Galil Motion Control

In systems with absolute encoders and brushless motors that are being driven by a sinusoidal drive such as the D3540/D3640  or DMC-30012, you can take advantage of the absolute position information  to commutate the system at power up without using BX or BZ.  Instead, you can measure the phase relationship and then run a #AUTO routine using that relationship to automatically commutate the motor

A majority of motion control systems that include feedback will use an incremental encoder. The draw back to incremental encoders is that upon power up the controller does not know the position of the motor in absolute terms. To compensate for this, system engineers will home a system upon power up by driving the motor to a switch at a known location.