Re: [CAD_CAM_EDM_DRO] Home /limit switches

Jon Elson wrote:

> Robert Allen & Marsha Camp wrote:
>
> > Anyone have a recommendation for high accuracy home
> > switches, will regular micro switches work? I have CNCpro
> > which apparently goes to the switch then backs up a set
> > distance so the home switch must be repeatable to at least
> > .001" I would think maybe closer.
>
> You may want to add a second sensor, probably an optical
> 'slot' sensor that detects a disc with one slot on the motor.
> An and gate can combine the coarse switch and the fine
> sensor to get a more repeatable position.
>
> Jon
>

I think the encoder has an index mark (ch. A, ch. B and I) but I don't think
CNCpro can use it.
I wonder if there is a way to use it. I don't quite see how I can get
movement back to the index mark without building some kind of circuit that
stops the input to the gekkos when the home switch is reached and the table
backs up a set distance.
I would have to set the back up distance to go further than the index mark
and stop the gekko input, how, a transistor shorting the input from the
software high or low as needed. This might be accurate if the homing speed
was slow enough. I see this getting a lot more complicated than I thought it
would be.
Thanks Bob
KB1FRW