Stanford Research Systems SR620, Manual

Page: 89 / 124

Calibration Procedure 73
SR620 Universal Time Interval Counter
1) Attach the voltmeter to D/A #0. Set D/A #0 to
10V. Set calbyte 18 to 1.
2) Measure the output voltage. Gain factor =
10.0/V.
3) Calculate calbyte 18 as follows:
a) If the gain is less than 1, multiply the gain
factor by 65536 and round even.
b) If the gain is greater than or equal to 1,
multiply the gain factor by 65536 and
round odd.
4) Repeat 1-3 with output 1 to get calbyte 19.
DVM Input Calibration
1) Attach a stable dc source to DVM input 0 and
to the voltmeter.
2) Set the DVM 0 input range to 20V.
3) Set the dc source to 0.
4) Adjust calbyte 20 until the DVM 0 reading and
the voltmeter reading agree.
5) Set the dc source to about 18 V.
6) Adjust calbyte 24 until the DVM 0 reading and
the voltmeter agree.
7) Set the DVM 0 input range to 2V and the dc
source to 0.
8) Adjust calbyte 22 until the DVM 0 reading and
the voltmeter agree.
9) Set the dc source for about 1.8V.
10) Adjust calbyte 26 until the DVM 0 reading and
the voltmeter agree.
11)
Repeat 1-10 for DVM input 1 to get values for
calbytes 21,25,23, and 27.