Mitsubishi MR-J5 AL.016 at power-up, what to check first?
I'm getting an AL.016 alarm on my Mitsubishi MR-J5 servo amplifier every time I power up the machine. This happened after I replaced the servo motor. What should I check first?
Alarm AL.016 on a Mitsubishi MR-J5 servo amplifier indicates an Encoder initial communication error 1, meaning there's a communication issue between the encoder and the servo amplifier at power-up. This can occur after replacing the motor, cable, or amplifier, or after a software reset on functional safety motors. It's crucial to address this to ensure proper servo operation.
Likely causes and checks
1Encoder cable disconnected, wired wrongly or shorted
- Points to it
- The most common cause for AL.016 at every power-up is an issue with the encoder cable, such as it being disconnected, incorrectly wired, or having a short circuit.
- Check
- Inspect the encoder cable for any disconnections, incorrect wiring, or shorts. Repair or replace the cable as needed, ensuring it is firmly connected to both the encoder and the servo drive.
2Communication method servo parameter wrong
- Points to it
- If the encoder cable communication method (two-wire or four-wire) parameter is not set correctly in the servo amplifier, it can cause this error, especially after commissioning.
- Check
- Verify that the [Pr. PC04.3] ([G] [B]) or [Pr. PC22.3] ([A]) Encoder cable communication method selection parameter is set to match the type of encoder cable being used.
3Unused axis not disabled on a multi-axis amplifier
- Points to it
- On a multi-axis amplifier, if an axis is not connected to a motor but is not disabled, it can trigger an AL.016 alarm with detail 016.3.
- Check
- If this is a multi-axis amplifier and an axis has no motor connected, disable the unused axis using the disabling control axis switches (SW3-2/SW3-3/SW3-4).
4Control circuit power supply unstable
- Points to it
- Instantaneous power failures or an unstable control circuit power supply can lead to communication errors, manifesting as AL.016 with detail 016.3.
- Check
- Check the control circuit power voltage for any signs of instantaneous power failures or instability.
Next check: After checking the encoder cable for physical issues, verify the encoder cable communication method parameter in the servo amplifier to ensure it matches your cable type.
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