Re:Home Switches

First, opticals are the way to go, hands down.

The problem you're experiencing is more than likely because the home
is referenced durring the back off phase of the home. So although
the contact is repeatable the "unclick" is not. One way to deal with
this is to put a "one shot" on the home switch. It allows you to
give a percise pulse on the click. It would incorporate the function
of a de-bounce and an auto back off in one $2 circuit.

Just somthing to think about.

Thanks
Aaron Moss
www.IndustrialHobbies.com



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Dave Fisher" <dave@d...>
wrote:

> On fitting home switches to our router table, I notice that each

time

> I home the table - the X and Y readings differ greatly, some times

upto + -

> 0.5 mm. Seldom never going to zero. Slowing the home traverse speed

seems to

> make little difference.
>
> I would have expected there to be some differnces caused by

backlash etc but

> not as much as I am getting.
>
> I have used good quality lever type micro switches, but wonder if I

am

> suffering from switch bounce or just the mechanical properties of a

micro

> switch. Would I be better using a slotted opto coupler to eliminate
> mechanical tolerences or any other method ?
>
> The table is being driven with Rutex Amps and The Desk CNC sofware

and

> controller.
>
> Any advice would be appreciated
>
> Rgds to all
>
> Dave Fisher