Recommended Equipment, Dmm | Lightwave Communications LDX-3232

C H A P T E R 6

CALIBRATION AND TR OU BLESHOOTING

Recommended Equipment

Finally, the LDX-3232 Current Source should be allowed to warm up for at least one hour before calibration.

Recommended Equipment

Recommended test equipment for calibrating the LDX-3232 Current Source is listed in Table 6.1. Equipment other than that shown in the table may be used if the specifications meet or exceed those listed.

Table 6.1 Recommended Test Equipment

Description	Manufacturer/Model	Specification
DMM	HP 3457A	DC Amps (@ 1.0 A): ±0.02%
		Resistance (@ 10 Ω): ±0.02%
		0.1 µA or 0.1 mV resolution

It will be necessary to connect various loads and circuits to the outputs of each current source for the calibration procedure. A schematic is shown in Figure 6.1 for the photodiode calibration circuit with the required components listed in Table 6.2. Also, the devices required for other calibration loads are listed in Table 6.2.

Table 6.2 Required Calibration Components

Laser Current Source Calibration

Current Source Calibration, all models	10	Ω, 20 W resistor, low TCR

Voltage Measurement Calibration	15	Ω, 5 W resistor, low TCR

PD Monitor Calibration (See Schematic in Figure 6.1)

PD Calibration Circuit
R1		49 Ω resistor, 1%, 1/4 W
R2		100 Ω resistor, 1%, 1/4 W
R4		1.0 MΩ resistor, 1%, 1/4 W
R3		5 Ω, 1%, 10W
U1		TIL 117 opto isolator

90 LDX-3232

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Lightwave Communications LDX-3232 manual Recommended Equipment, Description Manufacturer/Model Specification, Dmm

Contents

User’s Guide Page Table of Contents Remote Operation Command Reference Iv LDX-3232 List of Figures Vi LDX-3232 List of Tables Viii LDX-3232 Safety Information and the Manual General Safety Considerations Safety Symbols Safety Marking Symbols Warranty Claims for Shipping Damage Description of the problem Comments, Suggestions, and ProblemsModel Number Serial Number End-User Name Company Phone Fax Xiv LDX-3232 Introduction and Specifications Product Overview Initial Inspection Installing Your LDX-3232 High Compliance Current SourceAC Line Power Requirements Grounding Requirements Gpib Address Gpib ConnectorTilt-Foot Adjustment Operating the LDX-3232 Precision Current Source LDX-3232 Front View Maintenance Specifications TTL Type Pulse Width Delay13 µs 12 ms Available Options and Accessories Description Model Number Applying Power to Your LDX-3232 Power On Sequence Connecting to the Laser Power On State Common Laser Cathode Photodiode Anode Back Panel LD Connector Interlock Connections Photodiode Connections Setting the PD BiasGrounding Considerations Front Panel Operation Operating a Laser in Constant Current I ModeDisplay Setting Up the Precision Current Source E R a T I O N Operating a Laser in Constant Power P Mode Entering Photodiode Responsivity Values Method to calculate the responsivity is suggested below Error Indicators LDX-3232 Error Indicators Error Indicators LDX-3232 Reading the Gpib Address Changing the Gpib Address Command Syntax LDX-3232 Current Source Command SetChanging Operation from Local to Remote OFF OLD NEW True False SET Reset LASLDI? Command Paths LDX-3232 Command Path Structure IEEE488.2 Command Commands None LDX-3232 Frequently Used CommandsLIM Event and Condition Registers Status ReportingOperation Complete Definition LDX-3232 Status Reporting Schematic Diagram Disabled 10 N/A Enabled 11 N/A 12 N/A 13 N/A 14 N/A 15 N/A Output Off Register LASerENABleOUTOFF nrf LASerENABleOUTOFF? Command Timing and Completion Error Messages Error Code Classifications Response Message Mode Used to enter the laser current calibration mode Used to create a delay in the execution of furtherCommands Used to enter the laser voltage calibration mode Sets the enable register for Laser conditions Returns status of photodiode monitor power displayEnables Laser display to show parameter values Returns the value of the LAS conditions enable register Used to enable/disable the front panel modulation input Used to return the optical power from monitorUsed to set the constant optical power setpoint, if Or P optical power Returns the elapsed time since the timer was last reset Returns the status of the Term commandPowered up Used to return the Laser setpoint tolerance value LDX-3232 Device-Dependent Commands Command Description Format LDX-3232 Device-Dependent Command Reference Delay LASerCALMD ERRors?Calmd LAS Calpd Responsivity CAL PD parameter setting Syntax Diagram LASerCALMD? LASerCALLDI Selected. This procedure is outlined in ChapterCalibration for that bandwidth LDI LAS CAL LASerCALLDI?LASerCALLDV LAS CAL LDV LASerCALLDV? True measured value. This procedure is outlined in ChapterLASerCALMDI MDI LASerCALMDI?LASerCOND? LAS CAL IPD LASerDEC LAS DIS LASerDISplayLASerDISplay? LASDIS? Lasdisldi LASerDISplayLDILASerDISplayLDI? LDI LASerDISplayLDV? Voltage measurement Syntax DiagramLASerDISplayLDV LASDISLDV? LAS DIS MDI LASerDISplayMDILASerDISplayMDI? LAS DIS IPD PPD LASerDISplayMDPLASerDISplayMDP? LAS DIS MDP LAS DIS Param LASerDISplayPARAMLASerDISplaySET LAS DIS SET LASerDISplaySET? LASerENABleCONDLASDISPLAYSET? Bit LASerENABleCOND?LAS Enab Cond Action enables the Laser status event register so that LASerENABleEVEntAn nrf value whose sum represents the bits that are enabled Lasenabevent LASerENABleEVEnt? LAS Enab EVE LASerENABleOUTOFF LASerENABleOUTOFF? LAS Enab Outoff LASerEVEnt? LASerENABleEVEnt commandCommand while the condition status is constantly changing LAS EVE LASerINC Function for the Laser output LASerLDI? This measurement is updated approximately once every 600 msLASerLDI LAS LDI For LDV calibration LASerLDVLASerLDV? LAS LDV Limit in use depends on the Laser output range selection LASerLIMitI2LASerLIMitI2? LAS LIM LASerLIMitI4? Displayed, and then releasing the SET switchLASerLIMitI4 LASLIMI4? LASerLIMitMDP? LASerLIMitMDPMDP LAS LIM LASerLIMitV LASerLIMitV? MDI LAS IPD LASerMDILASerMDI? MDP P PD setpoint would be used LASerMDLN? LASerMDLNLAS Mdln LASerMDP? LASerMDPMDP LAS LASerMODE? LAS ModeLAS Mode Ihbw LASerMODEIHBW LASerMODEMDP LAS Mode MDPLASerMODEILBW Lasmodeilbw LASerOUTput? LASerOUTputLAS OUT LAS RAN LASerRANgeLASerRANge? LASRAN? LASerSETLDI? Where the response is the constant I setpoint value, in mA30 µA, for use in constant P mode with Calpd = LASerSETMDI? LASerSTEP Where the response is the constand PPD setpoint, in mWLASerSETMDP? 100 µA LASerTOLerance LASerTOLerance commandLASerSTEP? LAS TOL Second is the time window, in seconds LASerTOLerance?MESsage MES MESsage? RADix RAD Term 0 command is sent or the LDX-3232 is powered offRADix? Means hexadecimal, and OCT means octal Time clock is independent of the Timer clock LDX-3232 was last powered upTime Last TIMER? query is returned Since the last TIMER? query was issuedTimer Seconds since the last TIMER? query was issued Functions and Features Saving and Recalling from the Front Panel Using the Laser Compliance Voltage Adjustment Saving and Recalling Under Remote Operation Using the LDX-3232 Current Source’s Trigger Function LDX-3232 Rear Panel Modulating the Laser Current Source BNC Interlock Usage Example Modulating the Laser Current Source Functions and Features Calibration and Troubleshooting Calibration Overview Recommended Equipment Description Manufacturer/Model SpecificationDMM Range Local Calibration of the LDX-3232 Current SourceCurrent Source Calibration Current Limit IPD Current Calibration Set equal to zero Constant powerCAL PD IPD Setpoint 2000 mA Laser ModeLaser Forward Voltage Measurement Calibration Set to FS full scale of range Remote Calibration of the LDX-3232 Current Source Gpib CommandLimit Lasldi nrf value command IPD Setpoint Function State Gpib Command EEPROM, Lllll will be displayed on the display the laser Troubleshooting GuideGeneral Current source must be recalibrated Feature can be defeated via the Lasenableoutoff Command 101 Response Message