CPU 1512F, TIA Portal V19 (latest update).
Three Motion Control technology objects with Sinamics V90 drives, Telegram 105, speed control mode, used as simple independent positioning axes.

The CPU is always active and backed up by UPS. Every time I switch off the power supply to the servo motors, after powering them back on it becomes impossible to re-enable the axis with the MC_Power block. Some errors are reported on the encoder (absolute) and also on the adaptation (specific error). Resetting the faults with MC_Reset has no effect.
The only way to recover is to pretend to make a modification in the technology object and then re-download everything to the CPU, even though in fact no changes were made.

The only thing that comes to my mind (and maybe I did it) is that at some point I created an image of all DBs,all of them, and saved the actual values as initialization values. Could this have an impact on the initialization of the axes? It seems unlikely to me. 

Have you tried to restart TOs? MC_Reset.Restart := TRUE

jacek d

Have you tried to restart TOs? MC_Reset.Restart := TRUE

This is in fact the only solution I managed to get working today, but: it’s the first time I’ve needed it; it never happened before, neither on previous machines nor with earlier TIA versions. What’s even more curious is that this error only appears in a second stage, after the drive becomes available again. For this reason, I assume it might be caused by some corrupted DB. If instead this is normal behavior, I can’t understand why I never came across this issue in previous configurations.