Siemens alarm 2130: 5V/24V encoder or 15V D/A converter undervoltage
SINUMERIK NCK general alarm · Siemens 840D/810D powerline
What it means
A failure occurred in the power supply feeding the encoders (5 V/24 V rails) or the +/-15 V D/A converter supply generated on the NC module. Encoder feedback integrity is compromised, so position control can no longer be guaranteed and axes are typically taken to a stop. Isolating whether an external consumer drags the rail down or the NCU supply stage itself is faulty is the key diagnostic step.
Likely causes
- Short circuit or excessive load on an encoder cable (damaged insulation, crushed cable)
- Coolant/water ingress in an encoder connector
- Defective measuring system drawing overcurrent
- Ageing voltage regulator / DC-DC converter stage on the NCU
Triage note: Disconnect encoder cables one axis at a time to find a shorted branch; persistent alarm with all cables disconnected indicates NCU hardware.
Need the part urgently?
Send us alarm 2130 with your machine details — typical RFQ turnaround is 24–48h.