Mitsubishi Electric MR-J2S-A Error AL.31: Overspeed

Servo amplifier and motor · taken from the manufacturer’s manual, pages cited

Alarm codeAL.31

Overspeed alarm indicates command pulse frequency exceeds permissible limits, acceleration/deceleration time constants are too small, or system instability causes overshoot. The manual's first action is: “Power OFF→ON”

Model
Mitsubishi Electric MR-J2S-A
Display shows
Overspeed (AL.31)
Type
Alarm code
Source
Manual p. 69

What AL.31 means

Overspeed p. 200

Common causes

  • 1. Input command pulse frequency exceeded the permissible instantaneous speed frequency. p. 200
  • 2. Small acceleration/deceleration time constant caused overshoot to be large. p. 200
  • 3. Servo system is unstable to cause overshoot. p. 200
  • 4. Electronic gear ratio is large (parameters No. 3, 4) p. 200
  • 5. Encoder faulty. p. 200

What to do

  1. Power OFF→ON p. 200
  2. Press "SET" on current alarm screen. p. 200
  3. Alarm reset (RES) p. 200
  4. Set command pulses correctly. p. 200
  5. Increase acceleration/deceleration time constant. p. 200
  6. ['1. Re-set servo gain to proper value.', '2. If servo gain cannot be set to proper value: 1) Reduce load inertia moment ratio; or 2) Reexamine acceleration/ deceleration time constant.'] p. 200
  7. Set correctly. p. 200
  8. Change the servo motor. p. 200

Before you service the product, read the safety instructions in the manual p. 3.

If AL.31 is still not resolved

  • contact service / dealer p. 3
    “Do not attempt to install, operate, maintain or inspect the servo amplifier and servo motor until you have read through this Instruction Manual, Installation guide, Servo motor Instruction Manual and appended documents carefully and can use the equipment correctly.”
  • contact service / dealer p. 4
    “Do not attempt to wire the servo amplifier and servo motor until they have been installed. Otherwise, you may get an electric shock.”
Open the manual at page 69 All MR-J2S-A error codes Manual details & download

This page summarises what the manufacturer’s manual says about AL.31; each statement links to the page it comes from, and quoted lines are copied word for word. It is not a substitute for the manual or for a qualified installer. ManualLib is not affiliated with Mitsubishi Electric. Found a mistake? Report an error.