Encoder Cable Fault

What does 7310 mean?

A pulse encoder phase signal is missing, indicating a problem with the encoder connection or the encoder itself. This will result in a loss of accurate motor speed and position feedback, causing erratic motor control or complete shutdown of the motor.

• Broken wire or loose connection in one or more encoder signal lines (e.g., A, B, Z, or their complements) at the encoder or drive terminal.
• Shielding fault or improper grounding of the encoder cable, leading to significant electromagnetic interference (EMI) on signal lines.
• Failure of the encoder unit itself, preventing it from generating accurate pulse signals.
• Incorrect wiring of the encoder power supply (e.g., 5VDC or 24VDC) causing the encoder to not power up.
• Incorrect pulse count setting (e.g., P3-01) for the encoder, leading to misinterpretation of signals by the drive.

Click steps to track your progress.

1. 1

   1. Measure the voltage on the encoder power supply pins (e.g., 5VDC or 24VDC) at the encoder connector and verify against the encoder's specification.

2. 2

   2. Using an oscilloscope, monitor the encoder A and B phase signals at the drive's encoder input terminals while rotating the motor shaft slowly, checking for clean square waves.

3. 3

   3. De-energize and lock out power, then perform a continuity check on each individual wire within the encoder cable from encoder to drive terminals.

4. 4

   4. Verify the encoder cable shield is properly connected to ground (PE) at the drive end, and isolated (or properly terminated) at the encoder end.

5. 5

   5. Check parameter P3-01 (Encoder pulse count) and ensure it matches the actual resolution of the connected encoder.