Re: Home switches

--- In CAD_CAM_EDM_DRO@yahoogroups.com, PDJ <pdj@b...> wrote:

> Hi,
>
> I need to add home & limit sw. Can someone explain the difference

in the

> location of x and y limit and home? It seems that x and y are close

to

> the same in position and z is variable. What's the real story?
>
> Thanks,
> Phil

Limit switches are located near the physical limits of the
outer travel limits.
They should be far enough inside to allow the axes to deccelerate
to a full stop before the physical limit is reached.
The amount depends on a Axses maximum speed and decceleration
settings it is typicly about a 0.25 distance in.

Home switches are located within the limit switches so they are
hit first.
They are typicly mounted close to one of the limit switches because
when a machine is first started it dose not know where it is and
by knowing that home is at ether + or - the axes can be simple
directed to go in that direction by the amount of total travel
and will be sure to hit the home switch.
The home switch should be mounted far enough away from the
limit switch to also allow for deceleration of the axes.
This is to ensure the limit switch dose not get triggered durring
a homeing operation.
Home switches are very high precicision switches that can repeatedly
trigger on the same location with a very fast electrial responds time.
They may be mechanic, magnetic or optial types.

Hope this helps
Good Luck