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Chapter 7
Module Calibration
7-8
Calibrating Voltage Outputs (1791 N4V2 and 1791 NDV)
Use the procedure below to calibrate voltage outputs of the analog block
I/O module. The procedure can be used for either PLC or SLC systems.
The most accurate results are obtained by installing an optional load
resistor which approximates the output load for the intended application.
Important: To allow the module to stabilize, energize the module for at
least 30 minutes before calibrating.
To calibrate your module:
1.
Connect your test equipment for the output you want to calibrate.
This is shown in the figure below.
V
O
V
RET
Important: You can calibrate both outputs simultaneously.
2.
Verify normal operation.
3.
Select the calibration mode and the output and input channels you
want to calibrate.
For example, to calibrate input channel 0, set bits 15 (17), 14 (16),
and 04 of BTW word 0 (C010h).
4.
Measure the zero point with a precision meter. Enter the measured
voltage in millivolts into the BTW word (word 1 for channel 0, word
2 for channel 1).
5.
Set the EX bit (bit 07 of BTW word 0).
For PLC systems: Monitor the DN bit (BTR word 0, bit 07) until it
is set (1).
For SLC systems: Allow at least 5 seconds before continuing.
1791 N4V2 and 1791 NDV
Optional
Load
V
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