We use compact field point controller for one of our hydraulic test stands.
And cFP-DO-401 is configured for sequence of boolean operations for all the 16 channels.
The problem is during testing, status indicators are turned off but internally the relay still on , so operation gets failed.
When i checked for cause, some of transistors in the cFP-DO-401 got short circuited.
I want to know what might be the root cause of the failure or problem.
The cFP-DO-401 module may have been damaged by high voltage transients. When a channel of the [c]FP-DO-400/401 is damaged, the channel will remain in the ON position. Though the LEDs will turn on and off correctly, the module will always output a HIGH voltage. To prevent against this type of failure in the future, you need to place a properly selected transient voltage surge suppressor (TVSS) between V and C of the module. Refer to page 11 of the manual for this caution.
See this KB for more information.
Meanwhile the cFP-DO 401 module had a redesign in June 2008 to include the voltage suppressor.
I would just like to add that the correct URL to the KnowledgeBase link that Dirk posted is here: