In a machine running from 2 years i'm experiencing this fault.

No hit happened. I experienced a drift: at first 1 error per day, then 2, then 10 and now i'm blocked.

What can i do? the encoder is of this series.

Of course i can change but it's a long job and i wish to have some explanation about the causes: how can the commutation angle change over the time?

Hello gtsolid 

Recently it happen with me. I don't found any reason why it's changed.

But of course we set parameter p1990 respective drive to 1.

And moves axis in possitive direction.

The parameter p1990 automatic becomes 0. 

Then save it while exiting.

You must create archive backup file before modified.

I do have the same issue (207412), but this is a new integration, these are new motors.

It really disables the axes.