Code 231-9520: Erroneous input in vCtrlTimeSwitchOff %1
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical Erroneous input in vCtrlTimeSwitchOff %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] - In machine parameter vCtrlTimeSwitchOff a time of zero was configured. The time entered must permit a safe braking process. - In order to prevent an unbraked runout of axes/spindles without mechanical braking, the time in machine parameter vCtrlTimeSwitchOff must be greater than the maximum possible braking time of the axes that can occur through electrical braking. [Error correction] - Enter an appropriate value in machine parameter vCtrlTimeSwitchOff - 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 231-9520 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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