Code 320-003B: Default setting of IOC hardware is incomplete
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical Default setting of IOC hardware is incomplete 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 default setting for the use of the IOC hardware and the IOC configuration file is incomplete: (see also the machine parameter iocProject under CfgPlcPeriphery) - IOC file not found - Hardware is configured in the IOC file, but the file is not available - IOC hardware is available, but the IOC file is not configured [Error correction] - Match the configuration file and hardware. - You can find more information in the diagnostics menu
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 320-003B 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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