The classic misjudgement with servo alarms is blaming the drive for mechanical resistance. The discriminator is the current waveform: normal at no load and rising under load points at mechanics; abnormal at no load, or spikes and oscillation, points at electrics. This page lists every servo code and how to read the waveform.
The servo closed loop: current/velocity/position loop misbehaviour, motor-drive matching and load identification target -> position loop -> velocity loop -> current loop -> power output -> motor -> feedback -> loop compare
Inspection line: look at the current waveform and read it against load ratio to separate mechanical resistance from electrical faults
Spares we carry: we bring the scope and meter; motors and drives are stocked by type, and most cases are measured before parts are ordered
FANUC 9
