Omron · MX2 Series Type V2 Compact Inverter
This fault is detected if the motor's actual rotation speed (feedback from the encoder) remains below the 'Starting Frequency' (b082) for a duration longer than the 'Encoder Disconnection Detection Time' (P077), while the output frequency is at or above 'Creep Speed Setting' (P015). This suggests a disconnection or malfunction of the encoder, or incorrect detection settings.
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1. Power off the inverter, disconnect the encoder cable at both ends, and perform a continuity test on all wires (e.g., A+, A-, B+, B-, Z+, Z-, 5V+, GND).
2. Measure the encoder supply voltage (e.g., +5VDC or +12VDC) at the inverter's encoder terminal block (e.g., X2 pins 1 and 2).
3. Verify parameter b082 (Starting Frequency) and P2-06 (Encoder Disconnection Detection Time) are set appropriately for the application.
4. With the motor rotating slowly (if safe), use an oscilloscope to check for pulse signals (A/B phases) at the encoder output terminals.
5. Inspect the encoder mounting for looseness or damage, ensuring the encoder shaft coupling is intact and rotating with the motor shaft.
6. If all checks pass, replace the encoder unit on the motor as it may have failed internally.