Current Source Calibration - ILX Lightwave LDX-32420 User Manual

Current Source Calibration

The following procedure is for calibrating each range of the current source.
Calibration must be performed on both bandwidth modes. A total of four
calibrations will be performed on the current source. Start with the low range, low
bandwidth mode. Configure the Laser Current Source in the following state:
Function
MODE
RANGE
CURRENT LIMIT
SETPOINT
01_10
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
a. Connect the secondary current from the transducer to the DMM to measure current.
b. Configure the multimeter to measure current. You will be calculating the actual laser
current by the relationship:
I = I x CTR / N
actual measured
- where CTR is the current transfer ratio of the transducer and N is the number of
times the current from the LDX-32420 passes through the transducer.
c. Press the (MODE) ON switch to turn the current source output on. The output must
be on in order to enter the LASER I calibration mode.
d. Enter the LASER I calibration mode by pushing the (GPIB) LOCAL and (DISPLAY)
SELECT switches at the same time. The display will blank and the Current Source
will drive the current output to the setpoint and the Display will indicate output current
in mA.
e. Calculate the actual current through the transducer as described in step b. Press
and hold in the (PARAMETER) SET switch and turn the adjust knob until the display
indicates the calculated actual current.
f. Release the (PARAMETER) SET switch. After the (PARAMETER) SET switch is
released, the Current Source will drive the current output to about 25% of the first
calibration setpoint.
g. Calculate the measured current again through the transducer.
h. Press and hold in the (PARAMETER) SET switch and turn the adjust knob until the
display indicates the actual current as calculated in step g.
i. Release the (PARAMETER) SET switch to accept the second calibration point. After
the (PARAMETER) SET switch is released, the Current Source will calculate the
calibration constants and store them to nonvolatile memory. In low bandwidth
calibration mode, the LDX-32420 Series Current Source will also perform current
limit calibration, indicated by the CURRENT LIMIT LED flashing.
j. Turn the current source output off. Change the Mode to I
constant current mode). Repeat the calibration procedure as described above.
k. Change the output range to high range and repeat the calibration procedure as
described above.
Calibration of the LDX-32420 Current Source
State
I (constant current low bandwidth)
LOW
90% of FS (full scale of range)
80% of FS
C H A P T E R
(high bandwidth
HBW
LDX-32420
6
75
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