PG Open Circuit

What does PGO mean?

This fault occurs when an open circuit condition is detected in the Pulse Generator (PG) feedback. This means the drive is not receiving proper speed or position feedback from the motor's encoder. This can lead to uncontrolled motor speed, position errors, or loss of precise control if left unaddressed.

• Broken or disconnected wiring between the motor's encoder (PG) and the drive's PG feedback board (e.g., terminals PG+, PG-, A, B, Z, COM).
• Damaged or faulty encoder unit itself, including internal sensor failure or mechanical damage to the encoder shaft/disc.
• Incorrect wiring connections to the PG input terminals on the drive (e.g., reversed polarity, incorrect terminal assignment).
• Missing or damaged shielding on the encoder cable, leading to excessive electrical noise that mimics an open circuit condition.
• Incorrectly configured PG feedback parameters in the drive (e.g., F1-01 Encoder Type, F1-02 Pulses per Revolution).

Click steps to track your progress.

1. 1

   Inspect the encoder cable visually for any physical damage, cuts, or crushed sections from the motor to the drive.

2. 2

   Verify all connections at the encoder end and the drive's PG feedback terminals (e.g., A+, A-, B+, B-, Z+, Z-, 5V+, 5V-, COM) are secure and correctly wired according to the manual.

3. 3

   Using a multimeter, test for continuity on each conductor of the encoder cable from end to end, confirming low resistance (<1 ohm).

4. 4

   Measure the output voltage from the encoder power supply terminals (e.g., 5VDC or 12VDC) on the drive's PG board to ensure proper encoder powering.

5. 5

   With an oscilloscope, monitor the A and B phase pulse signals from the encoder at the drive's input terminals while slowly rotating the motor shaft, verifying pulse presence and integrity.