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Siemens SINUMERIK Controller
System · Intermediate · 30-120 minutes
Siemens 840D 1031 - Link module generated an unspecified error NCU
Alarm 1031 indicates the NCU link module encountered an unspecified communication or interpretation error between the NCK and one or more NCU slave axes. When NCU parameter equals zero, a required non-zero parameter was not configured; otherwise, the NCK cannot decode the error response from the specified NCU, often due to version mismatch or corrupted link module communication.
1031
Siemens 840D 1031 - Link module generated an unspecified error NCU
Link module generated an unspecified error NCU
Siemens SINUMERIK alarm 1031: Link module generated an unspecified error NCU. This alarm indicates a fault or error condition on the SINUMERIK 840D control. Refer to the Siemens SINUMERIK alarm documentation for the complete description and remedy.
Root Cause Summary
Alarm 1031 indicates the NCU link module encountered an unspecified communication or interpretation error between the NCK and one or more NCU slave axes. When NCU parameter equals zero, a required non-zero parameter was not configured; otherwise, the NCK cannot decode the error response from the specified NCU, often due to version mismatch or corrupted link module communication.
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Access Diagnostics > System Information in the NCK (SINUMERIK Operate or HMI) and note the NCK firmware version and all connected NCU firmware versions.
- 2
Verify that all NCU slave axes have identical or compatible firmware revisions matching the NCK master. Check Siemens release notes for supported NCU-NCK version pairs.
Firmware mismatch will cause repeated 1031 alarms; do not operate until aligned.
- 3
If versions conflict, update the NCU firmware via the Service/Maintenance menu using the correct *.upd file from Siemens, then perform a warm restart (M0 stop, system reset).
- 4
Monitor alarm log (Diagnostics > Alarms) for secondary errors or NCU communication timeouts that confirm version incompatibility.
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