Re: Quadrature for DIY DRO

Hi Guys,
If you want to read quadrature encoders directly I would definately
recommend utilising the LS72661 chip from US Digital it's a damn
sight cheaper than missed counts on an expensive machining job. You
can't really read this type encoder reliably without either
dedicating a micro (or CPLD) to this task alone, or relying on chips
like the LS72661.
Scott I have Bascom Basic code to achieve initialising and reading
this chip with an AVR if you're interested (Sorry I don't like Pic's
or more the lack of friendly languages for novices). The big issue
with this type setup is we are now reading a number of "ticks" not
nice convenient numbers as with your scales so there is some work to
do on parsing this data to display it on 7seg LED's. I cheated a bit
here and simply used a large LCD display I purchased cheap, good
enough for my little Taiwanese mill when your looking straight at the
display and a lot less work for a micro to talk to. Boondog.com also
has some good programming starters for the LS72661 chip. In many ways
I think you'll find tackling reading these encoders requires almost a
complete rethink, there's quite a reasonable amount of code required
to crunch the numbers.

Kind Regards, JK