Simultaneous Forward/Reverse Rotation Command

What does ef mean?

This warning occurs when both forward and reverse rotation commands are simultaneously detected for 0.5 seconds or more. The inverter will decelerate and stop the motor to prevent conflicting commands and potential damage. It indicates an issue in the control sequence logic.

• Incorrect wiring of the forward (SF) and reverse (SR) run command terminals, leading to simultaneous activation.
• Faulty control relay or PLC output module providing simultaneous run commands to inverter input terminals.
• Programming error in the PLC or control system allowing both forward and reverse commands to be active concurrently.
• Incorrect parameter configuration (e.g., P04, P05) where input logic is misinterpreted, leading to conflicting commands.
• Internal inverter control board fault (less common, but possible).

Click steps to track your progress.

1. 1

   De-energize the inverter and control circuit. Verify control wiring from the PLC/controller to inverter terminals (e.g., SF, SR) for shorts or misconnections.

2. 2

   With the control circuit energized (but inverter in STOP mode), measure voltage at inverter control terminals (e.g., SF, SR) to confirm only one command is active at a time (e.g., 24VDC for forward, 0VDC for reverse, or vice-versa).

3. 3

   Review PLC/controller output logic and program to ensure interlocking prevents simultaneous forward/reverse commands.

4. 4

   Check inverter parameter settings for input terminal assignments (e.g., P04 for SF, P05 for SR) and logic (e.g., P0-01 for input terminal selection) to ensure correct configuration.

5. 5

   If external control is via a network protocol (e.g., Modbus), check the network communication for conflicting command messages.