Code 235-00AC: Module missing in HSCI device
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical Module missing in HSCI device 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] On device %4 with the serial number %5 at HSCI address %3, at least one configured module is missing. Due to ambiguities, the missing modules cannot be identified precisely. The possible devices are listed below: Info: Type (slot) Configuration: %1 Hardware: %2 Possible causes: - Option for configuring the hardware expansion was set incorrectly - Module not connected - Module in wrong slot [Error correction] - Check configuration and the options in effect - Check the module structure of the device You can use the diagnostics functions of the control for this.
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 235-00AC 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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