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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.
The current source output must be on in order to enter the LASER I calibration mode.
Enter the LAS:OUTPUT ON command to turn the current source output on.
d.
Enter the LASER I calibration mode by issuing the LAS:CAL:LDI command. The
display will indicate a current in mA.
e.
Input the first actual (measured) output current (as an <nrf value>) via the
LAS:LDI <nrf value> command.
If this value is to be measured and entered remotely via a remote controlled DMM, for
example, the measured value of the current should not be entered until the
LDX-32420 Current Source is ready to receive it. The Current Source will be ready to
receive the new measured value when, after a LAS:CAL:LDI? query is sent, the
response from the Current Source is "1".
f.
Once the newly measured I value is entered via the LAS:LDI command, the Current
Source will apply a new current equal to about 25% of the previous set current.
g.
Input the second actual (measured) output current (as an <nrf value>) as in
Step e.
h.
Once the second actual I value is entered via the LAS:LDI command, the new
calibration constants will be calculated and stored into non-volatile memory. In low
bandwidth calibration mode, the LDX-32420 Current Source will also perform current
limit calibration as indicated by the CURRENT LIMIT LED flashing. The OPC? query
may be used (after the LAS:LDI value is sent) to determine when the calibration is
completed. Or, wait about two seconds before continuing with other commands.
i.
Turn the current source output off. Change the Mode to I
constant current mode) with the LAS:IHBW command. Repeat the calibration
procedure as described above.
Remote Calibration of the LDX-32420 Current Source
C H A P T E R
(high bandwidth
HBW
LDX-32420
6
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Troubleshooting
