I have never seen one with two reticle tracks, as the usual quadrature out only need one track as the heads are spaced to give a 90deg phase shift. The marker is used for reference or home position, after seeing a home limit switch.
The second (inner band) is too fine for commutation. anyway you would have three motor leads if it was brushless.
Al
__________________
CNC, Mechatronics Integration and Machine Design.
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E. |