130-0069

Access PLC program diagnostics

Press MOD key, navigate to PLC > Edit/Test, and check the cycle time display in the status bar. Cycle times consistently above 8-10ms indicate excessive load on TNC 620/640 controls.

Use the PLC Test function (MOD > PLC > Test) to monitor real-time marker states and identify loops or conditions causing high execution times.

Create minimal PLC test

Temporarily rename the current PLC program file (plc.plc or plc.src) via the file manager, create a minimal PLC with only essential I/O mapping, then restart the control to see if alarm clears.

Ensure machine safety systems are not compromised when testing with minimal PLC - maintain emergency stop and critical interlock functionality.

Review PLC error markers

Check system markers M4900-M4999 range for PLC error conditions and review any active error flags that may indicate string overflow, timer errors, or calculation faults.

Heidenhain controls log PLC runtime errors in the ErrorLog.txt file - access via FTP or MOD > System Files to see historical PLC faults.

Verify software version integrity

Press MOD key, select System Information, and record the NC Software version, PLC version, and System Software version numbers. All components should match the expected release package (e.g., all 340.49x-xx versions together).

Heidenhain controls store version information in SYS:\SYSTEM\version.txt - compare this with the physical label on the control or commissioning documentation.

Check system log files

Access TNC:\ErrorLog.txt and TNC:\System.log via FTP connection or File Manager (if accessible). Look for entries immediately before the 130-0069 alarm showing software component failures or initialization errors.

Error codes in the 0x8xxxxx range in log files typically indicate kernel-level faults requiring system software reinstallation.

Perform clean boot test

Power off the control, hold the MOD and CE keys simultaneously while powering on to access boot options. Select 'Boot with default settings' to bypass potentially corrupted configuration files.

Booting with default settings temporarily disables custom machine parameters - do not perform machining operations until parameters are restored.

Reinstall system software

If version mismatch is confirmed or logs indicate corruption, obtain the correct system software package from Heidenhain (matching your control hardware revision), backup all user data, and perform a complete system software installation via the recovery partition or USB boot media.

System software installation erases all configuration - ensure complete backup of TNC:\, machine parameters, PLC programs, and tool tables before proceeding.

Perform hardware diagnostic boot

Power off the control, then power on while holding the CE key to access the Heidenhain boot menu. Select 'Hardware Test' to run the built-in diagnostics that test RAM, CPU, and bus communication.

Hardware test results are displayed on screen but not saved - photograph any failure messages showing RAM errors, bus faults, or component test failures.

Check system temperature and fans

Access MOD > System Information > Temperature Monitoring (on controls with this feature) or physically verify all cooling fans on the main control unit are operating. Overheating can cause intermittent system errors.

Allow control to cool completely before reopening if overheating is suspected - thermal damage can worsen with continued operation.

Inspect battery voltage

Check the main CPU board battery voltage (typically 3V lithium cell) using a multimeter or view MOD > System Information > Battery Status. Low battery voltage below 2.7V can cause NVRAM and real-time clock errors triggering system faults.

Replace the CPU board battery even if voltage appears marginal - on controls over 5 years old, preventive battery replacement eliminates intermittent system errors.