231-E00A

Power cycle the control

Perform a complete power down (not just NC restart) and power up to force the control to reload all safe machine parameters from storage. Observe whether the alarm appears immediately or only under certain conditions.

Access system file directory

Press MOD key, enter password if required, navigate to the file manager, and browse to TNC:\system\ directory. Locate safemc.par file and check file size and modification date for anomalies (zero-byte file indicates corruption).

Compare file size and date with your commissioning documentation or backup files to identify unexpected changes.

Restore from backup

If you have a verified backup of the safe machine parameters (typically stored in TNC:\system\backup\ or external archive), copy the known-good safemc.par file back to TNC:\system\ directory, then perform a full power cycle.

Only restore safety parameter backups that were created for this specific machine configuration. Using parameters from different machines can create unsafe conditions.

Verify FS module communication

Navigate to MOD → System Information → CC Configuration to verify that the CC (Control Component) modules responsible for Functional Safety are communicating properly and showing correct firmware versions.

Communication errors with the FS module can also corrupt parameter loading, so verify all green status indicators for safety-related components.

Review recent parameter changes

Check the modification log in MOD → System Information → Error Log (or errorlog.txt in TNC:\system\) to identify any recent changes to machine parameters, especially those made shortly before the alarm occurred.

Look for timestamp correlation between parameter modifications and alarm occurrence—this often pinpoints the trigger event.

Access FS configuration tool

If your control has SafetyIntegrated configuration software installed, launch it through MOD function (specific path varies by TNC version) to run the built-in FS parameter validation check. The tool will identify specific parameters failing checksum validation.

Only personnel trained and authorized for Functional Safety commissioning should modify parameters through this tool.

Recompile safety parameters

Within the FS configuration tool, select the option to recompile or regenerate checksums for all safety parameters. This recalculates validation data and writes the complete parameter set with proper checksums to safemc.par.

Document the compilation process and save a timestamped backup immediately after successful recompilation.

Perform FS validation test

After recompilation, execute the mandatory Functional Safety validation test sequence as specified in your machine's safety documentation to ensure all safe functions operate correctly before returning to production.

Check software version compatibility

Navigate to MOD → System Information → Software Versions and document the NC software version, PLC firmware version, and FS module firmware version. Cross-reference these with Heidenhain's compatibility matrix documentation for your specific control model.

Heidenhain typically provides version compatibility documents with each NC software release—check the release notes in TNC:\system\doc\ directory.

Review recent software updates

If the alarm appeared after a software update, check the update log (typically in TNC:\service\) to confirm what was updated and whether the FS module firmware was included in the update package.

Never perform NC software updates without verifying the impact on Functional Safety configurations and having qualified FS personnel available.

Update FS module firmware

If version mismatch is confirmed, obtain the correct FS module firmware version from Heidenhain (matched to your NC software version) and perform the firmware update following the specific update procedure in MOD → System Update function.

Always perform FS firmware updates with the machine in a safe, non-operational state and ensure uninterruptible power supply is connected.