Code 231-C031: Alarm with supply voltages
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical Alarm with supply voltages 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] The supply voltages on a device in the HSCI line are outside of the specified range. The HSCI bus diagnosis indicates which HSCI component triggered the error. Possible devices: - MC main computer - PL inputs/outputs - MB machine operating panel - Other CC in the HSCI line Possible causes: - Insufficient power supply to the devices - Short circuit in the power supply - Short circuit in PL inputs and outputs [Error correction] - Check the voltage supply to the devices - Note further information in the control's diagnostic functions (bus diagnostics or TNCdiag) - Check the wiring for possible short circuits (e.g., PLC inputs or outputs) - Exchange the hardware - Inform your service agency
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 231-C031 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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