[Robotgroup] Processor with Hardware Encoder Support

[Dave Hylands]

Hi Vadim, 

> I want to use encoders on the motor shafts rather than the 
> (geared) output shafts.  The reason being that with reversal, 
> gear backlash results in lag and deadband, and will cause 
> instability in a closed loop position control feedback path.  
> Using a 5000 RPM motor with 64 count encoders for instance 
> would be 320,000 counts per second.  That's a lot of time to 
> spend in interrupts.  Admittedly it is probably more 
> precision than absolutely required, but these are realistic 
> numbers for how a motor with encoder comes equipped.  That 
> plus I have several such motors, with 100 count encoders I think.

If you're interested, I have some LS7366 quadrature decoder chips for
sale on my web site. I still haven't gotten around to using them, but I
ordered 50 to get a good price:
http://davehylands.com/Store/us/

They require an external clock or crystal to operate (see the data
sheet) and have an SPI interface.

--
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/