Ipd Current Calibration - ILX Lightwave LDX-32420 User Manual

6
C H A P T E R
I
PD
The following procedure is for calibrating the LASER I
and measurement. This procedure calibrates the feedback circuits for constant
I
PD
user enters the actual value of the monitor current, measured with a DMM. The
LDX-32420 Series Current Source then automatically calibrates the current
measurement circuits.
Configure the Current Source in the following manner for the I
calibration:
Function
MODE
RANGE
CAL PD
CURRENT LIMIT
I
PD
*
For this test, it is recommended that the current through the transducer primary only passes through once.
76
 LDX-32420
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
Calibration of the LDX-32420 Current Source
Current Calibration
and constant P modes. When these values are reached and are stable, the
PD
SETPOINT *
a. With the LASER output off, connect the secondary of the current transducer such
that it first passes through the ammeter portion of the DMM and then into the PD
anode. Connect PD cathode to transducer common. The DMM will now be able to
directly measure PD current.
b. Press the (MODE) ON switch to turn the current source output on. Verify proper
operation, i.e. the I
unit should not be in current limit.
c. Press the (GPIB) LOCAL and FINE switches at the same time to place the Current
Source in its I Current Calibration mode.
PD
After a few seconds the display will show the I
d. After the value on the display is stable (has not changed by more than one digit for
several seconds) the LDX-32420 Current Source is ready for the actual I
be entered.
Press and hold in the (PARAMETER) SET switch and turn the adjust knob until the
display shows the actual monitor current, as shown on the DMM (or the calculated
I value from Step a).
PD
e. Release the (PARAMETER) SET switch to store the first calibration value. The
Current Source will then set the second calibration current, approximately one-fourth
(1/4) of the original current. (For example, if the first calibration setpoint was 4000 µA,
the second setpoint will be about 1000 µA.)
f. Press and hold in the (PARAMETER) SET switch and turn the adjust knob until the
display indicates the actual current as measured by the ammeter or as calculated.
State
P (constant power)
LOW
set equal to zero
90% of FS (full scale of range)
80% of FS
measurement (via DMM) and setpoint should be close, and the
PD
(PD monitor) setpoint
PD
Current
PD
setpoint value.
PD
value to
PD