Timer changed by itself

[jvalstar]

Today I had a problem with a timer from a big program made in Visilogic. 

2 months after downloading a new program into the V130, a timer changed itself from 00.00.00.09 to 99.59.59.99. The timer is only used by one contact and one coil.

Did anyone ever experienced this too? And how can I prevent it from happening again?

Thank you!

[Flex727]

I've seen a power glitch (or surge) change timers before. Not sure how to prevent it other than make sure the power source is as clean as possible.

[jvalstar]

Thank you for your answer. It is kind of weird only one timer had changed its value. The other +- 50 timers aren't changed. 

[Flex727]

All electronic equipment is subject to the vagaries of power supply and ambient electrical noise - sad fact of our lives. Still better than working in retail.

[Ausman]

Agree.  I have had other plc brands get their EEPROMs completely changed, even though they are on very good filtered supplies and well enclosed.  How?  "Well....we did have a funny power thingy happen......"

And.....wait until a lightning bolt happens nearby.  I had one go metres above, but right over a roof loaded with HVAC equipment.  Scared the poo out of everyone in the building.  Nothing happened to the well located plc gear which runs it all directly from an internal spot, but a host of pressure sensors inside the metal enclosed mechanicals on the roof all got fried.  We also get hits near our house, and this can play havoc with various electronics supposedly built to tolerate such things, particularly alarms with their simple unshielded cabling.  Even the best attempts at suppression/protection measures can't compete with Mother Nature if she decides she's going to win!

cheers, Aus