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76
Chapter 7
7.2.5
Local Operation I
This procedure calibrates the feedback circuits for constant I
modes. The user enters the actual value of the current, as measured by an external
DMM. The 6000 then automatically calibrates the laser feedback circuits. MOPA
modules have photodiode feedback circuits on channel B only.
The I
value for the R2 resister that matches the maximum drive current of the laser diode
module.
D Cathode
D Anode
D Cathode
D Anode
the calibration mode and then process the command(s).
The *OPC? query may be used to determine when the calibration is
completed.
The operation complete flag (bit 0 of the Standard Event Status
Register) may be used to trigger an interrupt. This type of interrupt is
enabled by setting bit 0 of the Service Request Enable register and
using the *OPC command.
PD
calibration circuit is diagrammed below. Use Table 10 above to select a
PD
9 Pin D-Sub
4,5
8,9
6
7
A
V
Ammeter
Voltmeter
Ipd Current
Figure 34 - I
a.
With the laser output off, connect a calibrated ammeter to the PD
Anode output of the module and connect the circuit of Figure 34 to the
laser and PD outputs.
If a calibrated ammeter (with 0.1 µA resolution) is not available, place a
calibrated DMM (with 0.1 mV resolution) to measure the voltage
across the resistor, R3, as shown in Figure 34. Calculate the current in
the following steps by using Ohm's Law:
Calibration
Current Calibration
R3
R1
100
100
NEC PS2501-1
1
4
2
3
Calibration Circuit
PD
I = V / R
and constant P
PD
R2
PD
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