Module Calibration
Chapter 7
7-10
Calibrating Current Outputs (1791N4C2 and 1791NDC)
Use the procedure below to calibrate current outputs of the analog block
I/O module. The procedure can be used for either PLC or SLC systems.
You can calibrate any single input or output individually or, you can
calibrate them simultaneously.
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 input you want to calibrate. This
is shown in the figure below.
I
O
I
RET
Optional
Load
A
1791N4C2 and 1791NDC
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
current in milliamps 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.
