126-0129

Access Simulation Menu

Press MOD key on TNC keyboard, then select 'Simulation' from the menu options.

DriveSimul is distinct from 'Program Run (Full Sequence)' simulation - it simulates at the drive level, not just programmed movements.

Check DriveSimul Status

In the Simulation menu, verify if 'DriveSimul' checkbox is active (checked). If active and normal machine operation is needed, uncheck this option.

Switching out of DriveSimul mode will re-enable physical axis movement - ensure machine area is clear and axes are properly referenced.

Exit and Reference Axes

Press END key to exit MOD menu. If switching back to normal operation, perform axis reference run via 'Manual Operation' mode and reference all axes before machining.

After disabling DriveSimul, check that all axes show green 'Referenced' status in the position display before running any programs.

Verify CC Cable Connections

Power down the control properly. Check the physical connection of the CC communication cable (typically X116 on TNC side, X1 on CC side). Ensure connectors are fully seated and locking mechanisms engaged.

Always perform proper shutdown sequence before disconnecting communication cables to prevent data corruption.

Check Event Log for Communication Errors

Press MOD > System Information > Event Log. Scroll through entries looking for 'CC communication timeout', 'PLC not responding', or similar messages that occurred before alarm 126-0129.

Use the filter function in Event Log to show only 'Error' and 'Warning' priority messages for faster diagnosis.

Test CC Module Status

Press MOD > Service > Test > Hardware Information. Verify that the CC module is detected and shows 'Ready' status. Check firmware version matches TNC compatibility requirements.

CC firmware version should typically match or be compatible with TNC NC software version - check Heidenhain compatibility matrices in service documentation.

Restart with Communication Monitor

Perform controlled restart while monitoring startup sequence. If CC communication fails during boot, suspect hardware failure of CC module or communication interface on TNC mainboard.

Repeated CC communication failures may indicate CC module replacement is necessary - contact Heidenhain service for module diagnostics.

Review Hardware Configuration

Navigate to MOD > Service > Test > Hardware Information. Compare detected hardware against expected configuration documented in machine commissioning files or sysconfig.sys.

Take a screenshot or photo of the hardware information display when system is working properly for future reference during troubleshooting.

Check Inverter Module Power and Status LEDs

Open the electrical cabinet and verify all inverter modules have proper DC bus voltage (typically shown on inverter display or LEDs). Check for red error LEDs on axis modules or EnDat encoder interfaces.

High DC bus voltages present - follow proper lockout/tagout procedures and verify voltage with meter before touching any components.

Verify EnDat Encoder Connections

Check all EnDat encoder cables for proper connection at both encoder and inverter module ends. Look for bent pins, cable damage, or contamination on connectors. EnDat communication failures often cause drives to be undetected.

EnDat encoders have specific cable length limits (typically 100m for EnDat 2.2) - excessively long or damaged cables cause intermittent detection issues.

Test Individual Axis Detection

In Test mode, navigate to Axis Diagnostics and attempt to view each axis individually. Note which specific axes fail to respond or show 'Not configured' status - this isolates the failed hardware module.

If only one axis is undetected, swap its inverter module connection with a known-good axis to determine if the issue is module or wiring-related.