Rockwell Automation 1746-NT8 SLC 500 Thermocouple/mV Analog Input Module User Manual - Manual (Page 73)

1 Publication 1746-UM022B-EN-P - January 2005
Chapter
6
Troubleshooting Your Module
This chapter describes troubleshooting with channel-status and
module-status LEDs. It explains the types of conditions that might
cause the module to flag an error and suggests what corrective action
you could take. Topics include:
•
module and channel diagnostics
•
LED indicators
•
interpreting I/O error codes
•
troubleshooting flowchart
Module and Channel
Diagnostics The module operates at two levels:
•
module level
•
channel level
Module-level operation includes functions such as powerup,
configuration, and communication with the SLC processor. Channel
level operation includes functions such as data conversion and open
circuit detection. The module performs internal diagnostics at both
levels and immediately indicates detected error conditions with either
of its status LEDs. See the LED troubleshooting tables on page 6-3 for
LED operation.
Module Diagnostics at Powerup
At module powerup, the module performs a series of internal
diagnostic tests. If the module detects a failure, the module status LED
remains off.
Channel Diagnostics
When a channel is enabled, the module checks for a valid
configuration. Then on each scan of its inputs, the module checks for
out-of-range and open-circuit fault conditions of its inputs including
the CJC input.
When the module detects a failure of any channel diagnostic test, it
causes the channel status LED to blink and sets the corresponding