Code 231-9500: DQ: Inverter not found %1
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical DQ: Inverter not found %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] - Not able to establish communication with the inverter of the displayed axis. - The DRIVE-CLiQ line is not connected, or incorrectly connected. - The supply voltage of the inverter has been interrupted. - The inverter is defective. - Machine parameter pwmSignalOutput is incorrect. [Error correction] - Check the cabling. - Check the supply voltage of the inverter. - Check the entry in machine parameter pwmSignalOutput. - Inform your service agency 10/2023 [449]
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 231-9500 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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