Code 238-101D: UVR%2 configured DC-link voltage too low
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical UVR%2 configured DC-link voltage too low 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 DC-link voltage configured in MP_dcLinkVoltage is too small. The configured DC-link voltage must be greater than the rectifier value of the live line voltage. If a power supply unit is operated, for example, with a line voltage of 3AC 480 V, the machine manufacturer must increase the DC-link voltage to be generated to DC 720 V by means of MP_dcLinkVoltage. [Error correction] - Check the entry in the parameter CfgSupplyModule3xx/MP_dcLinkVoltage and adjust it if necessary. - 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 238-101D 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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