Rockwell Automation 1794-IF4I, -OF4I, IF2XOF2I, -IF4IXT, -IF4ICFXT, -OF4IXT, IF2XOF2IXT FLEX I/O Isolated Analog Modules - Manual (Page 129)

Publication 1794-6.5.8 - January 2010
Calibrating Your Module 127
4. Send a block transfer write with the output values for offset
voltage to the module (–31208 for –10V mode 2). Measure the
output.
Calculate the offset correction for each channel:
offset_corr = (–10V – measured_value) X 3120.7619
5. Enter these offset corrections in the output word for each
channel being calibrated.
6. Send a block transfer write with the IC bit and the CK bit set to
1. With GO low (0), the module copies the “offset_corr”
coefficients (signed 2’s complement format) from the data words
into offset storage for the selected channels. If you set RV high
(1), default values will be copied to all channels.
7. With a BTW, reset the CK bit (0). With the GO bit low (0), the
previously determined offset coefficients are stored in EEPROM
for the selected channel.
8. Monitor the block transfer read. Clear the IC bit to 0. Offset
calibration is completed.
Gain Calibration for Outputs
1. Send a block transfer write to the module to set the output
values for gain voltage; +31208 for +10V mode 2. Measure the
output. Calculate the gain correction for each channel as
follows:
gain_corr = (+10V – measured_value) X 3276.76
2. Enter these gain corrections in the output word for each channel
being calibrated.
3. Send a block transfer write with the CK bit set to 1. With GO
high, the module will copy “gain_corr” coefficients (signed 2’s
complement format) from the data words into gain storage for
the selected channels. If RV is high, default values will be copied
to all channels.
4. Send a block transfer write with CK set to 0. With GO high, the
previously determined gain coefficients are stored into EEPROM
as directed by the channel selection.
5. Clear the IC bit to 0. Gain calibration is terminated.