Code 320-0028: Invalid configuation for PLC arithmetic error
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical Invalid configuation for PLC arithmetic error 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
operand %1 [Cause of error] The configuration for treatment of PLC arithmetic errors is illegal. [Error correction] Correct the configuration under consideration of the following constraints: - Examine the MULERROR, DIVERROR, and MODERROR entries in the configuration file for the PLC compiler (see entry under CfgPlcPath) - PLC programs that use the TNC marker interface can use only the markers M4200 to M4202 - Symbolic operands must be defined in the PLC program
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 320-0028 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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