Re: Help with Renishaw TP1 Touch Probe?

Thanks for the replys! When using my fluke multimeter (that can read
up to 20 Meg Ohm) I either get nothing, or if I pull on the tip just
right, I can get some contact (the few hundred ohms). Thanks for
letting me know about the max resistance and max current; good numbers
to know! And confirming my assumptions on how it works.

I figured out how to open it up some more. The other side (the side
you can't see in the picture, the one with the rubber boot around the
tip) had a cap that seems to be RTV glued on. I used a razor to
scrape out as much of the glue as I could, then pulled a little and
the cap came off. So at least now I can see inside the thing...

Gotta take care of my day job before I can play with it a bit more.
But now that I can look inside I can get a better idea of what's going
on. This thing is so well made, I can't imagine how it could get so
far out of adjustment. It doesn't look like it's been dropped or abused.

Thanks again,

- Steven Ciciora

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Bill Phillips <cad@g...> wrote:
>
> Steven,
> I had to look at your picture just to work out which probe you had.
> We don't see many TP1's which is why I am unfamiliar with its
> innards. However on a general note you should not expect to see a
> short circuit across the contacts. Anything less than 3300 ohms
> should be treated as a closed contact. When new the contact
> resistance may well be in the hundreds of ohms but as they get
> older/used the contact resistance tends to increase. This is
> especially so if they have lead a hard life. There are three sets of
> contacts which are across DC AB and EF. All three must be seated to
> give an indication across 4 and 5. we recommend a nominal current of
> 0.5ma for maximum contact life.
> The LED is a separate circuit and would be driven directly by the
> interface. 10ma will do nicely.
> Regards
> Bill Phillips
>
<snip>