MASSO Closed Loop stepper Troubleshooting



Permanent Alarm indication


  • The Red LED lights permanently when it looses steps and ca no longer recover.
  • If an error occurs because of insufficient power available to drive the motor
  • If the pulse rate exceeds the maximum that the motor can process.

In these cases repowering the motor will clear the alarm


  • Check the motor enable is receiving the enable signal from MASSO.
  • With a meter check the voltage between the -ve of the motor and the EN input of the motor. You should see a voltage of 5 to 24 volts and if you do not see this voltage you may have a broken wire.

The only thing needed to clear the Alarm LED on power up is the enable signal.




If you get a motor alarm but the motor does not show an alarm indication

  • Check the motor alarm input on the MASSO F1 settings screen.
  • The Motor alarm input should show Low when there is no alarm indication on the motor.
  • The motor alarm input must not be inverted.
  • If there is no alarm LED on the motor but the Alarm input is showing High, check the AL wire between the motor a the MASSO input as it is fail safe and it there is a break in the wire the alarm input ill go high.
  • If this is a new installation ensure that the 10K resistor is installed and the motor power supply negative rail ic connected to the negative of the MASSO Power supply.




Flashing LED Indications


Closed-loop stepper motor, position out of tolerance fault analysis and treatment

Phenomenon: The red light flashes five times at 08 second intervals and then repeats after 2 seconds


Reason 1: Check the wiring, whether there is a wrong connection or poor contact.

Solution: Make sure that the wiring is making good contact and connected correctly.


Reason 2: Check the speed and acceleration time, if the speed is too fast and the acceleration time is too short, it may cause an alarm.

Solution: Appropriately reduce the speed and reduce the acceleration speed.


Reason 3: Check the structure and load, whether the structure is stuck, whether the load is too heavy, which may cause an alarm.

Solution: Adjust the structure to ensure smooth travel, and reduce the drive load test. Check the machine for binding on the faulty axis.


Reason 4: The above is no problem, replace the motor or driver.

Solution: Replace the motor with the same model and do the exclusion test. This is best done by swapping the motor with another of the same type on the machine and see if the fault moves axis or stays on the same axis. If the fault stays on the same axis there is a mechanical problem and if the fault moves to the new axis then the motor is at fault.