Re: rotary hand encoder wheels with detent

Hi Sean,

I wondered about that. .000125 results in a single step, whereas .0001
is not. Perhaps .00025 would be better, two 1/2 steps (Sherline).

I see you point about limiting the travel on a full spin, but as I
currently also set a jog rate and use an incremental encoder, spinning
the knob fast will "loose" the handwheel steps. Using a DRO chip would
"save" these steps, something I'm intending to experiment with.

When using the keyboard keys to jog, holding down a key will continue
the jog. With the encoder and a DRO chip, something similar could be
done.

I have observed that with larger jog sizes, more jog rate is
appropriate, and what I'd really like to do is make the rate dependent
on the distance to be traveled. The rate would have to map at both
ends. Slow enough at the low end such that single steps could be
traveled for "touching off", and fast at the larger end so that motion
would be more continuous.

Alan KM6VV


audiomaker2000 wrote:

>
> Hi Alan,
> Too many.
> Your jog increments should be...
>
> .010
> .001
> .0005
> .0001
>
> Anything less is silly and anything more is dangerous. You don't want
> to be able to travel 20 inches with a revolution of your wheel.
> What is done instead is having a jog "continuous" where you hold an
> axis jog key and it keeps moving at the set jog feedrate. This allows
> you to move larger distances without spinning the wheel. Imagine the
> acceleration of a jog wheel you could spin revolution in .1 seconds
> when set at .1" per increment (100 increments would equal 10 inches
> per revolution). That's un-necessary, un-doable by most motors, and
> dangerous.
>
> Sean
>
> --- In CAD_CAM_EDM_DRO@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:
> > Hi Fred,
> >
> > I've been trying these step sizes, too many?
> >
> > 0.200
> > 0.100
> > 0.050
> > 0.020
> > 0.010
> > 0.005
> > 0.002
> > 0.001
> > 0.0005
> > 0.00025
> > 0.000125
> >
> > Although the Sherline and stepper motion hardware isn't accurate to
> the
> > smallest step size, it seems necessary if one wants to creep up to a
> > surface, to set a zero on a part.
> > Too many choices? I "rotate" through them with a push of a PB, or
> as a
> > menu, with the cursor keys. This list is used by both the pendant
> and
> > "cursor key" jogging (pendant and keyboard jog are NOT available at
> the
> > same time).
> >
> > Currently I am playing with a 256 cpr encoder, because that's what
> I had
> > on hand. A Sherline knob pressed into service has 50 divisions,
> so I'm
> > thinking that might be a good choice. Now to work in the detents!
> I
> > have a "DigiKey" 24 cpr encoder (read by a PIC) on a "radio"
> project, it
> > has detents, but there is a fair amount of drag on it, doesn't
> spin, and
> > is not as nice as the 256 count encoder. More experimenting
> required!
> >
> > Alan KM6VV