Re: [CAD_CAM_EDM_DRO] Quadrature?

In a message dated 22-Mar-02 02:50:45 Central Standard Time,
scotr@... writes:

> Quadrature. So, what is it? And how should I approach it when starting
> to set up a dro?

Scott: Surely someone much wiser than I will answer this more "properly",
but here's THIS ignernt old troll's answer to your question: "Quadrature"
means when two "square-wave" signals are 90° out of phase with one-another.
That is, the second channel (wave-form) CHANGES only when the OTHER channel
(wave-form) is stable.

These two signals (channels, wave-forms) are usually named "A" and "B". If
"B" makes a transition from LO to HI when "A" is LO, then the (UP/DOWN-)
counter counts 1 "UP". If "B" should make a transition from LO to HI when
"A" is HI, then the (UP/DOWN-) counter will count 1 "DOWN". This way, the
"electronics" can tell whether the encoder producing "A" and "B" is moving CW
or CCW.

It'd be much easier to explain "face-to-face" with a sketch-pad and pencil,
but I am sadly too ignernt to do it here.

If you have similar straight-forward questions about such simple stuff, feel
free to e-mail me direct.

Jan Rowland

P.S: This technology had me addicted, years ago, and I delved into it until
I learned a little about it, and THEN I discovered STEPPER MOTORS, and how
SIMPLE they made things. As I had (nor now have!) ambition to get into the
wonders of servos and encoder magic, I stuck with simple steppers in building
my own home-brew CNC toys, and I have never regretted it!


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