Code 320-0060: IOC configuration has invalid PLC operands
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical IOC configuration has invalid PLC operands 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 IOC configuration includes PLC operands that have already been assigned. The BUS diagnosis shows which operands are affected. Possible causes: - Use of operands that are occupied by an internal PL board. - Use of operands that are occupied by a handwheel. [Error correction] Correct the operand addresses in the IOC file: - If an internal PL board is active, then the operands I0-I32 and O0-O31 must not be used. - If the default data of a handwheel are active, then the operands I160-I175 and O96-O111 must not be used. - 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 320-0060 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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