Code 231-A200: Brake test is not allowed %1
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical Brake test is not allowed %1 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] - Drive ready signal (RDY signal) or inverter enabling signal is missing. - Protective door(s) are not closed, although the parameter settings require it. - The brake to be tested is not assigned to this drive [Error correction] - Check the inverter enabling signals (wiring, PLC program or SPLc program) - Close the protective door(s) - Check the parameter settings, and edit them if necessary. - Inform your service agency 10/2023 [467]
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-A200 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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