Rockwell Automation 1769-IF16V Compact High Density Analog Input Modules - Manual (Page 49)

Publication 1769-UM018A-EN-P - October 2008 49
Module Diagnostics and Troubleshooting Chapter 4
Channel Diagnostics When an input channel is enabled, the modules perform a diagnostic
check to see that the channel has been properly configured. In
addition, the modules check each channel during every conversion
cycle for over-range and under-range, high and low process alarm
conditions, and open-circuit conditions.
Out-of-range Detection
Whenever data received at an input is out of the defined normal
operating range, an over-range or under-range error is indicated in the
Input Data file.
Process Alarm Detection
Whenever data received at an input meets or exceeds that channel’s
configured process alarm limits, a high alarm or low alarm error is
indicated at the Input Data file.
Open-circuit Detection
The 1769-IF16V module provides open-circuit detection on all
enabled channels. Whenever an open-circuit condition occurs, the
over-range error bit for that channel is set and the channel’s input data
reading will be at the maximum, full-range value in the Input Data
file.
The 1769-IF16C module also provides open-circuit detection on all
enabled channels. Whenever an open-circuit condition occurs, the
under-range error bit for that channel is set and the channel’s input
data reading will be at the minimum, full-range value in the Input
Data file.
Possible causes of an open circuit include:
•
the sensing device may be broken.
•
a wire may be loose or cut.
•
the sensing device may not be installed on the configured
channel.