CI840A Module Faulty
I am actually installing a Freelance system comprising of AC900F and CI840A modules.
Initially all my nodes worked fine but suddenly today one node consisiting of two redundant CI840A modules, mounted on a TU847, failed.
I have already checked profibus cables , node addresses etc.
Has someone knows any way to reset the CI840A modules?
One more thing is that one of the CI840A modules has its fault LED on. Despite cycling power, the fault LED does not go off.
Wondering if it's redundant CI840A then node should work as in your case one of CI840A is giving fault the another module should keep communication healthy.
Check few things
1. Any configuration done but not downloaded and some hardware physically connected then pls download the configuration.
2. the healthy CI840A unit shows primary/secondary status ?
3. Check again cable connections/tighten them/check terminators.
4. will be good if you can share your connection diagram or picture. is there any issue on profibus master CI930F/CM772F ?
Bytheway even if TU847 is connected to power one can reset CI840/A module by unscrew xxxx it from front xxxx available on module. check image below
If you have reset the power and the fault light remains on then it sounds fairly likely that either your CI840 or TU847 base has failed. if replacing the CI840 does not resolve the problem then you may need to replace the TU847 base.
There is a known issue with some older revisions of the TU847 that can cause a "choke" capacitor to fail. The problem seems to occur more often when the air quality in your IO stations is poor.