Siemens Sinumerik 808D and 828D systems report faults from three areas: the NC (CNC core), the PLC (machine logic), and the SINAMICS drive (servo/spindle power). The alarm number tells you which area. Below are the codes seen most often, with causes and fixes.
How Siemens Alarm Numbers Are Grouped
- 0xx – 9xxx — NC / general alarms
- 2xxxx (e.g. 25000, 25201) — Axis / channel alarms
- 4xxx (e.g. 4060, 4065) — Machine-data / system messages
- 700xxx — PLC / user (machine builder) alarms
- F30xxx / F31xxx / F7xxx — SINAMICS drive Faults (Axxxxx = warnings)
Common NC & System Alarms
| Alarm | Meaning | Common Cause & Fix |
|---|---|---|
| 4060 | Standard machine data loaded | Information message after a data reset / first power-up. Load the correct machine archive (commissioning data). |
| 4065 | Buffered memory restored from backup | Battery-backed data was lost and restored. Check the NC backup battery; reload data if needed. |
| 3000 | Emergency stop | E-stop active. Release the button, check the safety chain and PLC interlocks, then reset. |
| 25000 | Axis hardware encoder fault | Encoder/measuring system fault on the axis. Check the encoder cable, connector and feedback. |
| 25201 | Axis drive fault | A SINAMICS drive fault is active for this axis — read the F-code on the drive (see below). |
| 700xxx | PLC / machine-builder alarm | Custom message defined by the machine builder (lube, air, hydraulics, doors). Read the alarm text and clear the named condition. |
Common SINAMICS Drive Faults (F-Codes)
These show on the 828D drive/diagnosis screen (and on the SINAMICS module) and usually trigger a 25201 on the channel.
| Code | Meaning | Common Cause & Fix |
|---|---|---|
| F30001 | Overcurrent | Motor short, ground fault, or wrong drive/motor data. Megger the motor and cables; check drive parameters. |
| F30002 | Overvoltage (DC link) | Regenerative / rapid-decel over-voltage, or high line voltage. Check braking resistor and supply. |
| F30003 | Undervoltage (DC link) | Input supply loss, blown fuse, or infeed/contactor fault. Check the line supply and infeed module. |
| F30004 | Inverter overtemperature | Cooling fan failure or blocked heatsink. Clean and replace the drive fan; check ambient temperature. |
| F30005 | Inverter I²t overload | Continuous overload. Reduce cutting load; check for mechanical friction/bind. |
| F30011 | Line phase failure (main circuit) | Missing input phase. Check the 3-phase supply, fuses and contactor. |
| F30015 | Motor cable phase failure | Open/loose motor power lead. Check the motor cable and terminals. |
| F30021 | Ground fault | Insulation breakdown in motor or cable. Megger-test and repair/replace. |
| F31xxx | Encoder fault (e.g. F31100/F31110) | Measuring-system fault. Check the encoder, its cable and the DRIVE-CLiQ/feedback connection. |
| F7011 | Motor overtemperature | Overload, blocked motor cooling, or faulty motor temperature sensor. |
First Steps When a 808D / 828D Alarms
- Note the alarm number and full text — it states the area (NC / PLC / drive).
- For 25201 / F-codes, open the drive diagnosis to read the exact SINAMICS fault.
- Check the infeed/line supply, DC link voltage, cooling fans and the encoder/DRIVE-CLiQ wiring.
- For overcurrent/ground-fault codes, megger the motor and cables before refitting a drive.
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This is a quick-reference of commonly encountered alarms. For the complete official code list, always refer to the Siemens Sinumerik 808D / 828D Diagnostics Manual.