Code 235-0062: Unknown device on HSCI bus (%1)
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical Unknown device on HSCI bus (%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] The NC software identifies every connected device by means of a device table. The table indicates whether the device is supported by the software version installed on the control. A device that the software does not support or that is not yet entered in the device table is connected to the HSCI bus. The device concerned is indicated in the additional information. The device table might have been overwritten by installing an update that was generated by an older software version. [Error correction] - Inform your service agency. - Update the NC software if the device is not supported by the currently installed version of the NC software. - Update the device table. The installed software might be able to control a new device that is not yet listed in the device table. In this case the device table must be updated.
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 235-0062 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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