Calibrating voltage outputs, Offset calibration for voltage outputs 126 – Rockwell Automation 1794-IF4I, -OF4I, IF2XOF2I, -IF4IXT, -IF4ICFXT, -OF4IXT, IF2XOF2IXT FLEX I/O Isolated Analog Modules User Manual

Page 128

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Publication 1794-6.5.8 - January 2010

126 Calibrating Your Module

Calibrating Voltage Outputs

Voltage calibration requires offset calibration followed by gain
calibration.

Offset Calibration for Voltage Outputs

Refer to the output timing diagram when calibrating the module.
Normally all outputs are calibrated together. To calibrate the offset of
an output, proceed as follows:

1. If you are not calibrating all channels with the same

configuration, select the channel to be calibrated by setting the
bit for that channel.

2. Send a block transfer write (BTW) to the module with individual

channel bits set for the configuration desired for each output.
This effectively terminates any previous configuration of the
module/channel.

Figure 7.3

Output Calibration Timing Diagram

3. Clear all offset and gain coefficients by :

a. Set output data to 0 and the IC bit to 1

b. With GO = 0, toggle the CK bit

c. With GO = 1, toggle the CK bit

d. Clear the IC bit

Bit 15

Bit 14

Bit 07

Bit 06

Bit 05

Bit 04

Bit 01 ± 03

Configuration

Gain

Offset

1

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