Automatic Motor Set (Auto-MSET)

You can use the Auto-MSET method or the Commutation Search method to initialize the motor commutation for AC brushless motors that do not have Hall-effect switches. To use the Auto-MSET method, set the Initialization Method of the CommutationInitializationSetup Parameter to Auto-MSET.

WARNING: If you use the Automatic Motor Set (Auto-MSET) method of commutation initialization, the motor moves a maximum of one-half of an electrical cycle when you enable the axis.

The Automatic Motor Set (Auto-MSET) Method:

  1. The process starts when you enable the axis. You can enable axes in the Axis Dashboard Module or use the Enable() function.
  2. The drive outputs current to the motor at a known, fixed, electrical angle that you specify for the AutoMsetAngle Parameter. During the time that is specified in the AutoMsetRampTime Parameter, the current ramps up from zero to the specified value of the AutoMsetCurrent Parameter.
  3. Some conditions can cause Auto-MSET to automatically restart and specify a new electrical angle. If this occurs, it can cause the motor to initialize to an electrical angle that is different from the AutoMsetAngle Parameter. These conditions are as follows:
    • No motion is detected on the axis.
    • Motion is detected into a limit.
  4. The drive holds the level of current specified by the AutoMsetCurrent parameter for the quantity of time specified by the AutoMsetTime Parameter. This makes sure that the motor moves to the specified angle. The level of current that the drive holds must be high enough so that loading, friction, and other opposing forces have a minimum effect on the motor angle.
  5. The drive initializes motor commutation by assuming that the motor is now at the angle specified by the AutoMsetAngle parameter. Then motor commutation continues normally. The drive uses the feedback device specified by the FeedbackInput1 Parameter.