Re: [CAD_CAM_EDM_DRO] Home / Limit switches

----- Original Message -----
From: "Carlos Guillermo" <carlos@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: Thursday, January 25, 2001 2:02 PM
Subject: RE: [CAD_CAM_EDM_DRO] Home / Limit switches


> Les -
>
> I was referring to LPT s/w-type CNC controls that (IIRC) refer to
> having inputs for 3 switches per axis. Do people actually use all
> 3?
>
> Carlos Guillermo

I don't know... I guess that is two limits and a home.

Right now I have one switch and an ACE shock absorber on
each end of each axis. The absorber engages before the switch actuates but
is minimal resistance at low speeds.

I have used optical before.

I guess the fundamental advantage of two spaced switches
is that it gives an "almost home indication". So you can rapid
toward hard or soft home very fast and initiate a controlled
deceleration after tripping the first switch thus avoiding amplifier
limiting or slipped steps.

I would imagine you could do this with one switch as well.
The algorithm would be something like " slow down at a reasonable rate ,
turn around, and hit the switch or index
but do not go further than xxx in the process."

So far I don't have too much of a problem with just heading
to soft home pretty slowly. If I end up turning the thing off and on a lot I
would consider two switches on one end.

I do have a runaway sensor planned and could use that .

Oh on a different note I have a good RH6.2 install!!!!
Now I am searching for linux command summaries on the net.
Then I can tackle the nice 10 feet of printed rt and EMC install
instructions I have.

Leslie Watts
L M Watts Furniture
Tiger, Georgia USA
http://www.rabun.net/~leswatts/wattsfurniturewp.html