AC900F Redundancy problem
I have a problem with 900F controller ; As the primary and secondary controllers are running with Sync condition but once I toggle the primary controller to test the redundancy , all variables become initial values immediately which affect DO and AO values also.HINT: The controllers don’t have internal batteries till now , does it affect the redundancy ??
How did you toggle the controllers? Can you provide information about how you did the cabling and termination of the PROFIBUS with respect to the redundancy?
If you created a fail-over by removing power from the primary and had the PROFIBUS terminated at the plug in the primary (instead of terminating it seperately with its own power supply), then the power of the termination (which needs to be active all the time) was also gone, leaving the PROFIBUS without an active termination on one end. That can lead to disturbances of the PROFIBUS communication which in turn can prevent the secondary from taking over the PROFIBUS in time. This can lead to the observed behaviour.
Otherwise your description could indicate the secondary did a cold-start instead of taking over bumpless.
Also see here: https://forum-controlsystems.abb.com/20215864/Freelance-900F-controllers-redund
Can you provide the diagnostics data from primary and secondary for your toggle event?