Cause : Serial Communication Transmission Error comes when communication has not yet been established or communications wiring is faulty, there is a short circuit, or something is not connected properly.

• Check for wiring errors.
• Correct the wiring.
• Check for disconnected cables and short circuits. Repair as needed.

1. Programming error on the master side. Check communications at start-up and correct programming errors.

2. Communications circuitry is damaged.
• Perform a self-diagnostics check.
• If the problem continues, replace either the control board or the entire drive.

3. Termination resistor setting is incorrect. Install a termination resistor at both ends of a communication line. Set the internal termination resistor switch correctly on slave drives. Place DIP switch S2 to the ON position.