Diagnostic WatchDogOn and ExtDiag on Profibus - AC800F
We've recently upgraded our AC800F system to have a redundancy profibus connection from controllers to CI840 clusters (using RLMs).
After the upgrade the system seems to be working fine, but we get the "diagnostic data present" (in the "standard diagnostic" tab, WatchDogOn and ExtDiag are set true).
We've tried to increase the watchdog time (TTR is set to 300000tBit and baudrate 1.5MBit/s) to 250 (*10ms) without success.
Sometimes the diagnostic data vanishes when we reset the RLM modules, but that doesn't work every time. When it works, as soon as there is a toggle from controllers, the diagnostic data returns.
How do we solve the diagnostic issue?
Did you solve the issue?
The Watchdog bit being set is perfectly normal. It just means you enabled the watchdog function for this slave, meaning after it every valid master DPv0 telegram it starts a timer. If the timer runs out before the next telegram arrives, it sets its outputs to a safe state.
As for ExtDiag, I'm not entirely sure myself (actually, this is why I found this question while looking for information). If and when ExtDiag is being set seems to depend entirely on the slave and its internal implementation (in your case, the CI840). It means that there is definitely extended diagnostic info available about this slave. The bit being cleared however *doesn't* mean there is no extended diagnostic info. Some slaves seem to use this bit to signal alarm states to the master.
Did you find out anything helpful regarding this bit?