Re: [CAD_CAM_EDM_DRO] Limit and Homing switches

Hi Drew,

You could be right, but as long as you just need the index to happen,
and not STAY valid, then it should be OK, IMO. I'm not totally clear on
this, but essentially you can't "use" the uSteps as INCREASED
resolution, just "S M O O T H E R" motion.
Are you sure you need the index to stay on (not just the event)? And
also, how many encoder "steps" do you have? That has to figure in.
Isn't that the STEPS you command with? So I'm thinking you command 5X
(encoder) steps, and it moves. So you can stop on one encoder step,
right? Or am I all wet? The microstepping should be "inside" these
steps? No? Wouldn't you get an encoder step that is 5 microsteps
wide? I may not have this right, so we need to get clarification on
this!

I think there is more to a G340 then I understand. Yeah, I KNOW there
is! That's why I want to try servos... although I have LOVED playing
with stepper motors sense first seeing them in about '77! They spin up
pretty fast you say? Humm...

Alan KM6VV


Drew Rogge wrote:

>
> I'll put the scope on the thing and see if it wiggles. The problem that
> I foresee with the X5 is that for every step the software issues, the
> motor is going to turn 5 quadrature counts worth of rotation. If the
> index pulse only occurs every 4 counts of rotation then it's possible
> that index pulse could happen in the middle of those 5 counts and not
> be asserted when the step is done. Things would probably be worse if I
> was doint X10. I guess I'll just have to try it and see what happens.
>
> I think you'll find the servo stuff a lot of fun. It's neat to see them
> spin up pretty fast.
>
> Drew
>
> Alan Marconett KM6VV wrote:
> >
> > Hi Drew,
> >
> > Encoder parts (PCB's) are often built so they "could have" an index, but
> > the extra parts may not be there. Hang a 'scope on it, and look! If
> > TTL, you could probably get by using an LED and 220 resistor to +5V to
> > "see" the index (very narrow). Move slow, and see if you can see find
> > the index.
> >
> > I wouldn't think the 5X of the Gecko would come into play, but rather
> > the resolution of the encoder. I know, let's ask Mariss!
> >
> > Sorry I can't be of more help. I'm anxious to get a pair of G340's and
> > try out some servo's stuff myself!
> >
> > Alan KM6VV
> >
> > Drew Rogge wrote:
> > >
> > > Hi Alan,
> > >
> > > I was wondering if you could check me out on something. I'm currently
> > > using servo motors with Gecko G340's. The encoders have an index pulse
> > > (or at least a pin for one, should check that out I guess) and I was
> > > hoping to use some sort of an AND gate to generate the home signal. I
> > > think I may have a problem though because I'm using the G340's at a
> > > X5 multiplier. For some reason I think this means the index pulse MAY
> > > occur between "step pulses" from the computer. In other words it may
> > > be the case that the index pulse happens "between" step pulses. Has
> > > anyone else tried to use an index pulse with G340s in something other
> > > than X1 mode?
> > >
> > > Drew
>
> --
> Drew Rogge
> drew@...
>
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