Motor Stall Error

Problem

If the machine is not operating and the” information light” at the rear status panel of the machine and the firmware LED on the logic board flashes with the following eight-bit pattern as described here:

Where 0 indicates a short pulse which is 1/4 second and 1 indicates a long pulse which is 1 second long.

This will be displayed in MotorScope as a “Stall Fault”. This means that the machine doesn’t move even though the motor is powered. This error can occur on all three axes but the debugging procedure is always the same.

Solution

The following items provide step by step instructions on how to break down the cause of the issue:

1. When the machine is off, push the axis by hand. If it is very difficult to move the axis then:

   1. Check the lead screw, axis alignment, coupler, or band drive, and contact Micro-Vu support.

2. Turn the machine on and press the E-Stop. Push the affected axis by hand. Strong braking should be felt when the E-Stop is pressed. Turn the machine on and release the E-stop and place the machine on Standby. Push the affected axis by hand. Braking should be weak compared to strong braking felt when the E-stop is pressed. Compare the braking between both scenarios. If braking when the E-stop is pressed is weak (compare to the working axis), or intermittent, then one of the following has a hardware issue:

   1. Motor Cable

   2. Motor

   3. Amplifier Board

3. When the machine is running and idle, push the affected axis. It should resist motion. If the axis is very easy to push, then one of the following has a hardware issue:

   1. Motor Cable

   2. Motor

   3. Amplifier Board

   4. The cable between the Logic Board and Amplifier Board

   5. Logic Board

4. If clearing the Stall Fault causes another axis to jump (attempt to move): The motor or encoder cables are mixed up between the axis.

   1. Push the axis and watch whether the encoder values (LinPosScr) in MotorScope count in the correct axis.

5. If the axis continues to jump (attempt to move) and #4 is not occuring, then verify that the overcurrent LEDs (shown on the Image 1) on the Motor Amplifier board are not red. If any overcurrent LEDs on the Motor Amplifier board are red, then there is likely an electrical short and the following items might be defective:

   1. Cable between motor and Amplifier board

   2. Amplifier board

   3. Motor

Open

Image 1.

Open

Related articles