Code 231-D400: Data transm. SPL to CC, watchdog error at HSCI addr.:
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical Data transm. SPL to CC, watchdog error at HSCI addr.: 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
%1 [Cause of error] - Data transmission error in the HSCI system - A safe PL 6xxx FS is transmitting erroneous data - The HSCI transmission is disturbed [Error correction] - Software update - Exchange the PL 6xxx FS - 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-D400 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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