Siemens alarm 168*: Servo enable, trav. axis
SINUMERIK 810/820 legacy alarm · Siemens 810/820
What it means
The axis-specific servo-enable signal from the PLC user program was removed while the axis was traversing. The NCK brakes the axis in a controlled way and enters follow-up mode - a signature of safety circuits, guard interlocks or worn enable relays opening mid-motion.
Likely causes
- Intermittent safety/guard door circuit
- Worn enable relay contacts in the cabinet
- PLC logic error withdrawing enable under motion
Triage note: * suffix = axis index
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