I am a CNC newbie. I've been using Mach 3 for months now, but only the most basic functions (load G-code, zero everything, cut, turn off).

Now I am trying to understand bit more about what Mach3 can do.

I wanted to try to setup soft limits and set machine coordinates, so I can't move the machine outside the 'safe limits'. I watched the "Coordinates" video, I setup config on my own machine, and it all worked great. Limits were set, everything was great.

Then I moved the spindle a bit, closed Mach3 and started it again. Machine coordinates were showing 0/0/0, although machine was not at machine 0/0/0 position.

So, the silly question is - can Mach3 somehow remember machine 0/0/0 coordinates between program restarts, so that I don't need to do reference home thingie every time I turn it on?

I guess that it is impossible (how would Mach3 know that I didn't use another software to move machine between Mach3 runs, for example), but it's better to ask than to assume.

Any help is much appreciated

Yes, you should allways ref all home after a shutdown, an e-stop, Or anything else that may confuse Mach (or any other controller for that matter). This is just good machining practice. Better safe than sorry. You can save your fixture offset though. But, the only way to be sure it is at that position, is to ref. all home first, then gotoz.

Brett

Thank you very much for the fast reply.

I will always ref home it, rather than experimenting with saving fixture offsets. Will take a minute or two, but will save me lots of nerves

Thanks once again, much appreciated.

NP  .There is nothing wrong with saving a fixture offset. This is the work coord. The Ref gives Mach a ref. point (0) from there, every move it makes is based on this. If it doesn't truley know where the ref. point is, it can't truely know where the work 0 is.

Brett

Sentinel - it is a big learning curve.

As Chaoticone says - home the machine - however my machine is a lathe, with a milling head attached. The home switches are with the table ( which on the lathe carries the cutting tool, but on a mill it carries the work piece ) to the left just under the chuck, and as far towards me as it will come (without disengaging the lead screw).

Neither of the home positions is ideal for the starting position for either the lathe or the mill. This is where the offsets come in.
The HOME homes the machine co-ordinates to 0,0. The offsets then move the machine to the starting point for working (on mine there are at least two different ones) and then zero's again. This, as Chaoticone says, is the work co-ordinate - the point that your program calls 0,0. It can be a different position for each type of job.

The next thing is the tool offsets !!!