I posted a data sheet on the Astria Microsystems AS5035. As i'm using a different motor that has a resolver position encoder I have evaluated different systems to provide the quadrature encoder signals to the controller. This is one attractive alternative to optical encoders.
The AS5035 senses the shaft position using a simple magnet mounted on the end of the shaft. The sensor magnet is mounted with it's poles at right angles to the shaft axis. Internal analog hall sensors detect the field and continuously compute the absolute angle. Output is absolute position (with 8 bit resolution) and quadrature (A,B,Index) at 64ppr.
We currently use the larger version of this device (1024 resolution) for an aircraft engine application and it performs flawlessly. It's designed to operate in harsh environments and high temps.
If any one is attempting to use a non-solectria motor this may provide a solution. I do need to find out if the UMOC will accept 64ppr rather then the 60ppr that is the standard option. If 64ppr will work I'll design the rest of the circuit with appropriate balanced driver to plug into the DB9 connector and get some pcbs made.