Rockwell Automation 1746-FIO4V SLC 500 Fast Analog I/O/ User Manual - Manual (Page 61)

61 Publication 1746-UM009B-EN-P - September 2007
Chapter
6
Calibrate the Module
This chapter helps you calibrate the module’s analog input channels
to increase the expected accuracy from ± 21 LSB of error to ± 6 LSB.
The combination of calibration program and procedure is designed to
reduce offset and gain errors by:
• scaling the values read during calibration.
• applying them during runtime.
We provide example computations and ladder logic for your
reference.
Calibration Tradeoffs Operating a calibrated module requires the addition of the calibration
program for each calibrated input channel. Scanning the calibration
program increases the program scan time during runtime, slowing the
module’s response. If the overall channel error of ± 0.510% of full
scale at 25 °C (77 °F) is acceptable to your application, you need not
calibrate. If you require a calibrated input channel, consider
recalibrating every time you change the input sensor and/or the
analog module.