Rockwell Automation 1746-FIO4V SLC 500 Fast Analog I/O/ User Manual - Manual (Page 66)

Publication 1746-UM009B-EN-P - September 2007
66 Calibrate the Module
Calibration Procedure
Recalibrate every six months, or as necessary.
1. Let the module warm up under power for at least 20 minutes at
ambient operating temperature.
2. Determine the scaled high and low values you wish to use in
your application.
In this example, scaled high is 2047 (20 mA) and scaled low is
409 (4 mA).
3. Capture the Lo calibration value.
a. Place the input sensor (or input source) at the low (4 mA)
position.
b. Set the Cal Lo bit (I:1.0/0) and OSR bit (N10:0/0).
Your low value must be within the analog input’s conversion
range. For this example, it is 400.
4. Capture the Hi calibration value.
a. Place the input sensor (or input source) at the high (20 mA)
position.
b. Set the Cal Hi bit (I:1.0/1) and OSR bit (N10:0/1).
Your high value must be within the analog input’s conversion
range. For this example, it is 2055.
5. Set the Calibrate bit (I:1.0/2) and OSR bit (N10:0/2) to energize
the calibration input.
This causes the SCL instruction to compute and store the slope
and offset values used to perform the error correction to the
analog input.
IMPORTANT
To apply calibration values to the input channel during normal
operation, enable rung 2.4 during runtime.