PLC HALTED

[Guardiano]

Hi,

A strange phenomenon happened in my plant yesterday night.The PLC stopped and the supervisory computer had the computer date changed to 2016.Both PLC and computer are powered through a fully online UPS which is itself powered through an isolating transformer.The UPS did not record any anomality and nothing anormal on the voltage side was noticed in the plant.The plant is powered by its own generator set.
Could forum members shed some light on the cause of this stoppage.

Guardiano

 

[Skogsgurra]

Make and type of PLC? Power supply? Longest cable? Newly installed? First time it happens? Ever considered an April 1st thing?

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[EmergencyPowered]

Almost all major PLC brands have a fault table. Is there anything there?

 

[Guardiano]

I am rather looking for a power quality problem.The PLC halted on CPU fault and the supervisory computer's date changed to 2016.I presume the cause could be a earthing problem.

Guardiano

 

[PHovnanian]

Is there any protocol between the supervisory computer and PLC that sets a time register in the PLC? Its possible that your computer suffered a hiccup in its clock and the PLC subsequently shut down when some time dependant function didn't like the big jump.