Honeywell HC900 - Page 186

Diagnostics and Troubleshooting - Scanner indicators
174 HC900 Process Controller Installation and User Guide Revision 19
06/14
Number
of
Strobes
Possible Cause Scanner Action User Action
6 The Scanner cannot communicate
to a module or the module is
experiencing a diagnostic
condition.
No action is taken. For each module with a red
blinking LED, follow the actions
described in the I/O Module
Diagnostic Indication, page 176.
6 An AI module’s CJ temperature
reading is indicating a thermal
problem. The scanner determines
this problem not the AI module;
therefore, the module’s status LED
will not indicate this diagnostic.
Possible reasons for this
diagnostic are:
1. One of the two CJs on the
module is indicating a
temperature reading greater
than 70 degrees C.
2. Both cold-junction sensors are
failing to convert.
3. The CJs are converting
properly, but their differential is
greater than 10 degrees C.
No action is taken. 1. Improve ventilation to rack
2. Replace AI module
6 The scanner determined that a
module has a bad channel. In this
condition, the module’s status LED
will not indicate the failure
because the Scanner determines
the condition, not the module itself.
No action is taken Refer to the Bad I/O Channel
Diagnostics on page 177 to
determine the nature of the
problem and possible user
actions.
7 One of the power-supplies failed. No action is taken Replace the power-supply