I have this problem on my machine.
It is Fanuc OM and machine DAH-LIH.
Everything is fine, machine is working and sudenly at one moment, z axis goes down and tool hits into table.
And display "434 servo alarm: Z axis detect error"
And after that i restart machine and everything is ok, and from time to time, it happens again.
What could that be?
Sorry if this is wrong forum