Code 320-041D: PLC: timeout
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical PLC: timeout alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
[Cause of error] PLC runtime error: - The processing of the cyclically executed program section takes too long. Check the subprogram structure for very calculation-intensive sections that you can start as SUBMIT jobs. - The displayed processing time will be increased during data transfer and in handwheel mode. In case of doubt, select handwheel mode and simultaneously start the data transfer at max. baud rate. At the same time, check "MAXIMUM PROCESSING TIME" in the PLC programming. Values should not exceed 150% (safety reserve in the event of unfavorable operating conditions!). [Error correction] Edit the PLC program.
Source: HEIDENHAIN NC Error Messages — TNC7/640/620/320/128, CNC PILOT 640, MANUALplus 620 (10/2023)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Heidenhain TNC Series CNC Alarms
Heidenhain controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 320-041D on the TNC Series CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Heidenhain's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 4497 Heidenhain TNC Series CNC codes.
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