CPU fault

What does E.6 mean?

This is a CPU fault that stops the inverter output when a communication fault occurs within the built-in CPU. Specific causes include excessive electrical noise or a short circuit between the PC and SD terminals. This critical internal error prevents safe operation.

• Excessive electrical noise or electromagnetic interference (EMI) disrupting internal CPU operations or serial communications.
• Short circuit condition between the PC connection port and the 'S' signal terminal on the control board.
• Damage to the internal serial communication interface (UART/USART) hardware on the CPU.
• Improper grounding or ground loop issues affecting serial communication lines.
• Firmware execution error leading to a CPU watchdog timeout.

Click steps to track your progress.

1. 1

   Disconnect all external devices from the inverter's communication ports (e.g., PC, PLC, HMI) including RS-485 terminals (RDA, RDB, S).

2. 2

   Power cycle the inverter completely (remove AC input power for 60 seconds) after disconnecting external communication devices.

3. 3

   Measure the resistance between the designated 'PC' signal terminal and the 'S' signal terminal to detect a short circuit.

4. 4

   Inspect the communication cable for physical damage, proper shielding, and correct termination resistors.

5. 5

   Verify that the 24VDC control power supply voltage is stable and within specified tolerance.