There's no place like home Re: G code

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "ballendo" <ballendo@y...>
wrote:

> In CCED, "Fred Smith" <imserv@v...> wrote:
> > Most controls do have a command for homing. On Fanuc it is with
> > G27, G28, and G29, each with it's own capability.
>
> Hello,
>
> Fred is right. Just want to add a bit about those "capabilities":
>
> Of the three he mentions, only the G27 is really a "home-ING"
> command. Because it is the one that RESETS the machine position
> according to the switches.
>
> The G28 is a RETURN to the home POSITION. (without checking the
> switches. But on many controls there will be "home" indicator

lights

> which may or may not signify having reached the actual--according

to

> the switches--home point. In other words, they may light up

whenever

> the axis readouts are at zero in G53--the machine coord system.)
>
> And G29 is a return FROM the home position. (again without
> any "check" of the position.)
>
> Both G28 and G29 usually allow an intermediate point to be
> included "on-the-way" to the home position. This is used to stay
> clear of the work or work-holding devices.
>
> There are a few controls which use an M code for homing, and it is
> often a high number like M101.
>
> And on some controls, you could set up a homing routine using the
> macro language, and then alias it to a given G code...
>
> Hope this helps,
>
> Ballendo

I get the feeling that everyone who is participating in this thread
is not talking about the same thing when they mention HOME.

One of my machines has HOME, REFERENCE, and may have a part ZERO
position. The HOME and part ZERO are user specified. REFERENCE
position is determined by hardware. At various times I've seen all
of these called HOME. So which are you guys talking about?

Doug