PG Disconnection (Encoder Fault)

What does PGO mean?

This fault indicates a loss or disconnection of the Pulse Generator (PG) signal, which is used for speed feedback in closed-loop control modes. It signifies that the inverter is no longer receiving reliable motor speed information from the encoder. This will prevent accurate speed control and can lead to unpredictable motor behavior if not addressed.

• Loose, disconnected, or damaged encoder feedback cable between the motor and the inverter.
• Failure of the encoder unit itself (e.g., bearing failure, optical disc damage, internal electronics fault).
• Excessive electrical noise or interference on the encoder signal lines, causing corrupted pulse detection.
• Incorrect encoder wiring (e.g., swapped A/B phases, incorrect power supply polarity).
• Incorrect encoder parameter settings (e.g., pulses per revolution, output type) in the inverter.

Click steps to track your progress.

1. 1

   1. Inspect the encoder feedback cable for physical damage, proper seating in connectors, and secure terminal connections at both ends.

2. 2

   2. Measure the encoder supply voltage (e.g., 5VDC or 12VDC) directly at the encoder connector to ensure adequate power.

3. 3

   3. Use an oscilloscope to verify clean, distinct A, B, and Z channel pulse signals are present at the inverter's PG input terminals.

4. 4

   4. Check the continuity of individual encoder wires from the encoder connector back to the inverter's input terminals.

5. 5

   5. Verify encoder parameters (e.g., Parameter F3-01 for pulses per revolution, F3-02 for signal type) match the installed encoder's specifications.