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Motor Phase-Finding

Phase-Finding Procedure

  1. The drive has previously been configured (via its drive parameters) to commutate using phase-finding.

  2. The drive shall signal that phase-finding is required using the Warning bit. The application program notes the fault and uses the Warning_Read service command to detect that the Phase_Finding_Required flag in the warning register is set (the code returned by Warning_Read is manufacturer-specific).

  3. The network is cyclic and the drive processor is phase-locked. The motion controller continues to disable the drive by setting AMPEN_flag=0, this also causes the drive processor to set Autonomous_Drive_Action_Complete =0.

  4. A call to the MPI function mpiMotorPhaseFindStart(...) will cause the following sequence:
    • The motion controller configures the drive to carry out the autonomous action (phase-finding) using the Set_Autonomous_Drive_Action_Type direct command. A drive may support several manufacturer-specific methods.
    • The motion controller’s control law is suspended, and the Drive Demand is set to zero.
    • The motion controller enables the drive (i.e. the AMPEN pin / AMPEN_Flag becomes true) signaling the drive to begin Phase Finding.

  5. The user application will monitor the status of the drive through the MPI function mpiMotorPhaseFindStatus(...).

  6. The user application has the option to abort the phase finding sequence at any time through the MPI function mpiMotorPhaseFindAbort(...). This method will
    • Cause the controller to disable the drive, immediately halting the phase finding procedure.
    • Return the drive to its original state with the phase-finding Warning bit set.

  7. To monitor the Phase-Finding process mpiMotorPhaseFindStatus(...) will return
    • If the motor is still phase finding: state = IN_PROGRESS.
    • If phase finding is successful: state = SUCCESS and msg will be filled out with a drive specific code and string which reflects how successful the Phase Finding routine was (see Direct Command 0x63). The drive will be disabled and ready for normal operation.
    • If phase finding fails: state = FAILURE and msg will be filled out with a drive-specific code and string with information as to why the process failed (see Direct Command 0x62). The drive will be disabled with the Warning bit set and another attempt at phase finding will be needed.

Phase Finding State Diagram

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