Re: Slowing down quadrature encoders


<ringo.davis@xxxxxxxxx> wrote
> I have 2 motors with quadrature encoders that I can controlling using
a
> pic16f877a. The problem is that at max rpm the encoders change faster
> than the pic can count so everything goes haywire. This happens

Exactly how fast is that? IOW, how many ints/sec are you getting, or
are you polling the encoder?

> basically when I give a position command and the motor can't move at
> first and then the tension gets released and the motor moves very fast
> (kind of like winding up a spring). I need full power so limiting the
> pwm is not a choice. I have pcb's already made so switching to another
> processor is out also. What I would like is a circuit to divide the

Is it, wouldn't an 18F452 basically drop right in? AFAIK it's
completely pin compatible. It would certainly be faster running at
40MHz.

> quadrature signal down but keep the phase information. I tried a
couple
> 4017 clock dividers but they keep the same spacing between the signals
> in time, not in phase. Anybody have any ideas on an IC or a circuit
> that can do this?

Another PIC or two? ;-)

.

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