CPU Fault

What does CPU fault mean?

An error has occurred within the inverter's CPU or its peripheral circuits. This is a critical internal hardware fault that can lead to unpredictable operation, improper control, or complete shutdown of the inverter. Electromagnetic interference from nearby devices can sometimes trigger such faults.

• Internal CPU core failure due to manufacturing defect or aging, affecting processing integrity.
• Power supply instability on the control board leading to unreliable CPU operation (e.g., 3.3V, 5V rails).
• Watchdog timer failure, preventing the CPU from recovering from a software hang or exception.
• Corrupted CPU firmware that prevents proper initialization or execution.
• EMI (Electromagnetic Interference) causing transient errors in CPU registers or memory access.

Click steps to track your progress.

1. 1

   Record any secondary fault codes present in the fault history (Pr. 093, Pr. 094).

2. 2

   Perform a complete power cycle of the inverter, allowing full DC bus discharge before restarting.

3. 3

   Measure the control board's internal power supply voltages (e.g., 3.3V, 5V) at test points to verify stability.

4. 4

   Attempt to re-flash or update the inverter's firmware using the manufacturer's diagnostic tool (e.g., FR-Configurator2).

5. 5

   If the fault persists, the inverter control board requires replacement as the CPU is typically soldered.