Ipd Current Calibration - ILX Lightwave LDC-3926339 User Manual

IPD Current Calibration

This procedure is for calibrating the laser I
circuits. The internal calibration procedure sets the current to two values; you
must enter the resulting I
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3c
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C A L I B R A T I O N A N D T R O U B L E S H O O T I N G
current at both of these points.
PD
With the output off, connect the IPD calibration circuit, Figure 5.1 on page 68, to the laser
connector.
Determine R4 resistance with 4-wire resistance measurement. Connect DMM across R4.
Press MAIN to enter the IPD calibration mode.
Press the Sys. Config softkey, then the Cal. softkey.
Press the Cal LAS softkey.
Press the IPD Cal softkey. The IPD calibration screen appears.
Press the Start softkey. The internal calibration procedure turns on the output and drives
the LD current until the PD current is approximately 20% of full range. Allow the current to
settle for at least 10 seconds.
Using a DMM, measure the voltage across R4. Calculate actual photo diode current
(I=E/R) and enter the value (in µA) into the IPDReal field on the screen and press ENTER.
Do not enter more than seven characters, including the decimal point. The internal
calibration procedure drives the LD current until the PD current is approximately 60% of
full range. Allow the current to settle for at least 10 seconds.
Using a DMM, measure the voltage across R4. Calcualte the actual photodiode current
(I=E/R) and enter the value (in µA) into the highlighted IPDReal field on the screen and
press ENTER.
The internal calibration procedure calibrates the I
screen then displays a message indicating that the calibration has finished.
Local Calibration
(photodiode monitor) measurement
PD
current measurement circuit. The
PD
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C H A P T E R
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LDC-3926339