There's no place like home Re: G code

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