Encoder feedback loss warning

What does A00590 mean?

This warning indicates a loss of signal from the motor encoder, potentially causing the inverter to switch to sensorless vector control. Causes range from physical disconnection or faulty encoder hardware to incorrect parameterization where an encoder is expected but not configured or selected, leading to imprecise speed or position control.

• Disconnection or damage to the motor encoder cable (e.g., broken wire, loose connection at X44 terminals or motor side).
• Faulty or damaged encoder hardware (e.g., internal sensor failure, bearing issues, mechanical misalignment).
• Incorrect encoder type selected in parameters (e.g., P0400 - encoder type, P0404 - pulse count) leading to misinterpretation of signals.
• Shielding fault or inadequate grounding of the encoder cable causing excessive electrical noise interference on the signal lines (e.g., A, B, Z).
• Encoder supply voltage (e.g., 5VDC or 24VDC at X44) is out of tolerance or unstable.
• Excessive mechanical vibration or shock affecting the encoder mounting or internal components.

Click steps to track your progress.

1. 1

   1. Inspect the encoder cable for physical damage, proper routing, and secure connections at both the drive's encoder input terminals (e.g., X44) and the motor.

2. 2

   2. Measure the encoder supply voltage (e.g., Pin 1 or 2 of X44) with a multimeter to ensure it is stable and within specified limits (e.g., 5VDC or 24VDC).

3. 3

   3. Using an oscilloscope, check the encoder A, B, and Z phase signals at the drive input terminals (X44) for clean square waves and correct pulse count (e.g., P0404).

4. 4

   4. Verify the encoder parameter settings (e.g., P0400 - type, P0404 - pulse number, P0408 - direction) match the installed encoder and application.

5. 5

   5. Check the encoder cable shielding for proper termination at the drive's ground terminal and for continuity along its length.

6. 6

   6. Rotate the motor shaft by hand (if safe) while monitoring encoder signals (r0021, r0022) on the HMI to check for intermittent signal loss.