Rockwell Automation AADvance Controller Troubleshooting and Maintenance Manual - Manual (Page 25)

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Document: 553634
(ICSTT-RM406F_EN_P) Issue: 089:
3-3
The diagnostic systems use simple LED status indications to report a problem. The LED indications
identify the module and can also identify the channel where the fault has occurred. There is also a
summary system healthy indication for the whole controller.
The application software uses its variable structures to report a problem; these variables proved status
reports and are configured using the AADvance Workbench.
A Fault Reset button on each processor module serves to clear a fault indication. However, the
diagnostic systems will report a serious problem again so quickly there will be no visible change in the
status indications. Pressing the Fault Reset button when no fault is indicated has no effect.
Actions of the Diagnostic Systems
The diagnostic systems filter potential but non-critical fault conditions by sampling at periodic intervals
and requiring a number of matching error reports before reporting a problem. Typically the diagnostic
systems maintain a counter for a particular fault. If an error is found, the counter increments. If an
error is not found, the counter decrements, but by a smaller value. Once the counter reaches a
threshold, the diagnostic systems latch the counter and raise alarm and status indications to report the
fault.
As an example, a non-essential item might be monitored every three hours and reported after 24
hours like this.
Pressing the Fault Reset button resets every counter which has reached the fault threshold.
Latching and Non-Latching Faults
Faults occurring in the T9110 processor module are non-latching. The controller will recover
automatically, and the fault indication will clear, once the fault condition has been remedied.