Re: [CAD_CAM_EDM_DRO] Basic Stamp + Encoder

Depending on usage, the stamp may be too slow. The fastest version on the
Parallax WEB site appears to execute 12,000 instructions/sec. You are going
to want to trigger two simultaneous A/D conversions, read the results,
perform the necessary arithmetic, and then do something with the results.
This is going to take several instructions.
Assume 10 instructions per conversion (which is probably low) and 2048
conversions per revolution:
(12,000 instructions per sec / 10 instructions per conversion) =>1,200
conversions per second.
1,200 conversions per second / 2048 conversions per revolution => 0.586
rev/sec
0.586 rev/sec * 60 sec/min => ~35 RPM (assuming my arithmetic is correct)


There is an interesting Application Report on the Texas Instruments WEB site
that discusses resolver to digital conversion. The title is "TMS3240F240 DSP
Solution for Obtaining Resolver Angular Position and Speed". It's 23 pages
of useful reading. It doesn't appear that the associated code is available
(at least I haven't found/recognized it yet).


Analog Devices has a resolver to digital chip set that might be interesting.
It outputs position in digital format plus quadrature encoder signals. One
chip provides the reference signal, the other one channel of data. The
reference signal could drive multiple resolvers. Last time I looked IIRC
three chips totaled around $125 US.

----- Original Message -----
From: "wscalione" <wscalione@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Saturday, June 29, 2002 6:02 PM
Subject: [CAD_CAM_EDM_DRO] Basic Stamp + Encoder


> Has anyone ever used a Basic Stamp to read quadrature encoders?
> If so, I'd be interested in seeing how you did it
>