Encoder feedback loss

What does F00090 mean?

The drive has lost feedback from the encoder, which is critical for precise speed and position control. This can be caused by physical disconnections, a faulty encoder, incorrect parameter settings (like p0400 or p1300), or the encoder signal being outside expected limits, leading to uncontrolled motor operation or a complete shutdown.

• Encoder cable damage (e.g., broken wires, severed shield, loose connector X21) causing signal interruption or short circuits.
• Faulty encoder unit (e.g., internal sensor failure, bearing damage) not generating accurate pulses or no pulses at all.
• Incorrect encoder type selection (P0400, P0404) or number of pulses configured (P0408) in the drive parameters for the installed encoder.
• Poor signal quality due to electromagnetic interference (EMI) on the encoder cable, especially with unshielded or improperly grounded cables.
• Loose encoder mounting or excessive vibration causing physical misalignment of the encoder disk or sensor.
• Faulty drive encoder interface card or input port (e.g., X21 terminals).

Click steps to track your progress.

1. 1

   1. Power down the drive, then inspect the encoder cable for physical damage and ensure secure connections at both the encoder and drive terminals (e.g., X21).

2. 2

   2. Verify encoder parameters P0400 (Encoder type), P0404 (Encoder supply voltage), and P0408 (Pulses per revolution) match the installed encoder's specifications.

3. 3

   3. Use an oscilloscope to check the encoder A/B/Z phase signals directly at the encoder output and at the drive input terminals (e.g., X21) for pulse presence and quality.

4. 4

   4. Measure the encoder supply voltage (e.g., 5VDC or 24VDC) at the encoder connector to ensure it is within specified limits.

5. 5

   5. Ensure the encoder cable shield is properly grounded at the drive's designated grounding point (e.g., terminal 19 on X21).

6. 6

   6. If possible, test with a known good encoder or perform a basic encoder check using the drive's diagnostic functions (e.g., P0491 for encoder status).