Ghost in the machine...
ngilbert said:
I have a micrologix 1000 that I have had to clear a fault on 3 days in a row. The error is "Unexpected Restart"...
Most likely the specific error is...
40877 - MicroLogix 1000 Major Error S:6 = 2h Unexpected reset occurred
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Linked from within that technote, you are advised to review the following technote which contains extensive information related to all the excellent advice given above, and more...
16301 - MicroLogix Controllers: Fault codes 0001H, 0002H,0004H, 0007H, 0008H, 0009H
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I would agree that swapping out the MicroLogix 1000 controller, if you can, would be the best place to start troubleshooting. This would first rule in or out any internal component failure that may be present. The fact that the controller will run for a similar period of time before each failure might suggest component breakdown due to temperature increase during normal operation.
Should swapping out the controller not resolve the issue, then the time delayed error might suggest another aspect of the machine operation that is interfering with the controller on either a cyclic basis, around the same time span as the failure occurrences, or an aspect of the machine's operation that is overheating or breaking down after continuous use up to the time of failure and then interfering with the controller.
A tricky one, but the historical evidence you've uncovered, that is the previous controller and it's intriguingly labelled "toe tag", would suggest that this issue was never truly resolved. A real
Ghost in the machine, perhaps?
Regards,
George