and will regulate to the desired voltage once more than 20 mA is drawn Pseudo 4 Wire Temperature Control Measurements The LDC 3736 instrument offers a pseudo 4 wire temperature sensor measurement feature which helps to minimize errors induced by cable resistance both in thermistor RTD sensor modes as well as on the TEC output terminals This feature is enabled by connecting the appropriate sense terminals and is disabled by leaving them disconnected External Trigger Output For applications where an external measurement must be made synchronously with the operation of the LDC 3736 a TTL level trigger output is provided September 2014 11 LDC 3736 Quantum Cascade Laser Controller through a grounded female BNC connector on the rear of the instrument For further information pleas
55. cluded in the correct sequence A single white space must separate a command from its parameters or data White space is normally the space character Other control characters are also interpreted as white space Do not use white space before the question mark in a query command More than one command may be in the same command string if the commands are separated with semicolons GPIB uses a flexible representation for numeric parameters integer floating point or engineering scientific notation There are no default values for omitted parameters The following are examples of invalid syntax command strings that will produce errors Table 3 6 Invalid Syntax Command Strings COMMAND COMMENT SOURCE CURR LIM HIGH Missing colon between LIM and HIGH Missing semicolon SYST VERS command causes an error OUTPUT ON SYST VERS DISPLAY Space not allowed before question mark Space missing between LIM command and the SOURCE POW LIM1 2 parameter value 1 2 September 2014 38 LDC 3736 Quantum Cascade Laser Controller IEEE 488 2 Common Commands The IEEE 488 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 SS COMMAND KT Common Command Common Command Query lt decimal lt white space gt numeric progr
56. configuration RST Forces a device reset SAV lt integer gt Saves the current setup configuration SRE lt integer gt E Request Enable Register bits to allow generation of user selectable service SRE Returns the current contents of the Service Request Enable Register STB Returns the current contents of the Status Byte Register 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 September 2014 43 LDC 3736 Quantum Cascade Laser Controller Table 4 2 Instrument Specific Command Summary Reference List NAME FUNCTION CALCulate TRANsform POWer l d SC Set photodiode responsivity RESPonsivity lt nrf gt CALCulate TRANsform POWer A Wis Reports photodiode responsivity RESPonsivity CALCulate TRANsform TEMPerature Set coefficient A CVD A for the Callender Van CVDusen A lt nrf gt Dusen RTD equation CALCulate TRANsform TEMPerature Report coefficient A CVD A for the Callender CVDusen A Van Dusen RTD equation CALCulate TRANSform TEMPerature Set coefficient B CVD B for the Callender Van CVDusen B lt nrf gt Dusen RTD equation CALCulate TRANsform TEMPerature Report coefficient B CVD B for the Callender CVDusen B Van Dusen RTD equation CALCulate TRANsform TEMPerature Set coefficient C CVD C for the Call
57. cter at the end of the command line works acceptably A query has no space between the command string and the question mark For example Table 3 3 Query Formatting ACCEPTABLE NOT ACCEPTABLE DISPLAY DISPLAY Note Too many consecutive white spaces can overflow the data I O buffer Terminators A program message terminator identifies the end of a command string These are the valid terminator sequences lt NL gt lt AEND gt GPIB EOI lt NL gt lt END gt Many computers terminate GPIB strings with lt CR gt lt NL gt lt END gt Carriage Return New Line EOI A carriage return lt CR gt is read as white space The LDC 3736 instrument terminates its GPIB responses with lt CR gt lt NL gt lt 2END gt If problems are encountered with GPIB communications the terminator string can sometimes be the cause Refer to the computer s GPIB controller manual for information on configuring its terminator string Command Separators More than one command may be placed in the same command string if each command is separated by a semicolon The semicolon can be preceded by one or more spaces For example DISPLAY ON IDN READ DISPLAY ON IDN READ September 2014 36 LDC 3736 Quantum Cascade Laser Controller Parameters Some commands require a parameter The parameter must be separated by at least one white space The syntax symbol lt nrf value gt refers to the flexible numeric r
58. ction features The built in temperature controller can work with a wide range of temperature sensors and thermoelectric modules to deliver precise laser temperature control over a wide range of temperatures The LDC 3736 s fast sophisticated GPIB and USB interfaces ensure trouble free remote programming and readout If cleaning is required use a clean dry cloth Do not use solvents Figure 1 1 LDC 3736 Front Panel UNE VOLTAGE _ RATING us 60 MADE IN USA Figure 1 2 LDC 3736 Rear Panel September 2014 2 LDC 3736 Quantum Cascade Laser Controller Options and Accessories Options and accessories available for LDC 3736 Quantum Cascade Laser Controller include the following September 2014 3 LDC 3736 Quantum Cascade Laser Controller LDC 3736 Specifications LASER CURRENT SOURCE LDC 3736 DRIVE CURRENT OUTPUT Output Current Range 0 1000mA 0 2000mA 0 4000mA Setpoint Resolution Display 0 1mA 0 1mA 0 1mA Setpoint Resolution Remote 20pA 40uA 80pA Setpoint Accuracy of FS 0 15 of SP 1mA 0 15 of SP 1mA 0 15 of SP 1mA Compliance Voltage 0 18V adjustable 0 18V adjustable 0 18V adjustable Temperature Coefficient lt 50ppm C lt 50ppm C lt 50ppm C Short Term Stability one hour lt 20ppm lt 20ppm lt 20ppm Long Term Stability 24 hour 3 lt 40ppm lt 40ppm lt 40ppm Noise and Ripple rms High Bandwidth Mode rms 30pA Bu 100pA Low Bandwidth Mode rms 30pA 50A 90pA Low Ba
59. cy bandwidth for each range can be found in the specifications in Chapter 1 Press the soft button under MOD to enable the input BNC jack and connect the voltage signal that will be superimposed on to the output See the Specifications in Chapter 1 for details on transfer function and maximum bandwidth Note that all limits also apply to the modulated output thereby protecting your laser in all operating modes M warnine Be sure not to exceed the specified modulation voltage level or damage to the instrument may result September 2014 20 LDC 3736 Quantum Cascade Laser Controller 8 Under the ADJUST section press the LASER soft button and use the knob to adjust the output current to your desired output Press the ON soft button under LASER MODE Itis advised when using a new laser or connection to the laser to set the output to zero prior to enabling the output Once the output is enabled slowly ramp the current to your desired output 9 The user can display measured voltage photodiode current calculated photodiode power and current setpoint on either the left or right side of the LASER display by pressing the LEFT or RIGHT display soft buttons under the LASER display Operating a Laser in Constant Power Mode The LDC 3736 Quantum Cascade Laser Controller allows you to operate the laser current source driver in a Constant Power mode In this mode the controller drives current to the laser to the extent required to reach a setpoint
60. d measured photocurrent to MDI calibration CALibrate MDI DATA lt nrf gt procedure Initiate photodiode current measurement CALibrate PDI STARt calibration This is the same procedure as CALibrate MDI STARt Send measured photocurrent to PDI calibration CALibrate PDI DATA lt nrf gt procedure CALibrate RTD1OOOUA STARt Initiate 1 mA RTD calibration 2 Send measured RTD resistance to 1 mA RTD CALibrate RTD1000UA DATA lt nrf gt calibration procedure CALibrate RTD2500UA STARt Initiate 2 5 mA RTD calibration Send measured RTD resistance to 2 5 mA RTD CALibrate RTD2500UA DATA lt nrf gt calibration procedure Initiate ICI sensor current measurement CALibrate SENSORI STARt E calibration Send measured ICI sensor current to IC current CALibrate SENSORI DATA lt nrf gt i calibration procedure Initiate ICV sensor voltage measurement CALibrate SENSORV STARt calibration E Send measured ICV sensor voltage to sensor CALibrate SENSORV DATA lt nrf gt voltage calibration procedure Set calibration constants manually for various CALibrate VALues lt string gt lt nrf gt lt nrf gt measurements See Command Reference below for more information Report calibration constants for various CALibrate VALues lt string gt measurements See Command Reference below for more information CALibrate VALues ERASe lt string gt Reset ca
61. e IC V calibration procedure has been performed The order in which the procedures are performed is not important 1 Connect a DC ammeter to the sensor pins of the 15 pin output connector of the LDC 3726 3746 pins 7 and 8 or the 25 pin output connector of the LDC 3736 37620 pins 14 and 15 Note the current from the sensor pins should be less than 120 pA 2 Enter the sensor calibration mode by navigating to the 100 yA Cal or 10 pA Cal selection in the Sensor Cal area of the Calibration submenu of TEC parameter menu tree Press the SET button to select the calibration and then press the TEC button to start it 3 Turn the ADJUST knob until the display indicates the same current measured by the DC ammeter 4 Press the TEC button and wait for the 7 segment display to exit the calibration mode Once the calibration is completed the calibration constants will be stored to the non volatile memory and the display will return to its previous state IC I AD590 or equivalent Sensor Calibration The following procedure calibrates the IC sensor measurement so that the temperature measurement will be accurate This procedure does not calibrate C1 and C2 For information on calibrating the IC sensor see Appendix A This procedure uses internal components for its calibration No external components are required Accurate IC measurements require that the IC V the 100 pA thermistor and the IC I calibration procedures have been p
62. e consult the Specifications section of Chapter 1 Connecting to the Laser Controller When connecting your quantum cascade laser or any other sensitive devices to the LDC 3736 Quantum Cascade Laser Controller ILX recommends that the instrument be powered up and the LASER output be in the off position with the ON indicator LED unlit In this condition a low impedance shunt is active across the output terminals When disconnecting devices it is necessary to turn the LASER Output off but the instrument may be left powered on ILX also recommends that the connections to the LDC 3736 output be made using twisted pairs with an earth grounded shield See Figure 2 1 below The output terminals of the instrument are left floating with respect to earth ground to suppress AC power on power off transients that may occur through an earth ground referenced path If the output circuit is earth grounded at any point such as through the laser package and mount the user must be careful to avoid multiple earth ground in the circuit Multiple earth grounds may provide circuit paths that induce spurious currents in the photodiode feedback circuit and output leads 3706 Series Laser Diode Controller Common Laser Cathode Photodiode Cathode Earth Ground 3706 Series Laser Diode Controller Common Laser Anode Photodiode Anode Earth Ground 3706 Series Laser Diode Controller Common Laser Cathode Photodiode Anode Earth G
63. e problem re connect one instrument at a time until the problem returns Then check the other instrument for address conflicts and proper GPIB function The LDC 3736 is not responding to all The LDC 3736 is not fully IEEE 488 2 compliant ANSI IEEE 488 2 commands The LDC 3736 is not being recognized Check the USB cable connection between the LDC 3736 by USB instrument and the computer September 2014 72 LDC 3736 Quantum Cascade Laser Controller No response from a remote command Check that a GPIB or USB A B cable from the system and the RMT indicator is off controller is connected to the LDC 3736 instrument If you are using GPIB the cable should be less than 3 meters 10 feet long Press LOCAL until the GPIB address is displayed If it is not correct change it by using the ADJUST knob until you see the correct address Check that your controlling software is sending commands to the correct GPIB address and using the correct terminating character Check that no two devices are set to the same GPIB address Make sure that there are less than 15 devices on the bus Check that total GPIB cable length is less than 20 meters 65 feet Check the configuration of your GPIB controller card or COM port Specifically note the information regarding the terminating character Remove all other instruments from the GPIB bus to isolate the LDC 3706 Series instrument If this corrects the problem re connect one instrument at a time
64. e status register See section 3 Status Reporting Parameter A number containing the bit encoded value to set in the register Example INST LAS Enable Condition 16 Only bit 4 is set when an interlock error occurs the Laser Condition Summary bit will be set in the Status Byte September 2014 61 LDC 3736 Quantum Cascade Laser Controller EVEnt Description Example Reports the selected instrument s Event status register See section 3 Status Reporting This query will report the event status register then clear the register INST LAS Event A response of 8 bit 3 set indicates that a Power Limit condition occurred since the last read of the Event register ENABle EVEnt lt nrf gt ENABle EVEnt Description Parameter Example Sets or reports the selected instrument s Event Enable status register See section 3 Status Reporting A number containing the bit encoded value to set in the register INST LAS Enable Event 2 Bit 1 is set so a voltage limit event will cause the Laser Event Summary bit to be set in the Status Byte INPut BIAS VOLTage lt nrf gt INPut BIAS VOLTage Description Parameters Reset Value Sets Reports photodiode bias voltage value PD bias 0 000 5 000 the desired PD bias voltage in volts 2 500 V INPut FiLTer LPASs STATe lt bool gt INPut FiLTer LPASs STATe Description Parameters Reset Value Enables Reports state of laser current filter Boolean values
65. ed on the laser diode datasheet September 2014 16 LDC 3736 Quantum Cascade Laser Controller Limits The Limits menu allows the user to select and modify the laser current source limits e Laser Current Limits e Laser Voltage Limits e Laser Power Limits Bandwidth This selects between low bandwidth and high bandwidth modes for the modulation input The maximum frequency for each bandwidth mode is listed in the specifications in Chapter 1 Photodiode Responsivity The photodiode responsivity in yA mW for the laser system currently being controlled is set here Photodiode Bias Voltage The LDC 3736 Quantum Cascade Laser Controller provides an adjustable reverse bias of O 5 VDC for the photodiode The bias can be adjusted by the front panel under the Parameter Laser selection or via GPIB USB TEC Disable Output LD TEC Error when enabled will disable the current source output if the temperature controller exceeds the temperature limits or if the TEC output is disabled either by the user or due to an error When this mode is active the laser current source will not enable unless the TEC output is enabled Brightness This allows the user to select a level of brightness for the front panel displays Values between 1 dim and 10 bright can be selected from the front panel This value can also be controlled remotely see Chapter 4 Laser Calibration This menu allows for calibration of the laser diode current output and reading
66. efficient RO CVD RO for the Callender Van Dusen RTD resistance to temperature equation Parameters CVD RO The resistance of the transducer at O C adjustable from 0 to 9999 9 Ohm Notes The Callendar Van Dusen equation Rr Ball AT BT CT3 T 100 T lt 0 C Rr Ball AT BT T 20 C Where R is the resistance at temperature T Reset Value 100 CAL Culate TRANsform TEMPerature ICI OFFSet lt nrf gt CALCulate TRANsform TEMPerature ICI OFFSet Description Sets Reports offset compensation for a temperature to current transducer Parameters offset 9 999 to 9 999 representing the sensor offset in pA Reset Value 0 CAL Culate TRANsform TEMPerature ICI GAIN lt nrf gt CAL Culate TRANsform TEMPerature ICI GAIN Description Sets Reports slope compensation for a temperature to current transducer Parameters slope 0 to 9 999 representing the slope in pA K Reset Value 1 CALCulate TRANsform TEMPerature ICV OFFSet lt nrf gt CALCulate TRANsform TEMPerature ICV OFFSet Description Sets Reports offset compensation for a temperature to voltage transducer Parameters offset 99 99 to 99 99 representing the sensor offset in mV Reset Value 0 CALCulate TRANsform TEMPerature ICV GAIN lt nrf gt CALCulate TRANsform TEMPerature ICV GAIN Description Sets Reports slope compensation for a temperature to voltage transducer Parameters offset 0 to 99 99 representing the slope in mV K Reset Value 10
67. emperature mode Parameters setpoint 0 000000 10 000000 D value setting Reset Value 0 0 SOURce 1 TEMPerature LCONstants INTegral lt nrf gt SOURce 1 TEMPerature LCONstants INTegral Description Sets reports I term for TEC controller PID loop in Temperature mode Parameters setpoint 0 000000 10 000000 value setting Reset Value 1 0 SOURce 1 TEMPerature LCONstants GAIN lt nrf gt September 2014 67 LDC 3736 Quantum Cascade Laser Controller SOURce 1 TEMPerature LCONstants GAIN Description Sets reports P term for TEC controller PID loop in Temperature mode Parameters setpoint 0 000000 100 000000 P value setting Reset Value 0 5 SOURce 1 TEMPerature PROTection LOW lt nrf gt SOURce 1 TEMPerature PROTection LOW Description Sets reports low limit for temperature Parameters limit 100 00 200 00 low temperature in C Reset Value 100 00 SOURce 1 TEMPerature PROTection HIGH lt nrf gt SOURce 1 TEMPerature PROTection HIGH Description Sets reports high limit for temperature Parameters limit 100 00 200 00 high temperature in C Reset Value 200 00 SOURce 1 TEMPerature SPOint lt nrf gt SOURce 1 TEMPerature SPOint Description Sets reports temperature setpoint Parameters setpoint 100 00 200 00 temperature setpoint in C SOURce 1 TEMPerature TOLerance lt nrf gt SOURce 1 TEMPerature TOLerance Description Sets
68. ender Van CVDusen C lt nrf gt Dusen RTD equation CALCulate TRANsform TEMPerature Report coefficient C CVD C for the Callender CvDusen C Van Dusen RTD equation CALCulate TRANsform TEMPerature Set offset R CVD RO for the Callender Van CVDusen R lt nrf gt Dusen RTD equation CALCulate TRANsform TEMPerature Report offset R CVD RO for the Callender Van CVDusen R Dusen RTD equation CALCulate TRANsform TEMPerature Set gain slope term for ICI current to CI GAIN lt nrf gt temperature equation CALCulate TRANsform TEMPerature Report gain slope term for ICI current to CI GAIN temperature equation CALCulate TRANsform TEMPerature Set offset term for ICI current to temperature CI OFFSet lt nrf gt equation CALCulate TRANsform TEMPerature Report offset term for ICI current to CI OFFSet temperature equation CALCulate TRANsform TEMPerature Set gain slope term for ICV voltage to CV GAIN lt nrf gt temperature equation CALCulate TRANsform TEMPerature Report gain slope term for ICV voltage to CV GAIN temperature equation CALCulate TRANsform TEMPerature Set offset term for ICV voltage to temperature CV OFFSet lt nrf gt equation CALCulate TRANsform TEMPerature Report offset term for ICV voltage to CV OFFSet temperature equation CALCulate TRANsform TEMPerature Set coefficient A in Steinhart Hart resistance SHHart A lt nrf gt to temperature equation for thermistors Report coefficient A i
69. ent range and modulation state Since modulation state can be on or off and there are three laser current ranges this procedure may need to be performed up to 6 times to completely calibrate the system If you do not intend to use any of the ranges or modulation states you may calibrate only the combinations you intend to use For example if you do not intend to use modulation you will only need to calibrate the three current ranges 1 Amp 2 Amp and 4 Amp once each During the calibration procedure the current is driven to two pre determined values 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 3736 then automatically calibrates the laser diode current source and limits 1 Measure and record the exact resistance of a 1 O 25 W resistor A 4 point probe resistance measurement is recommended 2 Connect the 1 O 25 W resistor across the laser output terminals of the LDC 3736 instrument pins 4 5 and 8 9 on the 9 pin connector 3 Navigate to the LDI selection in the Laser Calibration submenu of the laser parameter menu tree 4 Select the LDI calibration mode by pressing the SET button while the LDI selection is displayed Then press the LAS button to start the calibration procedure Calculate the actual current output by using Ohm s Law I V R Where V is the accurately measured voltage across the resistor with a precision mult
70. epresentation defined by the GPIB standard It means that numbers may be represented 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 Table 3 4 Parameters NR1 Integer 20 20 NR2 Floating Point 20 0 20 0 Sere f 2 0E 1 2 0E 1 NR3 Scientific Notation 2 0e 1 2 0e 1 For more information on these definitions refer to the IEEE 488 2 standard There are no default values for omitted parameters If a command is expecting a parameter and nothing is entered an error is generated For further clarity in programming the Boolean values of one 1 and zero 0 may be used Other acceptable names are indicated in Table 3 5 Parameters of a Boolean type are sometimes referred to as lt bool gt Table 3 5 Substitute Parameter Values SUBSTITUTE NAME VALUE ON 1 OFF 0 September 2014 37 LDC 3736 Quantum Cascade Laser Controller Syntax Summary Remote commands must contain all of the letters shown in uppercase in the command definition Optional letters shown in lowercase for some device dependent commands in the command reference Chapter 4 are useful for clarity If any of the optional letters are included they must all be in
71. er Controller should be calibrated every 12 months or whenever performance verification indicates that calibration is necessary All calibrations can be done with the case closed The instrument is calibrated by changing the internally stored digital calibration constants M warna Lasers and TECs should never be connected to the output of the LDC 3736 during calibration procedures All calibration routines have to potential to surpass protection limits and can result in damage to lasers and TECs Recommended Equipment Recommended test equipment for calibrating the LDC 3736 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 calibration equipment DESCRIPTION SPECIFICATION DMM 8 1 2 Digit Metal Film Resistors 5 KQ for all temperature sensors 100 Q for MDI 1 2 KQ and 300 O for 1 mA RTD 60 O and 240 O for 2 5 mA RTD High Power Resistors 1025 W for MDI 2 0150 W for ITE and VTE 4 5 O 100 W for LDI and LDV Optocoupler 0 to 10 mA for photodiode feedback an gt 40 mA maximum input diode current lt 20 mA maximum collector current for MDI Environmental Conditions ILX Lightwave recommends calibration at 23 C 1 0 C When necessary however the LDC 3736 may be calibrated at its intended use temperature if this is within the specified operating temperature range of 10 to 40 C Warm up The LDC 3736 should be al
72. er driver photodiode power limit Parameters limit power limit in Watts Note Maximum value depends on responsivity limited by maximum IPD of 10 mA for 3736 See Calculate Transform Power Responsivity command Reset Value 0 001 Watt 10 0 mW September 2014 65 LDC 3736 Quantum Cascade Laser Controller SOURce 1 POWer LEVel IMMediate lt nrf gt SOURce 1 POWer LEVel IMMediate Description Sets reports laser driver photodiode power setpoint Parameters setpoint power setpoint in Watts Maximum value depends on responsivity Reset Value 0 0 Watts SOURce 1 RESistance LCONstants DERivative lt nrf gt SOURce 1 RESistance LCONstants DERivative Description Sets reports D term for TEC controller PID loop in Sensor mode Parameters setpoint 0 000000 10 000000 D value setting Reset Value 0 05 SOURce 1 RESistance LCONstants INTegral lt nrf gt SOURce 1 RESistance LCONstants INTegral Description Sets reports I term for TEC controller PID loop in Sensor mode Parameters setpoint 0 000000 10 000000 value setting Reset Value 0 1 SOURce 1 RESistance LCONstants GAIN lt nrf gt SOURce 1 RESistance LCONstants GAIN Description Sets reports P term for TEC controller PID loop in Sensor mode Parameters setpoint 0 000000 100 000000 P value setting Reset Value 15 0 SOURce 1 RESistance PROTection LOW lt nrf gt SOURce 1 RESistance PROTection LOW Descri
73. erating mode for the currently SOURce 1 FUNCtion MODE selected instrument mode See Command Reference below for more information SOURce 1 POWer LIMit lt nrf gt Set the photodiode power limit SOURce 1 POWer LIMit Report the photodiode power limit setpoint SOURce 1 POWer L LEVel IMMediate lt nrf gt Set the laser diode power setpoint SOURce 1 POWer L LEVel L IMMediate Report the laser diode power setpoint September 2014 47 LDC 3736 Quantum Cascade Laser Controller SOURce 1 RESistance LCONstants Set the D term for the TEC controller PID DERivative lt nrf gt control loop SOURce 1 RESistance LCONstants Report the D term for the TEC controller PID DERivative control loop SOURce 1 RESistance LCONstants Set the I term for the TEC controller PID NTegral lt nrf gt control loop SOURce 1 RESistance LCONstants Report the I term for the TEC controller PID NTegral control loop SOURce 1 RESistance LCONstants Set the P term for the TEC controller PID GAIN lt nrf gt control loop SOURce 1 RESistance LCONstants Report the P term for the TEC controller PID GAIN control loop SOURce 1 RESistance PROTection LOW lt nrf gt Set the TE controller resistance lower limit SOURce 1 RESistance PROTection LOW Report the TE controller resistance
74. erformed The order in which these three procedures are performed is not important A warnine For IC Current sensors used with the LDC 3736 the 4 wire sensor measurements pins 7 and 8 should not be connected The use of the 4 wire sensor will cause inaccurate sensor measurements 1 Enter the sensor calibration mode by navigating to the ICI Cal selection in the Sensor Cal area of the Calibration submenu of TEC parameter menu tree 2 Select the ICI Cal selection by pressing the SET button and then press the TEC button in order to enable the TEC output This will initiate an auto calibration September 2014 82 LDC 3736 Quantum Cascade Laser Controller 3 Wait Tor the 7 segment display to exit the calibration mode Once the calibration is completed the calibration constants will be stored to the non volatile memory and the display will return to its previous state ICH LM335 or Equivalent Sensor Calibration The following procedure calibrates the IC V sensor measurement so that the temperature measurement will be accurate This procedure does not calibrate C1 and C2 For information on calibrating the IC V sensor see Appendix A This procedure is also required for the other sensor measurements It only needs to be done once 1 Connect a 5 kQ 5 metal film resistor and a precision voltmeter in parallel at the sensor feedback pins of the 15 pin output connector of the LDC 3726 3746 pins 7 and 8 or the 25 pin output c
75. es section in this chapter The setpoint values are indicated by a colon as in Figure 2 3 a and the measured values are indicated by an equal sign as in Figure 2 3 b Figure 2 3a The Setpoint Current Figure 2 3b The Measured Current Temperature Controller Display LEFT Button Left Cycles left half of the left hand TEC display through the available temperature controller measurement and setpoint parameters that can be displayed RIGHT Button Left Cycles right half of the left hand TEC display through the available temperature controller measurement and setpoint parameters that can be displayed Laser Current Source Display LEFT Button Right Cycles left half of the right hand Laser display through the available laser current source measurement and setpoint parameters that can be displayed RIGHT Button Right Cycles right half of the right hand Laser display through the available laser current source measurement and setpoint parameters that can be displayed September 2014 18 LDC 3736 Quantum Cascade Laser Controller When the same parameter is displayed on the left and right display the LDC 3736 will automatically center the parameter and provide the maximum resolution allowed Error Indicators The LDC 3736 instrument indicates operational errors on the measurement display with an error code and brief description of the error that has occurred A complete list of error codes can be found in Chapter
76. for your instrument refer to the rear panel for the correct ratings Tum on the LDC 3736 The output will be disabled at power up and the unit will automatically configure its parameters to the state which existed when the power was last shut off Press the SELECT soft button in the TEC MODE section of the front panel until the TE CURRENT LED is selected Press the TEC button in the PARAMETER section of the front panel to enable the menu structure and adjust the applicable limits sensor type calibration constants and external fan control Use the SET button to select the parameter you wish to adjust and then use the ADJUST KNOB to change the parameter to the desired value Clockwise rotation will increase the parameter and counter clockwise rotation will decrease the parameter Allow the parameter adjustment to time out three seconds or press the SET button to save the new parameter in non volatile memory Adjust the TEC current setpoint by enabling the TEC adjustment mode by pressing the TEC button in the ADJUST section of the front panel and rotate the ADJUST KNOB to the desired value The user can display measured voltage sensor value or temperature or the current setpoint on the TEC side left display by pressing the LEFT left and RIGHT left display buttons Enable the TEC output of the LDC 3736 instrument by pressing the ON soft button left in the TEC MODE section of the front panel This button has a toggling action so press
77. gression of how the user would typically configure the instrument for use for the first time LA Lightwave Figure 2 2 Front Panel Display Power On Off The POWER button applies power to the LDC 3736 instrument and starts the power up sequence described above Adjust Knob and Enable Button The ADJUST knob and enable buttons TEC and LAS located below the ADJUST knob is located on the upper right side of the LDC 3736 front panel It is used to change the setpoints enter parameter values enter the GPIB address enter Save or Recall bin numbers or enter instrument calibration data The enable button LEDs indicate the three modes of operation of the knob September 2014 13 LDC 3736 Quantum Cascade Laser Controller Disabled both LEDs off TEC adjustment enabled TEC LED on and LASER adjustment enabled LAS LED on Temperature Controller Setup SET Button Allows the user to adjust settings under TEC LASER RECALL and STORE The SET button will allow the user to open a sub menu or allow the user to adjust the currently selected parameter When a parameter is being adjusted the units will flash at a constant frequency To return to the main menu the sub menu will contain one option that reads Return lt SET gt TEC Button Uses a menu system for temperature controller setup functions including Limits Sensor Sensor Calibration Constants External Fan Control Cable Resistance and Analog Input The SET button select
78. he thermistor which results in a voltage across the thermistor This voltage is used as a feedback signal by the LDC 3706 Series instrument digital control loops to maintain a constant temperature The thermistor should be connected across the Sensor and Sensor pins pins 1 and 2 of the TEC output connector for the LDC 3736 as described above When using a thermistor in constant temperature mode the quantity that is maintained constant by the controller is the sensor resistance In constant temperature mode the LDC 3736 converts the temperature setpoint to a thermistor resistance setpoint using user defined constants The Steinhart Hart equation is used to convert a temperature to a resistance for thermistor sensors The equation describes the non linear resistance versus temperature characteristics of typical thermistors Calibrating a thermistor consists of measuring its resistance at various September 2014 22 LDC 3736 Quantum Cascade Laser Controller temperatures and fitting this measured data to the Steinhart Hart equation The resulting coefficients C1 C2 and C3 effectively describe the thermistor for a specific temperature range For more information about the Steinhart Hart equation see ILX Lightwave Application Note 4 Thermistor Calibration and the Steinhart Hart Equation To measure the precise temperature of a load you must use a calibrated sensor For example when using a thermistor enter its Steinhart Hart coefficients C1
79. ibration of sensor readings 10 pA thermistor 100 pA thermistor 1 mA RTD 2 5 mA RTD ICI and ICV TEC current output and readings and TEC voltage readings See Chapter 5 for more details September 2014 14 LDC 3736 Quantum Cascade Laser Controller PID Temperature Control SELECT Button Left In PRESET temperature control mode pressing SELECT left displays the available preset gain ranges In MANUAL temperature control mode pressing SELECT left displays the last PID values used and in AUTO TUNE mode pressing SELECT left displays the option to start the auto tune by pressing SET Pressing SELECT left repeatedly or using the ADJUST knob cycles through the presets and PID values SET Button In PRESET temperature control mode pressing SET left selects the preset gain range on the display In MANUAL temperature control mode pressing SET left allows the user to adjust the value currently on the display SET left in the AUTO TUNE mode starts the auto tune procedure MODE Button Cycles through PRESET MANUAL and AUTO TUNE modes The selected mode is indicated by an illuminated LED The output will not be disabled if the user changes the PID Control Mode Preset The user can select one of the preprogrammed gain ranges by first selecting the PRESET LED using the MODE button then pressing the SELECT left button or ADJUST knob to display the correct preset gain for the thermal load and pressing the SET left button t
80. imeter and R is the accurately measured load resistance 5 Turn the ADJUST knob until the display shows the value of the laser current measurement as calculated from step 4 Then press the LAS button 6 The instrument will apply a new current after a short time Repeat step 5 for the second current 7 Wait for the 7 segment display to exit the calibration mode Once the self calibration is completed the calibration constants will be stored to the non volatile memory and the display will return to its previous state Laser Voltage Measurement Calibration The following procedure calibrates the Laser voltage measurement It only needs to be done once the range and modulation selections are not important to the voltage calibration 1 Calibrate the laser current as described in the section above 2 Connect the 4 5 O 100 W resistor across the laser output terminals of the LDC 3736 instrument pins 4 5 and 8 9 on the 9 pin connector 3 Connect a calibrated DMM across the load resistor Navigate to the LDV selection in the Laser Calibration submenu of laser parameter menu tree 4 Enter the calibration mode by pressing the SET button while the LDV selection is shown on the display Then press the LAS button to start the calibration process 5 Measure the voltage using the DMM Adjust the voltage shown on the lower display to the match your measured voltage by turning the ADJUST knob Then press the LAS button 6 The inst
81. ing this button once more will disable the TEC output September 2014 29 LDC 3736 Quantum Cascade Laser Controller Resistive Heater Mode Operation 1 Plug the LDC 3736 Controller into an AC power source supplying the correct mains voltage and frequency for your instrument refer to the rear panel for the correct ratings Tum on the LDC 3736 The TEC output will be disabled at power up and the unit will automatically configure its parameters to the state which existed when the power was last shut off Press the SELECT soft button in the TEC MODE section of the front panel until the TEMPERATURE LED on the SENSOR LED is selected Press the TEC button in the PARAMETERS section of the front panel to enable the menu structure and adjust the applicable limits sensor type calibration constants and external fan control Use the SET button to select the parameter you wish to adjust and then use the ADJUST KNOB to change the parameter to the desired value Clockwise rotation will increase the parameter and counter clockwise rotation will decrease the parameter Allow the parameter adjustment to time out three seconds or press the SET button to save the new parameter in non volatile memory For Resistive Heater Mode ensure that the positive current limit I is set to zero Adjust the TEC temperature or sensor value setpoint by enabling the TEC adjustment mode by pressing the TEC button in the ADJUST section of the front panel and rotate the ADJUST
82. ion September 2014 69 LDC 3736 Quantum Cascade Laser Controller September 2014 70 LDC 3736 Quantum Cascade Laser Controller Chapter 5 Troubleshooting and Calibration This chapter will help you resolve any problems you may experience with your LDC 3736 Quantum Cascade Laser Controller quickly If you need additional help please contact ILX Lightwave Customer Service See page ix for contact information ILX Lightwave Corporation provides in house calibration services for ILX instruments International customers may contact our service centers for regional calibration support Most ILX instruments including the LDC 3736 requires 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 pre calibration out of tolerance conditions is available upon request Calibration turn around times are normally five business days or less Please contact ILX Customer Support see Comments Suggestions and Problems on page ix for contact information for additional calibration information For further assistance with technical solutions and troubleshooting visit www newport com ilxlightwave Sep
83. is on Operation Complete Query Description Parameters Notes Examples RCL lt bin gt Recall Description Parameters Notes Examples RST Reset Description Parameters Notes September 2014 Places an ASCII character 1 into the instrument s output queue when all pending operations have been finished None This command is a sequential command that holds off all subsequent commands until the 1 is returned Make sure you have set the timeouts appropriately for using this command when you expect long delays OPC A response of 1 means that all overlapped commands are complete Recalls a stored setup configuration from memory A value from 0 10 Bin 0 is the factory set default configuration The SAV function is used to save configurations for convenient recall The current setup is automatically stored and recalled at the next power on RCL 0 response instrument is reconfigured to factory default settings Performs a device reset None 1 Clears OPC or OPC device requirements 2 Stops operation of overlapped commands 3 Sets all device specific function to a known state RST Value The reset command does NOT affect the following Output Queue Enable Registers Event Registers PSC state Memory contents associated with SAV EN AGO 52 LDC 3736 Quantum Cascade Laser Controller SAV lt bin gt Save Description Saves the current instrument configuration
84. ist The SYST ERR query returns a string containing the next error message that is in the error message queue Error Code Tables The error codes are classified and placed in tables corresponding to their classification The classifications are Command Errors Execution Errors Device Errors Query Errors and Instrument Specific Errors Table 5 1 Error Code Classifications Error Code Range Area of Operation E 001 E 099 Internal Program Errors E 100 E 199 Parser Errors E 200 E 299 Execution Control Errors E 300 E 399 Device Specific Errors E 400 E 499 TEC Control Errors E 500 E 599 Laser Control Errors Note Error codes not listed are reserved for future design use Table 5 2 Error Messages Error Code Explanation E 100 General command parsing error E 101 Invalid character E 102 Syntax error E 103 Invalid separator E 104 Data type error E 108 Invalid parameter for command E 109 Command is missing a parameter E 110 Command header error E 111 Command header separator error E 112 Program mnemonic is too long E 113 Undefined command header E 114 Header suffix is out of range E 115 Unexpected number of parameters received E 120 General numeric data error E 121 Invalid character included in numeric data September 2014 76 LDC 3736 Quantum Cascade Laser Controller
85. libration constants to default settings September 2014 45 LDC 3736 Quantum Cascade Laser Controller CALIbrate VMEAS STARt lt nrf gt Initiate LDV or VTE measurement calibration based on which instrument mode is currently selected CALIbrate VMEAS DATA lt nrf gt Send measured LDV or VTE voltage to VMEAS calibration procedure CONDition Report selected instrument s Condition status register DISPlay BRIGhtness lt nrf gt Set display brightness DISPlay BRIGhtness Report display brightness setting DISPlay ENABle lt nrf gt Turn display on or off DISPlay ENABle Reports display on or off condition ENABle CONDition lt nrf gt Set value of selected instrument s Condition Enable register ENABle CONDition Report value of selected instrument s Condition Enable register EVEnt 7 Report selected instrument s Event status register ENABle EVEnt lt nrf gt ENABle EVEnt Set value of selected instrument s Event Enable register Report value of selected instrument s Event Enable register NPut BIAS VOLTage lt nrf gt Set photodiode bias voltage NPut BIAS VOLTage Report photodiode bias voltage NPut FILTer LPASs STATe lt bool gt Enable or disable laser current low pass filter NPut FILTer LPASs STATe Report state of low pass filter NSTrument CATalog
86. ller mode MEASure SENSor Description Reports the currently selected sensor s native quantity For a resistive sensor response value is in ohms For ICI response is in uA For ICV response is in mV OUTPut 1 STATe lt bool gt OUTPut 1 STATe Description Sets reports laser output state in laser driver mode or TEC output state in TEC controller mode Parameter state 0 or 1 O for off 1 for on Also ON or OFF September 2014 63 LDC 3736 Quantum Cascade Laser Controller OUTPut2 STATe lt bool gt OUTPut2 STATe Description Sets reports external fan output state Parameter state 0 or 1 0 for off 1 for on SENSor lt string gt SENSor Description Sets reports sensor type for TEC controller Parameters sensor type string representing what type of sensor will be used Notes Acceptable strings for first parameter THERM100uA THERM10uA RTD1MA RTD2_5MA ICI ICV THERM_AUTO RTD_AUTO DEFault default is the same as THERM AUTO SOURce 1 AM STATe lt nrf gt SOURce 1 AM STATe Description Sets reports enabled state of laser driver analog modulation Parameters state 0 or 1 0 for off 1 for on SOURce 1 CURRent LIMit HIGH lt nrf gt SOURce 1 CURRent LIMit HIGH Description Sets reports upper TEC current limit Parameters upper limit 0 00 8 00 upper current limit in Amps Reset Value 8 00 SOURce 1 CURRent LIMit LOW lt nrf gt SOURce 1 CURRent LIMit
87. lowed to warm up for at least 1 hour before calibration unless otherwise specified Calibration Adjustments There are sixteen calibrations that need to be completed for proper operation of the LDC 3736 Quantum Cascade Laser Controller These calibrations pertain to temperature sensor measurement the ITE current measurement the TEC voltage measurement the laser source current measurement the laser source voltage measurement and the photodiode current measurement September 2014 81 LDC 3736 Quantum Cascade Laser Controller If a problem arises during calibration which prevents normal completion calibration may be aborted by allowing the calibration procedure to time out by not pressing any front panel buttons turning any knobs or sending any remote commands This prevents alteration of stored calibration values due to the fact that new values are not saved to non volatile memory until the last step of each calibration procedure is complete Thermistor Calibration The following procedure calibrates the 100 pA or 10 pA constant current sources so that thermistor resistance measurements will be accurate This procedure does not calculate C1 C2 and C3 For information on calibrating the thermistor sensor see Application Note 4 Thermistor Calibration and the Steinhart Hart Equation The first part of the calibration is to determine an accurate value for the sensor current 10 pA or 100 yA Thermistor resistance measurements require that th
88. mand and will block other commands from execution until it has completed Examples TST A response of O means tests completed without errors WA Wait to Continue Description Prevents the instrument from executing any further commands until all pending operations are complete Parameters None Notes This command can be used to make the instrument wait until an operation is complete before continuing Care should be taken to set the time out appropriately for use with the WAI command After this command is sent the instrument may block subsequent commands waiting for the input queue to empty Examples OUTPUT ON WAI MEAS T The temperature measurement will occur after the output is on September 2014 54 LDC 3736 Quantum Cascade Laser Controller The following pages contain a reference for device dependent commande of the LDC 3736 Quantum Cascade Laser Controller CALCulate TRANsform POWer RESPonsivity lt nrf gt CAL Culate TRANsform POWer RESPonsivity Description Sets Reports photodiode responsivity Parameters uA mW 0 0 to 1000 0 representing photodiode responsivity Reset Value 0 0 CALCulate TRANsform TEMPerature CVDusen A lt nrf gt CALCulate TRANsform TEMPerature CVDusen A Description Sets Reports coefficient A CVD A for the Callender Van Dusen RTD resistance to temperature equation Parameters CVD A 9 999 to 9 999 representing the first coefficient of the Callendar Van Dusen equation multiplied by 10
89. mote 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 EOI end or identify is used by talkers to identify the end of a message Reading the GPIB Address Before operating the LDC 3706 Series instrument remotely its GPIB address must be known Simply press the LOCAL button in the COMM section of the front panel until GPIB Address is displayed on the display The factory default address is 1 Changing the GPIB Address Every device on the GPIB bus must have a unique address If it is necessary to change the address press the LOCAL button in the COMM section of the front panel until the GPIB address is displayed Then adjust the knob until the desired address value is shown The new GPIB address is stored in nonvolatile memory when the display times out The allowable address range is 1 30 for primary GPIB addressing It is not recommended that zero be used for an address as that is typically reserved for the GPIB controller installed in the computer Extended GPIB addressing is not implemented Basic USB Concepts Universal Serial Bus USB is a specification to establish communication between devices and a host controller which has effectively replaced a variety of earlier interfaces such as serial and parallel ports There are several USB standards available including USB 1 1 US
90. mperature when utilizing an RTD sensor Where Ro is the resistance of the RTD at 0 C Typical RTDs have a nominal resistance Ro of 100 O or 1000 O Common Callendar Van Dusen constants are listed below and are used as default values in the LDC 3706 Series Laser Diode Controller e A 3 908 x 10 e 5 775 x 107 e C 4 183 x 10 For optimal accuracy and stability the 1 mA current source should be selected for RTD sensors with resistance of 200 O to 1500 O and the 2 5 mA range should be used with resistance of 1 O to 200 Q In general the change in resistance per change in temperature is much lower for a typical 100 O RTD than that of a typical 10 KO thermistor The proportional and integral terms September 2014 25 LDC 3736 Quantum Cascade Laser Controller for the PID loop must be increased appropriately when using an RTD sensor for optimal setting time and stability Safety Limits TEC modules may be damaged by excessive current so module manufacturers typically specify a maximum safe operating current for their module The temperature controller of the LDC 3736 provides a current limit feature that allows you to set the maximum current that the temperature controller supplies It is normal for the controller to operate at the current limit especially when the load temperature is far from the setpoint The current limit LED will be lit in the TEC section left of the front panel when the controller is in a current limited condition
91. n Steinhart Hart CALCulate TRANsform TEMPerature resistance to temperature equation for SHHart A thermistors CALCulate TRANsform TEMPerature Set coefficient B in Steinhart Hart resistance SHHart B lt nrf gt to temperature equation for thermistors S Report coefficient B in Steinhart Hart CALCulate TRANsform TEMPerature resistance to temperature equation for SHHart B thermistors CALCulate TRANSform TEMPerature Set coefficient B in Steinhart Hart resistance September 2014 44 LDC 3736 Quantum Cascade Laser Controller SHHart C lt nrf gt to temperature equation for thermistors Report coefficient B in Steinhart Hart CALCulate TRANsform TEMPerature resistance to temperature equation for SHHart C thermistors Initiate calibration of 100 pA thermistor CALibrate CURIOOUA STARt current source Send measured current to 100 pA calibration CALibrate CURIOOUA DATA lt nrf gt procedure 2 Initiate calibration of 10 pA thermistor current CALibrate CUR1OUA STARt source Send measured current to 10 pA calibration CALibrate CURIOUA DATA lt nrf gt procedure Update calibration date of instrument LAS TEC CALibrate DATE lt nrf gt lt nrf gt lt nrf gt Parameters are month date year CALibrate DATE Report calibration date of instrument i Initiate photodiode current measurement CALibrate MDI STARt calibration Sen
92. ndwidth Mode with LNF 320 10yA 15pA 50pA Transients Operational lt 4mA lt 4mA lt 4mA 1 kV EFT Surge lt 15mA lt 8mA lt 15mA lt 8mA lt 15mA lt 8mA COMPLIANCE VOLTAGE ADJUST Range 0 18V 0 18V 0 18V Setpoint Resolution Display DIV DIV DIV Setpoint Resolution Remote 60mV 60mV 60mV Accuracy 2 5 42 5 2 5 DRIVE CURRENT LIMIT SETTINGS Range 1 1010mA 1 2020mA 0 4040mA Resolution 5mA 10mA 20mA Accuracy 20mA 40mA 101mA PHOTODIODE FEEDBACK Type Differential Differential Differential Photodiode Reverse Bias 0 5V adjustable 0 5V adjustable 0 5V adjustable Photodiode Current Range 5 to 10000pA 5 to 10000pA 5 10000yA Output Stability 0 02 0 02 0 02 Setpoint Accuracy 0 05 of FS 0 05 of FS 0 05 of FS EXTERNAL ANALOG MODULATION Input 0 10V 1 kQ 0 10V 1 kQ 0 10V 1 kQ Transfer Function 100mA V 200mA V 400mA V Bandwidth 3dB High Bandwidth DC to 250kHz DC to 250kHz DC to 250Hz Low Bandwidth DC to 17kHz DC to 17kHz DC to 17Hz TRIGGER OUTPUT Type TIL TIL TIL Pulse Width 10 ps 10 ps 10 ps Delay 2 5mS 2 5mS 2 5mS MEASUREMENT DISPLAY Output Current Range 0 1000 0mA 0 2000 0mA 0 4000mA Resolution 0 1mA 0 1mA 0 1mA Accuracy 0 1 FS 0 1 FS 0 1 FS Photodiode Current Range 0 10000pA 0 10000pA 0 10000pA Resolution 1pA 1pA 1pA Accuracy 4uA 4uA 4uA Photodiode Responsivity Range uA mW 0 00 1000 00 0 00 1000 00 0 00 1000 00 Resolution 0 01pA mW 0 01pA mW 0 01pA mW Optical Power Range
93. nstall the USB Driver found on the accompanying CD or from the ILX Lightwave website prior to connecting the unit to the PC Please refer to Chapter 3 for more detailed instructions on operating the instrument through USB Tilt Foot Adjustment The LDC 3736 Quantum Cascade Laser Controller has front legs that extend to make it easier to view the display To use them rotate the legs downward until they lock into position Rack Mounting The LDC 3736 Quantum Cascade Laser Controller may be rack mounted by installing the appropriate rack mount flange on either side of the enclosure All rack mount accessory kits contain detailed mounting instructions Refer to the Options and Accessories table in Chapter 1 for applicable rack mount accessory part numbers Connections Current Source Output A 9 pin D sub connector is located on the rear panel of the instrument The connections for this connector are shown below LDC 3736 5 1 O O O O O O O O O 9 6 PIN NUMBER CONNECTION 1 Interlock Interlock Chassis Ground Laser Cathode Voltage Sense Laser Cathode Photodiode Cathode Photodiode Anode Laser Anode Voltage Sense Laser Anode O JO N IO AJOIN 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 current source output connector The short can be a direct short across the pins or a switch
94. nt Therefore when accuracy is not critical offset should be set to a nominal value of O and slope should be set to a nominal value of 1 when the selected sensor is an IC I or set to a nominal value of 10 when the selected sensor is an IC V In order to calibrate an IC sensor device the sensor must be operated at an accurately known stable temperature For example the sensor may be calibrated at O C if the sensor is placed in ice water until its temperature is stable A highly accurate temperature probe thermometer environmental cnamber etc may also be used to determine the known temperature for calibration This appendix contains one and two point calibration methods for IC sensor devices These methods will work for either type of device AD590 Sensor The AD590 is a linear IC thermal sensor which acts as a constant current regulator It produces a current which is directly proportional to absolute temperature over its useful range 50 C to 150 C This nominal value can be expressed as 1pA K Where is the nominal current produced by the AD590 and K is the temperature in Kelvin The LDC 3736 uses current to determine the nominal temperature T by the formula T 1 14A K 273 15 Where T is in C The temperature T which is displayed by the LDC 3736 instrument is first calibrated as follows T C1 C2 T Where offset and slope are the constants stored by the user in the LDC 3736 Series instrument f
95. o select the gain Presets have also been implemented for specific ILX Lightwave mounts When a preset has been selected for a mount the LDC 3736 instrument will set the PID values sensor type and current limits The following mounts are directly compatible with the LDC 3736 instrument LDM 4872 Quantum Cascade Laser Mount Manual In MANUAL mode the user can adjust the PID values or view the preset PID values that were last loaded note if the user adjusts the preset PID values in manual PID mode the change will not permanently affect the preset PID value To manually adjust the PID values first select the MANUAL LED by pressing MODE then press SELECT left to change between P and D To adjust the PID value press SET left to move to the next value press SELECT left To load a preset PID value use the MODE button to cycle to the MANUAL LED and then press the SELECT left button then using the SELECT left or ADJUST knob display the Adjust Preset menu Press the SET left button and cycle through the presets until the correct preset is displayed then press the SET button to load the values Use the SELECT left button to view the loaded preset P and D values Auto tune The auto tune mode will calculate a thermal system s PID coefficients through an iterative PID temperature control process To enter the auto tune mode first press MODE until the AUTO LED is illuminated and then SELECT to ready the instrument for the auto
96. onnector of the LDC 3736 37620 pins 14 and 15 2 Enter the sensor calibration mode by navigating to the ICV Cal selection in the Sensor Cal area of the Calibration submenu of TEC parameter menu tree 3 Select ICV Cal by pressing the SET button and then press the TEC button in order to enable the first sensor current 4 Turn the ADJUST knob until the display indicates the same voltage as shown on the precision voltmeter 5 Press the TEC button in order to enable the second sensor current 6 Turn the ADJUST knob until the display indicates the same voltage as shown on the precision voltmeter 7 Press the TEC button and wait for the 7 segment display to exit the calibration mode and reflect the entered sensor resistance setpoint Once the calibration is completed the calibration constants will be stored to the non volatile memory and the display will return to its previous state RTD Sensor Calibration The following procedure calibrates the 1 mA and 2 5 mA RTD temperature sensors so that the resistance measurements will be accurate This procedure does not calculate Ro A Band C For information on calibrating the RTD sensor itself see Application Note 4 Thermistor Calibration and the Steinhart Hart Equation 1 mA RTD 1 Measure and record the exact resistance of a 300 O and 1200 Q metal film resistor A 4 point probe resistance measurement is recommended 2 Connect the 300 Q resistor to the sensor pins of the 15 pin o
97. ons or comments to ILX Lightwave Customer Support You may contact us in whatever way is most convenient Phone 800 459 9459 or 406 586 1244 Fax 406 586 9405 E mail sales ilxlightwave com Or mail to ILX Lightwave Corporation 31950 East Frontage Road Bozeman Montana U S A 59715 8642 www newport com ilxlightwave When you contact us please have the following information Model Number Serial Number End user Name Company Phone Fax Description of what is connected to the ILX Lightwave instrument Description of the problem Sie NC a e If ILX Lightwave determines that a return to the factory is necessary you are issued a Return Merchandise Authorization RMA 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 in a container with at least 3 inches 7 5 cm of compressible packaging material on all sides We look forward to serving you even better in the future September 2014 ix LDC 3736 Quantum Cascade Laser Controller September 2014 x LDC 3736 Quantum Cascade Laser Controller Chapter 1 Introduction and Specifications This chapter is an introduction to the LDC 3736 Quantum Cascade Laser Controller and contains unpacking information instructions on how to install
98. ontrol mode unless the Local Lockout state has been activated by the host computer Local Lockout disables all front panel controls including the Local button until this condition is changed by the host computer When the instrument is placed in Local Lockout Mode by the host computer the Remote indicator will light on the instrument display GPIB vs USB Communication The USB interface uses the same command set as the GPIB interface Command syntax does not vary between communication protocols However the commands which affect GPIB hardware operation will not be useful For example SRE may be sent using USB but service request SRQ normally supported by GPIB would not be visible since USB has no hardware to support it This is because SRQ is a function of the GPIB interface hardware and is not available via USB The 3736 acknowledges all commands received by the USB interface by transmitting Ready when the command operation is complete Queries are acknowledged by a response message that is specific to the query Multiple commands queries separated by semicolons and issued as one command string are only acknowledged with a Ready response if the entire command string contains no queries See the Command Separators section later in this chapter for additional details The LDC 3736 terminates all responses it transmits with lt CR gt lt LF gt Carriage Return Line Feed characters The LDC 3736 expects all commands or que
99. or the AD590 The AD590 measurement is calibrated at the factory with C2 1 and C1 0 nominal values The AD590 grades of tolerance vary but typically this means that without adjusting C1 or C2 the temperature accuracy is 1 C over its rated operating range If C1 and C2 are also calibrated the temperature accuracy is 0 2 C over its rated operating range However the AD590 is not perfectly linear and even with C1 accurately known there is a non linear absolute September 2014 89 LDC 3736 Quantum Cascade Laser Controller temperature error associated with the device This non linearity is shown in Figure A 1 reprinted from Analog Devices specifications where the error associated with C1 is assumed to be zero ABSO ERR DEGREES C Figure A 1 Non Linearity Graph If a maximum absolute error of 0 8 C is tolerable over the entire temperature range the one point calibration of C1 should be used If C1 is calibrated at 25 C and the intended operating range is 0 to 50 C a maximum error of about 0 2 C may be expected over that operating range If a greater accuracy is desired the two point method of determining C1 and C2 should be used Note however the absolute error curve is non linear therefore the constant C2 will vary over different temperature ranges LM335 Sensor The LM335 is a linear thermal sensor which acts as a constant voltage regulator It produces a voltage V which is directly
100. power value in mW The control loop feedback parameter is photodiode current which the controller converts into optical power via the user defined Photodiode Responsivity Parameter If laser power changes due to internal or external environmental conditions the controller will increase or decrease the current to the laser as appropriate in order to maintain the power setpoint 1 Plug the LDC 3736 instrument into an appropriate AC power source supplying the correct mains voltage and frequency for your instrument refer to the rear panel for the correct ratings Turn on the LDC 3736 The laser output will be disabled at power up and the unit will automatically configure its parameters to the state which existed when the power was last shut off If the temperature controller is required please refer to the section below on temperature control prior to enabling the laser current output Press the LASER MODE soft button until the POWER LED is illuminated Select the maximum output current range for your laser by pressing the RANGE soft button under LASER RANGE For best performance select a range closest to your maximum output current for your laser diode or quantum cascade laser Press LASER under PARAMETER to adjust the laser current limit voltage limit power limit calibration PD responsivity value photodiode reverse voltage bias and LD TEC error link To calculate the calibrated photodiode responsivity value first measure the outp
101. ps respectively When autotune is started by the user the instrument will set the current to the minimum TEC current level which causes the maximum possible rate of heating When the instrument detects that the temperature has reached the temperature setpoint value Point 1 on graph the PID calculation procedure begins During autotune anytime the actual temperature exceeds the setpoint temperature the current is set to the maximum TEC current value which causes the maximum possible rate of cooling This is seen on the graph at point 1 and point 2 When the temperature exceeds the setpoint temperature at point1 the current immediately switches to the maximum value as seen at point 2 Eventually the September 2014 93 LDC 3736 Quantum Cascade Laser Controller temperature setpoint will fall below the setpoint temperature and the current will be set to the minimum current value which causes the maximum possible rate of heating This is seen on the graph at point 3 and point 4 When the temperature falls below the setpoint temperature at point 3 the current immediately switches to the minimum value as seen at point 4 This cycling of current from heating to cooling occurs 10 times during an autotune procedure This is why there are 10 cycles shown between point1 and point 9 on the graph After the first three cycles have been completed point 5 on the graph the autotune procedure begins to record the information needed to determine the PID
102. ptember 2014 7 LDC 3736 Quantum Cascade Laser Controller M warnine Never position the instrument such that the power cord is difficult to remove Never use a power cable with ratings other than those of the original power cord that was shipped with the instrument by ILX Lightwave With the LDC 3736 instrument connected to an appropriate AC power source verify the requirements of the instrument listed on the rear panel prior to connection to an AC mains supply pressing the POWER button supplies AC line power to the instrument and starts the power up sequence The power up sequence consists of the following steps each lasting two to three seconds e All front panel indicators are ON all 7 segment displays indicate 8 e All front panel indicators OFF e Left display shows the model number the serial number and the firmware version of the controller e The displays show the calibration dates for the instrument During the front panel indicator test the LDC 3736 instrument performs a self test to ensure that the internal hardware and software are communicating properly If the LDC 3736 instrument cannot successfully complete the test an error message is displayed See Chapter 5 for a complete list of error messages After the self test the LDC 3736 instrument configuration is set to the same state as when the power was last turned off To quickly set a different configuration you can use the recall function See the Store Button and
103. ption Sets reports TE sensor resistance low limit Parameters low limit 0 00 500000 0 limit in O Reset Value 0 00 September 2014 66 LDC 3736 Quantum Cascade Laser Controller SOURce 1 RESistance PROTection HIGH lt nrf gt SOURce 1 RESistance PROTection HIGH Description Sets reports TE sensor resistance high limit Parameters high limit 0 00 500000 0 limit in Q Reset Value 500000 0 SOURce 1 RESistance SPOint lt nrf gt SOURce 1 RESistance SPOint Description Sets reports TE controller resistance setpoint Parameters setpoint 0 00 500000 0 setpoint in O SOURce 1 RESistance TOLerance lt nrf gt SOURce 1 RESistance TOLerance Description Sets reports TE controller resistance tolerance This setting is used in status reporting see section 3 When the measured resistance is more than this amount over the setpoint the Out of Tolerance bit will be set in the condition register The bit will also be set if the measured resistance is less than this amount below the setpoint Parameters The tolerance value in Q SOURce 1 TEMPerature AM STATe lt nrf gt SOURce 1 TEMPerature AM STATe Description Sets reports TE analog modulation enabled state Parameters state O or 1 O is disabled 1 in enabled SOURce 1 TEMPerature LCONstants DERivative lt nrf gt SOURce 1 TEMPerature LCONstants DERivative Description Sets reports D term for TEC controller PID loop in T
104. reports TE controller temperature tolerance This setting is used in status reporting see section 3 When the measured tempeature is more than this amount over the setpoint the Out of Tolerance bit will be set in the condition register The bit will also be set if the measured temperature is less than this amount below the setpoint Parameters The tolerance value in degrees C September 2014 68 LDC 3736 Quantum Cascade Laser Controller SOURce 1 VOLTage LIMit lt nrf gt SOURCce 1 VOLTage LIMit Description Sets reports laser diode voltage maximum setpoint Parameters maximum voltage 0 000 18 000 maximum voltage in Volts Reset Value 9 000 SOURce2 VOLTage LEVel lt nrf gt SOURce2 VOLTage LEVel Description Sets reports external fan voltage setpoint Parameters fan voltage 0 12 external fan voltage in Volts Reset Value 12 SYSTem ERRor ALL Description Reports all errors in error queue SYSTem ERRor CODE ALL Description Reports all error codes in error queue SYSTem ERRor CODE NEXT Description Reports next error code from error queue SYSTem ERRor COUNt Description Reports the number of errors in the error queue SYSTem ERRor NEXT Description Reports the next error from the error queue SYSTem PRESet Description Purges error queue and resets laser controller and TE controller to default settings SYSTem VERSion Description Reports currently installed firmware vers
105. ria 31 GPIB Cable ele 32 RH EE Heen ee EE 33 Reading the GPRIB AddresS TT 34 Changing the GPIB Address egene EENS ARRI ERNES ee e 34 Basic USB Concepts pane eeir et Tara a na Sa a eira aa da 34 Changing Between Local and Remote Operation 35 ablenne EE pele Rel el A R 35 Command Sy MAK EE 35 LGG eee ee EA e adia Ed da EERE CET o da A dA Riad a ES 35 Vie 36 Kul e 36 IR eT ale io Re TEE 36 EINEN 37 September 2014 ii LDC 3736 Quantum Cascade Laser Controller Syntax SuMMary EE 38 IEEE 488 2 Common Commandes 39 Command ING EE 41 Sequential Overlapped Commande tt 41 Query Response Timing eege EE 41 Chapter 4 Command Heterence AAA 43 Remote Command Reference Summary eee 43 Command WEEN 50 Chapter 5 Troubleshooting and Calibration sss eee eee e e 71 Troubleshooting REI TN 72 ele E EE 76 Error Code Tables m nen ane a ee eee ates ed A Ee 76 Elle WEE 81 Recommended Eouipment sss esse sese eee eee eee eee EN Environmental Conditions inssi ie KENNEN ENEE NEEN ee EN VE Tu ET e OTT EN Calibration Adjustments sorreran dee dE ee Nee diel dee eee EN Thermistor Calibration seieren NEE Eeer 82 IC I AD590 or equivalent Sensor Calibration rare naarraaaaaenaa 82 IC V LM335 or Equivalent Sensor Calibration eee ee 83 RID Sensor Calibration BEE 83 ILE Current Calibration 2 52 22220 Facstialtscatios asia a a aae aaa be odio aaa aa alba ahi Riad Lala Lendas 85 TEC Voltage
106. ries to be terminated with a lt CR gt Carriage Return or a lt LF gt Line Feed Command Syntax This section describes command syntax and structure This information must be understood in order to effectively write GPIB control programs The syntax of GPIB commands follows the rules defined in the IEEE 488 2 standard Letters Any GPIB command or query must contain all of the letters or all of the upper case letters which are shown in the command definition Upper lower case does not matter upper case is used in this manual to identify the required letters Lower case indicates optional letters If any of the optional letters are included they must all be included in the correct sequence Some examples of what works and what does not are shown below Table 3 1 Acceptable and Not Acceptable Spelling ACCEPTABLE NOT ACCEPTABLE DISP DS DISPlay or DISPLAY Displa or DISPL September 2014 35 LDC 3736 Quantum Cascade Laser Controller White Space White space is normally the space character A single white space must separate a command from its parameters or data For example Table 3 2 White Space ACCEPTABLE NOT ACCEPTABLE INSTR SEL TEC INSTR SELTEC To enhance readability one or more white spaces may be used before a comma semicolon or terminator Since the computer normally places the terminator at the end of each command string line this simply means that an extra space chara
107. riggered for each step in laser current The trigger output is always enabled NOTE The minimum time required for setpoint to be reached varies based on the type of setpoint change Care should be exercised with respect to the timing of any setpoint Commande in relation to the actual hardware function The trigger signal may be missed if the program step time is too fast A one shot trigger pulse will occur on power up of the instrument due to the states of the processor UO connections A grounded female BNC connector on the rear panel of the LDC 3736 Quantum Cascade Laser Controller is available for connecting any standard BNC terminated cable and connecting to equipment that can accept the levels produced by the LDC 3736 instrument trigger out signal Operating the Temperature Controller from the Front Panel General Guidelines for Sensor Selection and Safety Limits This section presents some guidelines to assist in selecting the optimal settings for your application Sensor Options The LDC 3736 Quantum Cascade Laser Controller can measure temperature through a variety of sensor options thermistors IC sensors IC I IC V or RTDs THERMISTOR When a thermistor sensor is selected the LDC 3736 instrument measures temperature based on a negative temperature coefficient NTC thermistor An NTC thermistor is a device whose resistance decreases as its temperature increases The controller provides a sense current 100 UA or 10 pA through t
108. ring data received E 158 String data not allowed E 160 General block data error E 161 Invalid block data received E 168 Block data not allowed E 170 Command expression error E 171 Invalid expression received E 178 Expression data not allowed E 180 General command macro error E 200 General execution error E 201 Invalid command when in local mode E 202 Settings have been lost E 203 Command is protected and cannot be called E 220 Error with parameter during execution E 221 A settings conflict has occurred E 222 Data out of range E 223 Too much data received E 224 Illegal parameter value received E 225 Execution ran out of memory E 226 List received are not of the same length E 230 Data received is corrupt or stale E 231 Data received is in a questionable state E 232 Data received is in an invalid format E 233 Data received is in an invalid version E 240 A hardware error has occurred during execution E 241 The hardware is missing E 250 A mass storage error has occurred during execution E 251 The mass storage is missing E 252 The media is missing E 253 The media is corrupt E 254 The media is full E 255 The directory is full E 256 File name not found E 257 File name error E 258 The media is protected September 2014 78 LDC 3736 Quantum Cascade Laser Controller
109. rom the following calculations First determine the intermediate values U and V where V T T Ty Ty and U Ta Tar V Then C1 and C2 can be determined by the following C1 U V C1 and C2 V C2 Replace C1 with C1 by selecting the C1 parameter and entering the new C1 value Replace C2 with C2 by selecting the C2 parameter and entering the new C2 value September 2014 92 LDC 3736 Quantum Cascade Laser Controller Appendix B Auto Tune Method The LDC 3736 Quantum Cascade Laser Controller currently uses a single auto tune method The auto tune algorithm will calculate a thermal system s appropriate PID coefficients through a mathematical PID analysis process The figure and text below describe the tuning process Measured Temperature Setpoint temperature p2 Current out Minimum Current Maximum Current Temperature Celsius Figure B 1 Tuning Process The autotune procedure requires a temperature or resistance setpoint a maximum TEC current and a minimum TEC current value to be entered in order to begin The setpoint is set using the front panel adjust section to set the TEC setpoint to the desired value The maximum and minimum TEC current are set by setting the I and I values through the limits submenu of the TEC parameter menu In the example shown a temperature setpoint above ambient is entered and maximum and minimum TEC current values are set to 2 0 and 2 0 Am
110. round 3706 Series Laser Diode Controller Common Laser Anode Photodiode Cathode Earth Ground Figure 2 1 Laser Diode Connection Configurations September 2014 12 LDC 3736 Quantum Cascade Laser Controller 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 of the LDC 3736 Quantum Cascade Laser Controller are electrically isolated from ground and each other So if a 4 pin connection is made no common connections no additional jumpers are required Figure 2 1 above shows the recommended connections and shielding for 3 pin lasers where the common connection is internal to the device A 4 pin laser should be connected with the same shielding as shown in Figure 2 1 but the common connection between the photodiode and the laser is optional Photodiode Bias The LDC 3736 provides an adjustable reverse bias of O to 5 VDC for the photodiode To set the photodiode bias to the desired value use the parameter buttons menu structure and adjustment knob Refer to the Front Panel Operation section of this chapter for further details Front Panel Operation General Operation This section describes the fundamentals of operation for the LDC 3736 Quantum Cascade Laser Controller The order of descriptions will follow the normal pro
111. rrent passed through the sensor An example of an IC I sensor is the Analog Devices AD590 This device delivers 1 uA K or approximately 298 UA at 25 C The terminal of the transducer should be connected to the Sensor pin and the terminal should be connected to Sensor The nominal slope for the AD590 is 1 UA K and the offset is nominally O uA but both can be adjusted to calibrate your particular sensor by entering the TEC parameter menu The sensor will have approximately 9 V across it at 25 C but will vary over the temperature range In IC I sensor mode the LDC 3736 has a sensor current limit of 600 WA which is approximately 325 C M warnine For IC Current sensors used with the LDC 3736 the 4 wire sensor measurements pins 7 and 8 should not be connected The use of the 4 wire sensor will cause inaccurate sensor measurements IC V SENSORS When an IC V sensor is selected the LDC 3736 instrument measures temperature based on the voltage across the sensor An example of an IC V sensor is the National Semiconductor LM335A This device delivers 10 mV K or approximately 2 98 V at 25 C The terminal of the transducer should be connected to the Sensor pin and the terminal should be connected to Sensor The nominal slope for the LM335A is 10 mV K and the offset is nominally 0 mV but both can be adjusted to calibrate your particular sensor by entering the PARAM menu The sensor will have approximately 1 mA of current thro
112. rument will apply a second current after a short time Repeat step 5 for the second current September 2014 86 LDC 3736 Quantum Cascade Laser Controller 7 Once the self calibration is completed and calibration mode is exited the calibration constants will be stored to the non volatile memory and the display will return to its previous state Photodiode Current Calibration 1 8 9 Setup an optocoupler with a forward emitter current of 40 mA or greater and a maximum collector output current of 10 mA or less in a current divider circuit with the emitter in series with a 100 Q resistor and with a 1 O 25 W resistor in parallel across the 100 Q resistor and optocoupler Connect this circuit across the laser output terminals of the LDC 3736 instrument pins 4 5 and 8 9 on the 9 pin connector Measure and record the exact resistance of a 1 O metal film resistor A 4 point probe resistance measurement is recommended Connect the 1 Ohm metal film resistor to the emitter of the optocoupler detector and connect the photodiode cathode and anode input terminals of the LDC 3736 instrument pins 6 and 7 of the 9 pin connector to the free end of the 1 Ohm metal film resistor and to the collector of the optocoupler detector respectively Connect a calibrated DMM in parallel across the 1 Ohm metal film resistor to measure the voltage across this resistor Select constant power mode operation Set the Power Limit to its maximum Navigate
113. s The PID values will be appropriate to control to set points near the setpoint used during the procedure under similar conditions to those that occurred during the autotune procedure These values can be altered through the manual PID setting section of the front panel or through remote commands to fine tune performance or to adjust for different set points and operating conditions September 2014 94 LDC 3736 Quantum Cascade Laser Controller
114. s enable register when expressed in base 2 binary format See ESR for a description of each bit in the status register along with a diagram of the reporting structure Examples ESE A response of 68 means the user request and query error bits have been enabled in the standard event status enable register 68 27 2 September 2014 50 LDC 3736 Quantum Cascade Laser Controller ESR Standard Event Status Register Query Description Determine the contents of the standard event status register Parameters None Notes Reading this register clears the contents The response is a value between 0 and 255 representing the bits of the standard event status register when expressed in base 2 binary format The event bit is set when a specific event occurs Standard Event Status Register ESR gt Logical OR 5 Bit O Operation Complete is set when all pending device operations have been finished after OPC common command has been executed Unused and always reports 0 Query Error means that data in the output has been lost or that none was available O Operation Complete 1 Request Control 2 Query Error 3 Device Dependent Error 4 Execution Error 5 Command Error 6 User Request 7 Power On To Status Byte Bit 5 lt Standard Event Status Enable Register ESE lt nrf gt ESE Device Specific Error is an error has occurred that is neither a command query or execution error
115. s the TEC voltage measurement 1 2 Calibrate the ITE current as described in the section above With the output off connect a 2 O 150 W resistor across the TEC output terminals of the LDC 3726 3746 pins 1 and 3 of the 15 pin connector or the LDC 3736 37620 pins 9 10 21 22 and 12 13 24 25 of the 25 pin connector Connect a calibrated DMM across the load resistor Navigate to the Vte Cal selection in the Calibration submenu of TEC parameter menu tree Enter the calibration mode by pressing the SET button while the Vte Cal selection is shown on the display Then press the TEC button to start the calibration process Measure the voltage using the DMM Adjust the voltage shown on the lower display to match your measured voltage by turning the ADJUST knob Then press the TEC button The instrument will apply a second current after a short time Repeat step 6 for the new voltage measurement Wait for the 7 segment display to exit the calibration mode Once the self calibration is completed and calibration mode is exited the calibration constants will be stored to the non volatile memory and the display will return to its previous state September 2014 85 LDC 3736 Quantum Cascade Laser Controller Laser Driver Current Calibration The following procedure calibrates the laser constant current source for a single range and modulation state This procedure will need to be performed for each combination of laser driver curr
116. s the currently displayed menu item or allows the user to adjust the currently displayed parameter The ADJUST knob can be used to cycle through and select or modify the following parameters Limits The Limits menu allows the user to select and modify the temperature current and sensor upper and lower limits e Temperature High Low Limits e Current Positive Negative Limits e Sensor High Low Limits Depending on the sensor selected the user can configure high and low limits for resistance current or voltage Sensor The Sensor parameter allows the user to select the type of sensor for the application Thermistor RTD IC V or IC l For more information on temperature sensors see the Sensor Options section later in this chapter The sensor type selections are e Thermistor 100 pA 10 pA Auto Ranging e RIDO mA 2 5 mA auto ranging s IC Current e IC Voltage Sensor Calibration Constants The calibration constants menu allows the user to enter sensor constants for thermistor current and voltage IC and RTD For more information see the Sensor Options later in this chapter External Fan Control Allows the user to enable or disable the external fan The user can also set the voltage applied to the external fan Analog Control Input Enables and disables the analog input feature for optimal stability if a signal is not being applied to it the analog control input should be disabled Calibration This menu allows cal
117. ser Controller September 2014 42 LDC 3736 Quantum Cascade Laser Controller Chapter 4 Command Reference This chapter is a guide to all of the device dependent commands for the LDC 3736 Quantum Cascade Laser Controller This chapter is divided into three parts Y Overview of the remote commands Y List of remote commands in alphabetical order LDC 3736 Compatible Commands Remote Command Reference Summary This section contains all of the commands for the LDC 3736 listed in alphabetical order Table 4 1 contains a list and a description of each IEEE 488 1 common command Table 4 2 contains the instrument specific commands Unless otherwise noted each of the instrument specific commands has a corresponding query without a parameter See Figure 3 3 for the command path tree structure Table 4 1 Remote Command Summary of IEEE 488 1 Common Commands COMMAND SYNTAX FUNCTION CLS Resets the Standard Event Register Status Byte and Error Queue to zero ESE lt integer gt Sets the Standard Event Status Enable Register ESE Returns the value of the Standard Event Status Enable Register ESR Returns the value of the Standard Event Status Register IDN Returns the Device Identification string OPC Generates the Operation Complete message in the Standard Event Status Register OPC Places an ASCII character 1 into the Output Queue RCL lt integer gt Used to recall a stored setup
118. sure measurement accuracy the voltage across the thermistor must not exceed DV e TO improve control responsiveness and accuracy the thermistor voltage variations that result when the load temperature deviates from the setpoint must be as large as possible The importance of maximizing voltage variation is shown in Figure 2 4 which shows resistance as a function of temperature for a thermistor The values shown were selected for simplicity in this example and may not reflect real thermistor values In the example shown in Figure 2 4 the thermistor resistance is 25 kQ at 20 C Deviations of one degree at 20 C cause a resistance variation of about 2 KQ If using the 10 pA setting there is 20 mV of feedback to the control circuit Using the 100 pA setting provides 200 mV of feedback The larger feedback signal means that the temperature is more precisely controlled Notice also that the lower slope of the curve at the higher temperatures results in a smaller feedback signal It may be necessary if you are controlling to higher temperatures to use a thermistor with a different curve September 2014 23 LDC 3736 Quantum Cascade Laser Controller Vth 10uA Mib 100 uA Resistance 0 5 V 0 4 V 0 3 V 20 C 40 C 60 C 80 C 100 C Figure 2 4 Example Thermistor Resistance vs Temperature IC SENSORS When an IC I sensor is selected the LDC 3736 Quantum Cascade Laser Controller measures temperature based on the cu
119. t settings SYSTem VERSion Report currently installed firmware version September 2014 49 LDC 3736 Quantum Cascade Laser Controller Command Reference The following pages contain a reference for common commands of the LDC 3736 Quantum Cascade Laser Controller CLS Clear Status Description Clears all status event registers the event filter the status register SRQ bit the OPC bit and the error queue Notes Useful to clear registers before enabling service requests SRQ Examples CLS ESE lt integer gt Standard Event Status Enable Description Sets the bits in the standard event status enable register Parameters The value must be between 0 and 255 Notes The integer sent as a parameter is expressed in binary form when an event occurs in the standard event status register that matches the corresponding bit in the standard event status enable register bit 5 will be enabled in the status byte register See ESR for a description of each bit in the status register along with a diagram of the reporting structure Examples ESE 40 Sets the standard event status enable register to enable bit 5 of the status byte register if a device dependent error or a command error occurs 40 274 2 ESE Event Status Enable Query Description Determine the contents of the standard event status enable register Parameters None Notes The response is a value between 0 and 255 representing the bits of the standard event statu
120. tember 2014 71 LDC 3736 Quantum Cascade Laser Controller Troubleshooting Guide This section lists some common problems and corrective actions In the event that the corrective action does not resolve problem please contact ILX Lightwave For a comprehensive list of frequently asked questions see the ILX Lightwave website or contact ILX Lightwave Customer Service see Comments Suggestions and Problems on page viii for contact information GENERAL The instrument does not power up Check the power cord to make sure that it is securely connected and check the wall outlet by connecting to a known operational device There are no user serviceable fuses on this device but there are several internal fuses Contact customer support at ILX Lightwave The instrument reads Internal Error code 516 is the internal communication error indication Communication Error that the LDC 3736 is not functioning correctly The instrument must be returned to ILX Lightwave if this error occurs Slow or unexpected response to remote Check that no two devices are set to the same GPIB commands address Make sure that there are less than 15 devices on the bus Check the configuration of your GPIB controller card or COM port Specifically note the information regarding the terminating character Check that total GPIB cable length is less than 20 meters 65 feet Remove all other instruments from the bus to isolate the LDC 3736 If this corrects th
121. th at rating Temperature PC to 40 mid scale output Storage Temperature 30 C to 70 C 10 Responsivity value is user defined and is used to calculate the optical power Humidity lt 85 relative non condensing 11 Four wire voltage measurement at the load Voltage measurement accuracy while driving calibration load Accuracy is dependent Compliance CE upon load and cable used 1 Output de rating 0 3 Volts and 0 04 Amps per input Volt AC below 100 VAC to a minimum of 90 VAC September 2014 Based on resolution of digital to analog converts used in circuit 4 LDC 3736 Quantum Cascade Laser Controller TEMPERATURE CONTROL TEC OUTPUT Output Type Bi directional linear LDC 3736 Isolation Floating with respect to earth ground Temperature Control Range Keen Sjon 8 00A to 8 00A Thermistor Sensor 100 C to 200 C Sa Di A 0 01 A j IC Sensor 100 C to 150 C D Ka RTD Sensor 100 C to 200 C Current Limit Temperature Setpoint and Measurement Dec Ae Kee Repeatability and Accuracy Volta lt r 7 di 0C 0 001 C 0 01 C es 6 00V v 25 C 40 002 C 0 04 C Loh si PA NOR 50 C 0 007 C 0 15 C jeere A N Te Compliance Voltage BH Temperature Stability Maxi Outp Sau 1 Hour 0 002 C dei se 5 24 Hours 0 003 C Current Noise and Ripple lt 2 5 mA rms TEMPERATURE SENSOR AUXILIARY LO SPECIFICATIONS Types Input ta FR 5V to 5V Thermistor NTC 2 wire age Fangs RA IC V Semiconductor IC Sensor LM 33
122. ti static protective caps that were shipped with the instrument Place the instrument in the original packing container with at least 3 inches 7 5 cm of compressible packaging material Shipping damage is not covered by this warranty Secure the packing box with fiber reinforced strapping tape or metal bands Send the instrument transportation pre paid to ILX Lightwave Clearly write the return merchandise 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 September 2014 viii LDC 3736 Quantum Cascade Laser Controller 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 questi
123. to non volatile memory Parameters A value from 1 10 Notes The SAV operation saves the contents of everything affected by the RST command Itis not necessary to save the current setup for next power on The current setup is automatically stored and recall at next power on Use RCL lt bin gt to restore the saved configuration Examples SAV 3 The current instrument configuration is stored in memory bin 3 SRE lt integer gt Service Request Enable Command Description Sets the service request enable register bits Parameters A value in the range of O to 255 Notes The integer sent as a parameter when expressed in binary format each bit represents a bit in the service request enable register A bit value of one indicates an enabled condition A bit value of zero indicates a disabled condition Bit 6 will be ignored Setting the service request enable register allows the programmer to select which summary messages in the status byte register may cause service requests Each bit in the service request enable register corresponds to a bit in the status byte register A service request is generated when a bit in either the service request enable register or the status byte register transitions from zero to one and the corresponding bit in the other register is either set to one or transitions from zero to one at the same time Status Byte Register SERVICE STB REQUEST e SS i l i LOGICAL OR E ad
124. 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 September 2014 9 LDC 3736 Quantum Cascade Laser Controller A CAUTION The interlock terminals on the LASER connector pins 1 and 2 must be kept isolated from all other connections including earth ground M warnine The Current Source output terminals of the LDC 3736 Quantum Cascade Laser Controller Laser Anode and Laser Cathode should never be shorted together or loaded with less than 0 1 O Doing so may result in damage to the instrument Temperature Control Output A 25 pin D sub connector is located on the back panel of the instrument The connections are shown below September 2014 LDC 3736 1 9000000000000 AN Ae PIN NUMBER CONNECTION 1 Sensor Sense Terminal 2 Sensor Sense Terminal 3 Fan 4 N C 5 N C 6 Sensor TE Module Shield 7 TE Module Sense Terminal 8 TE Module Sense Terminal 9 TE Module 10 TE Module 11 N C 12 TE Module 13 TE Module 14 Sensor 15 Sensor 16 Fan 17 Cable ID 1 18 Cable ID 2 19 N C 20 N C 21 TE Module 22 TE Module 23 N C 24 TE Module 25 TE Module 10 LDC 3736 Quantum Cascade Laser Controller TEC Grounding Considerations The TEC
125. to the MDI selection in the Laser Calibration submenu of laser parameter menu tree Select the MDI calibration mode by pressing the SET button while the MDI selection is displayed Then press the LAS button to start the calibration procedure Wait for the photodiode current to ramp up and settle then calculate the actual photodiode current output by using Ohm s Law I V R Where V is the accurately measured voltage across the resistor with a precision multimeter and R is the accurately measured load resistance Turn the ADJUST knob until the display shows the value of the photodiode current measurement as calculated from step 6 Then press the LAS button The instrument will ramp to a new setpoint Repeat step 7 for the newly calculated photodiode current at this setpoint 10 Wait for the 7 segment display to exit the calibration mode Once the self calibration is completed the calibration constants will be stored to the non volatile memory and the display will return to its previous state September 2014 87 LDC 3736 Quantum Cascade Laser Controller September 2014 88 LDC 3736 Quantum Cascade Laser Controller Appendix A AD590 and LM335 Sensor Calibration The LDC 3736 Quantum Cascade Laser Controller uses two constants slope and offset for calibrating linear IC thermal sensing devices such as the AD590 and the LM335 Offset is used as the linear or zero offset value and the slope is used as the slope or gain adjustme
126. troller TEMPERATURE CONTROLLER The instrument reads Sensor Open Confirm the appropriate sensor has been selected under the PARAM menu Check the cable connections to the sensor If the problem persists contact customer support at ILX Lightwave Power on but temperature is not If there is a SENSOR OPEN indication Error code 505 controlled or is unstable check the sensor connections pins 14 15 Check that the proper sensor current range is selected Check that the appropriate coefficients have been set for your sensor Refer to the Sensor Options section under General Operating Procedures in Chapter 2 Check that the P and D constants are optimized for your thermal load and that the current limit value is not too low If the problem persists contact customer support at ILX Lightwave IC Current sensor value is not changing Insure the 4 wire sensor voltage measurement pins 1 and on the LDC 3736 2 are not connected to the sensor Inaccurate sensor TEC voltage or TEC Insure the 4 wire TEC sensor connections pins 7 and 8 are current measurement on the LDC 3736 connected For thermistor or RTD sensors insure the 4 wire sensor connections pins 1 and 2 are connected September 2014 75 LDC 3736 Quantum Cascade Laser Controller Error Messages Error messages may appear on the LDC 3736 display when error conditions occur in the instrument In remote operation use SYST ERR ALL to read the current error l
127. ugh it at all times In IC V sensor mode the LDC 3736 instrument has a sensor voltage limit of 6 V which is approximately 325 C September 2014 24 LDC 3736 Quantum Cascade Laser Controller RTD SENSORS When an RTD sensor is selected the LDC 3736 measures temperature based on the resistance of the sensor An example of an RTD sensor is the Xian Diamond USA T2001SDL This device has a positive slope and a nominal resistance at 0 C of 100 ohms Two wire RTDs should be connected across the Sensor and Sensor pins pins 7 and 8 The resistance versus temperature function for typical platinum RTDs is accurately modeled by the Callendar Van Dusen equation as shown below Rr Ro 1 AT BT 100CT CT where Ro Resistance Q at 0 C Rr Resistance Q at temperature T C T Temperature in C The A B and C are derived from resistance measurements at O C Ro 100 C R100 and 260 C R250 and are defined as follows A a a d 100 B a 5 100 Creo a 8 100 where a Rigo Ro 100 Ro RB Constant for T lt 0 C zero otherwise 6 Ro 1 a 260 Rogo 4 16 Ro a For temperatures greater than 0 C the LDC 3736 Quantum Cascade Laser Controller derives the temperature by solving the following quadratic equation RA Ro2A 4R9B Ro Rr E 2R9B These sensor coefficients A B C and Ro are required for the LDC 3736 instrument to accurately report the te
128. ured current in Amps Notes This is the same as CALibrate MDI STARt and CALibrate MDI DATA above there are two versions for user flexibility CALibrate RTD1000UA STARt CALibrate RTD1000UA DATA lt nrf gt Description Begins Takes data for the 1 mA RTD resistance calibration procedure Parameters DATA a number representing the measured resistance in Ohms CALibrate RTD2500UA STARt CALibrate RTD2500UA DATA lt nrf gt Description Begins Takes data for the 2 5 mA RTD resistance calibration procedure Parameters DATA a number representing the measured resistance in Ohms September 2014 58 LDC 3736 Quantum Cascade Laser Controller CALibrate SENSORV STARt CALibrate SENSORV DATA lt nrf gt Description Parameters DATA a number representing the measured voltage in Volts CALibrate VALues lt string gt lt nrf gt lt nrf gt CALibrate VALues lt string gt Description Parameters Notes September 2014 slope the second parameter is the slope constant to be set offset the third parameter is the offset constant to be set Acceptable strings for first parameter CURRent 1 SETPoint LOW BYPass CURRent 1 SETPoint LOW CURRent 1 SETPoint MEDium BYPass CURRent 1 SETPoint MEDium CURRent 1 SETPoint HIGH BY Pass CURRent 1 SETPoint HIGH CURRent 1 LIMitLOW CURRent 1 LIMit MEDium CURRent 1 LIMit HIGH VOLTage LIMit POWer LIMit CURRent 1 MEASure LOW CURRent
129. ut of the laser with a calibrated detector Second measure the corresponding photodiode current either with the LDC 3736 or a calibrated current meter The calibrated PD responsivity is calculated by dividing the photodiode current by the output power uA mW Under the ADJUST section press the LASER soft button and use the knob to adjust the output power to your desired output Press the ON soft button under LASER MODE It is advised when using a new laser or connection to the laser to set the output to zero prior to enabling the output Once the output is enabled slowly ramp the current to your desired output September 2014 21 LDC 3736 Quantum Cascade Laser Controller 8 The user can display measured voltage photodiode current photodiode power set point and measured current in either the left or right side of the LASER display by pressing the LEFT or RIGHT display soft buttons under the LASER display Using the LDC 3736 Controller s Trigger Output Function For applications where you need to synchronously initiate a measurement task for a remote instrument with the LDC 3736 the controller offers a TTL level trigger output signal The trigger pulse is initiated with any change in setpoint 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 V curve is generated For programmed steps in laser current a light measurement can be t
130. ut port on the front of the instrument make sure that the Modulation State is set to the OFF condition by pressing the Enable button until the ENABLE LED is unlit September 2014 17 LDC 3736 Quantum Cascade Laser Controller Current Control Mode SELECT Button Right Selects constant current or constant power mode The selected mode is indicated by an illuminated LED The output is disabled when the control mode is changed ON Button Right Enables and disables the current output An enabled output is indicated by an illumined LED above the ON button right A disabled output is indicated by an unlit LED above the ON button right e CURRENT Controls the LDC 3706 current source to constant operating current e POWER Controls the LDC 3706 to a constant power or constant photodiode current LASER RANGE Button Right Selects between the output ranges of the LDC 3736 LDC 3736 Range 1 0 1A Range 2 0 2A Range 3 0 4A Display The two large 7 segment VFD displays show the measured value in the selected operating mode When the setpoint is being adjusted the 7 segment LED display will show set after the dimension and revert back to reporting the measured value after the three second timeout The dot matrix display at the bottom of the screen cycles through available measurements and the mode setpoint The available measurement and setpoint parameters are listed under General Operation Procedur
131. utput connector of the LDC 3726 3746 pins 7 and 8 or the 25 pin output connector of the LDC 3736 37620 pins 14 and 15 3 Enter the sensor calibration mode by navigating to the RTD1mACal selection in the Sensor Cal area of the Calibration submenu of TEC parameter menu tree 4 Select the appropriate RTD calibration selection by pressing the SET button when the title for that calibration procedure is shown on the display then press the TEC button in order to enable the sensor current 5 Turn the ADJUST knob until the display indicates the same resistance you recorded for the 300 Q resistor Press the TEC button 6 Connect the 1200 O resistor to the sensor pins 7 Turn the ADJUST knob until the display indicates the same resistance you recorded for the 1200 Q resistor Press the TEC button September 2014 83 LDC 3736 Quantum Cascade Laser Controller Wait for the 7 segment display to exit the calibration mode and reflect the entered sensor resistance setpoint Once the calibration is completed the calibration constants will be stored to the non volatile memory and the display will return to its previous state 2 5 mA RTD 1 2 Measure and record the exact resistance of a 60 O and 240 O metal film resistor A 4 point probe resistance measurement is recommended Connect the 60 Q resistor to the sensor pins of the 15 pin output connector of the LDC 3726 3746 pins 7 and 8 or the 25 pin output connector of the LDC 3736 3762
132. value by selecting the offset parameter and entering the offset new value September 2014 91 LDC 3736 Quantum Cascade Laser Controller Two Point Calibration Method This procedure will work for any linear IC temperature sensor The accuracy of this procedure depends on the accuracy of the known temperatures externally measured It is used to determine the zero offset of the device and the gain offset slope 1 Allow the LDC 3736 to warm up for at least one hour Set the sensor to the desired sensor type and RECALL the constants for the particular device to be calibrated Select the C1 parameter Read and record the value of C1 Select the C2 parameter Read and record the value of C2 Place the sensor at an accurately known and stable temperature Ta1 Connect the sensor to pins 7 and 8 of the LDC 3726 3746 15 pin connector or to pins 14 and 15 of the LDC 3736 37620 25 pin connector Set the LDC 3706 Series instrument for normal constant temperature T mode operation Allow the LDC 3706 Series instrument to stabilize at the known temperature Ta1 and read the displayed temperature T Record these values Repeat Step 3 for another known temperature T and the corresponding displayed temperature T The two known temperatures should at the bounds of the intended operating range The smaller of the two is intended operating range the better the calibration over that same range Determine the new value of C1 C1 and C2 C2_ f
133. values The information needed is the time it takes for a heating and cooling cycle to complete the maximum temperature reached during a cycle and the minimum temperature reached during a cycle For the fourth cycle in the graph above shown between point 5 and point 8 the time from point 5 to point 8 will be recorded to get a cycle period measurement The maximum temperature point 6 on the graph and minimum temperature point 7 on the graph will also be recorded These three values will be recorded for the last 7 cycles of the procedure After 10 total cycles are completed point 9 on the graph the output is disabled and the PID values are calculated To calculate the PID values first the measured amplitude of the cycle is calculated by taking the maximum measured temperature minus the minimum measured temperature for each cycle Then the average of the seven measured amplitudes and the seven measured cycle periods will be calculated Using these averages and the maximum and minimum TEC current settings the PID values are calculated as follows Driving Amplitude maximum TEC current minimum TEC current Amplitude Ratio 4 Driving Amplitude x Average Measured Amplitude P 0 6 Amplitude Ratio 1 0 Average Period 2 0 D Average Period 32 0 The PID values are then saved into the manual PID values and the instrument is ready to control to the given setpoint The PID tuning process typically takes 5 to 10 minute
134. vices 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 while listeners accept data A system can consist of simply a talker September 2014 31 LDC 3736 Quantum Cascade Laser Controller and listener as in a system comprised of a meter connected to a data logger 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 may also designate itself as a listener when it needs to 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 computer to another In a multiple controller system there can be one System Controller capable of asserting control becoming CIC GPIB Cable Connections Standard GPIB connectors can be connected together stacked allowing the system to be configured linearly or in a star configuration mm Linear Configuration Star Configuration Figure 3 1 GPIB Cable Connection September 2014 32 LDC 3736 Quantum Cascade Laser Controller The GPIB Connector The standard GPIB connector consists of 16 signal lines in a 24 pin stackable connector The extra pins are used to

User`s Guide - Newport Corporation

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