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4.0 Field Calibration and Test
Calibration:
The Model 1250B should not require field calibration. However, there
are provisions in the menu to facilitate Analog Output Calibration. The analog output may be
adjusted in the field. A calibrated multi-meter should be used to measure the output signal
during calibration.
To enable analog calibration, select the
OP 30, CAL
menu command and choose the
“On” mode. If you are using the RS-232 serial port, use the
ANACAL
command. The
analog output may be forced to LOW, MID, and HIGH output signal states.
If menu commands are being used, select the
OP 31, L CAL
command to force the
analog output to LOW scale output. If you are using the RS-232 serial port, press the space
bar on the computer terminal. This toggles the output between LOW, MID, and HIGH
outputs. The display on the 1250B should read “LO”. The analog output low scale may now
be adjusted by turning the “ZERO” pot, accessible through the slot in the right side of the case
(see Figure 4.1), until the output signal is reading properly on the multi-meter.
If menu commands are being used, select the
OP 32, H CAL
command to force the
analog output to HIGH scale output. If you are using the RS-232 serial port, press the space
bar on the computer terminal. The display on the 1250B should read “HI”. The analog output
high scale may now be adjusted by turning the “SPAN” pot (see Figure 4.1) until the output
signal is reading properly on the multi-meter. Repeat analog LOW and HIGH calibration
steps several times to assure proper output signal calibration of both. Some interaction may
occur between the ZERO and SPAN adjustments.
If menu commands are being used, select the
OP 33, D CAL
command to force the
analog output to MID scale output. If you are using the RS-232 serial port, press the space
bar on the computer terminal. The display on the 1250B should read “
--
”. The analog
output should read a mid-scale signal on the multi-meter. There is no adjustment for this mid-
scale output.
Figure 4.1 Analog Output Adjustment Pots