Troubleshooting Motors

NI Motion Measurement & Automation Explorer

Troubleshooting Motors

Complete the steps in the following sections if your motors do not move as expected when you test them:

Check the Motion Controller

  • Ensure that the cable is not loose on either end.
  • Check the polarities of the inhibits to make sure they match the hardware settings on the UMI or drive.
  • Before turning on the drive, check that the encoders work correctly. When the encoders are working correctly, the encoder counts increment and decrement on the 1-D Interactive tab in Measurement & Automation Explorer (MAX) when you move the motor manually.
    • Turn the motor clockwise, or in the forward direction, to increment counts.
    • Turn the motor counterclockwise, or in the reverse direction, to decrement counts.
      Tip  Moving the motor in a forward direction typically increments the count, and moving the motor in a reverse direction typically decrements the counter, but not always. Refer to the motor documentation for information about incrementing and decrementing the count.
  • Turn on the drive.
  • For servo motors, check the following error status to ensure the motor is not tripping out on following error immediately after the start of a move. This situation may occur if the encoders or motors are wired incorrectly.

Check the Drive

  • Ensure that the drive is enabled. Most drives have a reset or enable switch.
  • If you are using a UMI, ensure that 5 V is being supplied for encoder power.
  • If you are using brushless servo motors and the drive is handling the commutation, ensure that the Hall effect sensors and encoders are connected to the drive correctly. Refer to the drive documentation for information about connecting the drive to motion controllers.
  • Most servo drives must be configured. If the servo drive comes with tuning or configuration software, ensure you have installed it and configured the drive for torque/current, velocity, or p-command mode.
    In most cases, the NI motion controller closes the position loop, so the position loop typically should not be closed by the drive. The following table includes considerations to make in other circumstances:

    Using the drive in p-command mode for 73xx controllers.Use the drive configuration software to tune the position loop.
    Using the NI SoftMotion Controller for CANopen.Use the drive configuration software to tune the position loop.

    The velocity loop can be optionally closed on the drive. Make sure that the gains for the drive are properly adjusted for the motor you are using.
  • If you are using stepper motors, ensure that the step and direction lines are connected according to the requirements of the drive. In some cases, a pull-up resistor may be required.