Rockwell Automation 1715-OF8I Redundant I/O System User Manual - Manual (Page 271)

Rockwell Automation Publication 1715-UM001C-EN-P - March 2014 271
Appendix
C
1715-IB16D Digital Input Module Diagnostics
Threshold Values for Digital
Inputs
This section describes how to calculate and set threshold values for digital inputs.
The module determines the channel state and the line fault status by comparing
the channel input voltage with defined threshold values. Line faults, such as short
circuit and wire off, can be determined by using different input voltage values.
With this module, the user can define custom threshold values or use a set of
preset default values. The types of threshold values you choose initially for the
module become inherent in each channel; you can define different thresholds for
individual channels later.
The threshold values determine which end-of-line (EOL) resistor value you
choose, and vice versa, depending on whether you choose the threshold values
first, or the EOL resistor values first.