What causes Siemens SINUMERIK alarm 20106?

Digitizing probe collision or overtravel triggered the probe E-stop output. Digitizing system cable fault generating a false E-stop signal. Digitizer interface module fault or power supply issue. Probe signal conditioning unit reporting an error state that activates E-stop. Digitizer software on the external computer triggered an emergency stop command.

How do I fix Siemens SINUMERIK alarm 20106?

1. Check the digitizing probe for physical collision damage or probe stylus deflection. 2. Reset the digitizing probe system and verify the probe stylus is undamaged and centered. 3. Check the digitizer interface cable for damage or loose connections. 4. Verify the digitizing system power supply and interface module status. 5. If the probe appears undamaged, check the digitizing software for error messages on the external computer.

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Siemens SINUMERIK Controller

Safety · Intermediate · 30-120 minutes

Alarm 20106

Siemens 840D 20106 - Emergency stop set by the digitizer

Alarm 20106 indicates the digitizing unit (probe/touch trigger sensor) has detected a critical fault condition and autonomously triggered an emergency stop via the NCK safety circuit. This typically involves hardware malfunction, signal integrity loss, or unsafe probe state detection that prevents continued axis motion.

Siemens SINUMERIKSafetyIntermediate30-120 minutes

20106

Siemens 840D 20106 - Emergency stop set by the digitizer

Emergency stop set by the digitizer

Root Cause Summary

Alarm 20106 indicates the digitizing unit (probe/touch trigger sensor) has detected a critical fault condition and autonomously triggered an emergency stop via the NCK safety circuit. This typically involves hardware malfunction, signal integrity loss, or unsafe probe state detection that prevents continued axis motion.

Safety

Refer to Siemens documentation
Ensure qualified technician performs repairs

Causes and Fixes

1
Verify physical probe connection at the probe head and control cabinet terminal block. Check MD 37000 (ProbeType) and MD 37010 (ProbeTouchSignalType) match the installed probe model in Diagnostics > Measuring Probe menu.
Do NOT bypass safety interlocks. Confirm E-stop is active before servicing probe hardware.
2
Test probe signal in NCK diagnostics: Navigate to Diagnostics > Inputs/Outputs > Probe Input (typically DI port assigned in MD 37100). Trigger probe mechanically and verify signal state change from 0 to 1 (or inverted logic per MD 37020).
3
If signal does not respond, measure continuity and voltage at probe connector using multimeter. Expected: 24V logic signal with <100ms response time. Check harness for pinch damage or moisture ingress.
4
Replace probe or harness assembly and re-initialize probe calibration via Diagnostics > Measuring Probe > Calibration. Clear alarm with soft reset (MDI: RESET) or hard reset if required.

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