Siemens alarm 3000: Emergency stop
SINUMERIK NCK general alarm · Siemens 840D/810D powerline
What it means
An EMERGENCY STOP request has been applied to the NCK/PLC interface (DB10 DBX56.1 on 840D/810D). All axis motions and spindle operation are cancelled, the drive enables drop, and the channel goes to 'not ready'. The alarm remains until the e-stop chain is healthy again and the PLC acknowledges removal of the request.
Likely causes
- E-stop pushbutton pressed, wired loose or defective
- Safety guard/door interlock open or faulty switch
- Broken conductor or missing 24 V anywhere in the hardwired safety chain
- Safety relay/contactor failure, or PLC user program issuing e-stop
Triage note: Trace the open contact in the safety chain (door switches, e-stop buttons, relays); never bridge safety circuits.
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