Code 330-0008: Inverter not ready
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical Inverter not ready 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] - Power-on of the drive not possible, because an inverter is not ready (RDY signal). - On interface PCBs for Siemens inverters, the second axis is not enabled - No switch signals to the inverter contacts or relays - Compact inverter, inverter supply unit or power module is defective - Interruption at inverter bus cable (supply bus, unit bus, PWM bus) - Defective PWM interface on the control [Error correction] - Remove interruption in the electrical cabinet - Replace the defective compact inverter, supply unit or power module - Replace the defective cable - 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 330-0008 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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