What causes Siemens SINUMERIK alarm 101000?

Required machine data or parameter not configured for the requested function. Option bit not set in SINUMERIK to enable the required functionality. Program references a function or axis that has not been configured. Machine commissioning incomplete — required setup step was not performed. Configuration data cleared or lost due to a parameter reset or hardware change.

How do I fix Siemens SINUMERIK alarm 101000?

1. Read the full alarm message to identify what is missing (axis name, parameter number, function name). 2. Consult the SINUMERIK alarm manual for alarm 101000 for the specific configuration requirement. 3. Check the relevant machine data group and set the required parameter. 4. If a specific option is required, verify it is licensed and enabled in the SINUMERIK option settings. 5. Power cycle after making configuration changes to apply the new settings.

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Siemens SINUMERIK Controller

Program/G-code · Intermediate · 30-120 minutes

Alarm 101000

Siemens 840D 101000 - No connection to PLC !

Alarm 101000 indicates the NCK (Numerical Control Kernel) cannot establish communication with the PLC during system startup. This is typically caused by incorrect PLC basic program versions, communication hardware failures, or configuration mismatches between NCK and PLC components.

Siemens SINUMERIKProgram/G-codeIntermediate30-120 minutes

101000

Siemens 840D 101000 - No connection to PLC !

No connection to PLC !

Root Cause Summary

Alarm 101000 indicates the NCK (Numerical Control Kernel) cannot establish communication with the PLC during system startup. This is typically caused by incorrect PLC basic program versions, communication hardware failures, or configuration mismatches between NCK and PLC components.

Safety

Refer to Siemens documentation
Ensure qualified technician performs repairs

Causes and Fixes

1
Check the PLC program name and version in HMI > Commissioning > PLC. Verify it matches the NCK software version requirements (consult SINUMERIK 840D documentation for compatibility matrix).
2
Load the correct PLC basic program via SIMATIC Manager or from the Siemens commissioning package matching your NCK software version (typically found on PCU or CF card backup).
Ensure you have a backup before overwriting the existing PLC program
3
Transfer the PLC program to the PLC CPU, compile, and download. Verify no compilation errors exist in STEP 7.
4
Perform a complete power cycle (NCU and PLC) and monitor the boot sequence. Check if alarm clears and communication is established.
Wait at least 30 seconds after power-down before restarting

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