Wake and Shake Overview

Motors which have no way to automatically identify commutation must run Wake and Shake. Motors without hall effect sensors fall into this category, as well as motors whose hall effect sensors were manually installed, and not aligned to a motor phase of 0 degrees.

The drive will determine if Wake and Shake is needed for safe operation based on feedback type. If needed, the drive will automatically arm Wake and Shake for an axis. If Wake and Shake does not complete, a fault will be generated. When that fault is cleared, Wake and Shake will be automatically armed again.


  • If the user attempts to manually disarm Wake and Shake on an axis which requires it, a fault will be thrown when the axis enables and Wake and Shake will automatically arm again.

     

    If Wake and Shake is armed for a motor with a feedback type that does not normally require Wake and Shake, the algorithm will still execute. If Wake and Shake fails, a fault will be generated. After the faults are cleared, Wake and Shake will automatically arm again.

     

    If Wake and Shake has been manually armed, it can be disarmed by clicking on the "disarm" button on the Wake and Shake screen, or by executing the AXIS#.WS.DISARM command over telnet.

     

    Wake and Shake is not compatible with Gantry Mode - if any axis is configured with Gantry Command Source, if Wake and Shake is armed, a warning will be created (W5515) and, if Wake and Shake is started, a fault will be generated (F5515).

     

    The drive requires AXIS#.IL.OFFSET to be zero while performing wake and shake. If your application is a vertical axis or other mechanical configuration which requires a constant torqueClosedTorque is the tendency of a force to rotate an object about an axis. Just as a force is a push or a pull, a torque can be thought of as a twist offset, it needs to be configured after successful commutation is achieved. A warning will alert the user if AXIS#.IL.OFFSET is nonzero before Wake and Shake starts, a fault will be thrown if the user attempts to enable and start Wake and Shake with AXIS#.IL.OFFSET set to a non-zero value.

The drive has multiple modes of completing Wake and Shake, each with different benefits for different operating conditions.

Mode 0:

Mode 0 is the fastest of the Wake and Shake methods. It completes in a few seconds, and is ideal for applications that need a fast start-up time. The tradeoff for this fast execution time is complexity in configuration. There are a lot of parameters that must be precisely tuned for this mode to operate correctly.

For more information see Using Wake and Shake Mode 0 (AXIS#.WS.MODE 0)

Mode 1:

Mode 1 is a more traditional method of completing Wake and Shake. It is also referred to as Commutation Alignment and Pole Locking. Mode 1 takes a little longer to execute than Mode 0, but is easier to configure. Only AXIS#.WS.IMAX (current to be applied) and AXIS#.WS.TSTANDSTILL (time to apply current) need to be configured. The default values work for most motors.

For more information see Using Wake and Shake Mode 1 (AXIS#.WS.MODE 1)

Mode 2:

Mode 2 is the easiest of the Wake and Shake modes. It requires no parameters to be configured (setting AXIS#.WS.FREQ for sine frequency excitation is optional, and the default value will work for most cases). Mode 2 uses an Auto-Commutation finding algorithm that can take as long as 30 seconds to complete. Measurements are taken by exciting the motor with a sine excitation as the motor phase is adjusted. After a series of data points have been taken, a DFT analysis is done to determine the motor phase offset for commutation.