Sorted it out

Just use an output in Mach for each profile - active low, no other use. It comes on as soon as Mach loads and stays on regardless of reset state etc - this output can then control the respective contactor for the VFD needed for that profile.

The supplies will also go through the E-Stop system but this means that the whole startup is now just a matter of clicking on the correct Mach profile

Now, lets look at the Z axis...

I am intending to bolt the aux spindle onto the main quill shaft, this means that my Z travel will be reduced but not drastically i think.

It also means I need two Z home positions - can I use ONE Z home switch at the lower position and use the Z home-offset to tell the system where the home is respective to the profile in use??

Questions-

If i have one home switch in the lower position and the head is already above that switch, what happens when i ref-all??

Is there a smart fix for Z upper limit switch or do I have to try and fit TWO limits switches in at the top??

Getting there

Hmm, bench-top tests seem to look promising - with a home switch offset of 50mm, when i do a ref-all it moves to the switch, stops, moves off, then reverses 50mm. I think that is just what it needs ?

If the switch is already closed when ref-all is called, it just backs off slowly until it opens - nice, BUT the switch trigger MUST be continuous and not just a passing trigger so a long switch cam will be needed there.

Limits??

Rough draft of power wiring and e-stop circuit...

Couple things from a quick look at the diagram, you'll need a limit override switch, and do you really need to have the power for each servo drive use a separate contact?
The same could be said about the ESR relay.

Ooh, good point re the override switch, forgot about that one

No real reason for the multiple ESR, just  the way it evolved, will alter that one.

No harm in having the drives on multiple contacts, its a common style of contactor so no need to combine.

you'll need a limit override switch,

Hmm, thinking on the drive home  , I can see one reason when that would be needed - if the soft-limits fail and the Z axis rams the head right up or down - there is no hand wheel on the Z axis so no way to get it back down again, although I could simply reach up and spin the pulley by hand.

But apart from that, if the X or Y axis runs off the end then they can be rewound before pressing reset?

An E-stop loop would not be bypassed by the limits override so thats ok.

You do have the benefit of being able to move things manually, so you could probably manage without an override button.

I think it would probably be a good idea to wire up your control box to allow for the possibility of adding one later though. Have the limit switch loop come back to a terminal in the control box, before connecting to the E-stop loop, so if you do need to add one later, you've got a nice convenient point to wire one in, with minimal rewiring needed.

Yes i like to wire that way anyway, makes things much easier to trace issues later on when the external stuff comes in on a terminal strip, one by one, no hidden loops etc.

I would like to think that once homing and safe-limits is up and running the only time the hard limits would be it is after a runaway drive and I've not heard of that yet;)

Problem with having lost of I/O available is you soon find things to do with it and end up with one short

Hood

I have a bit more on the MPG module

My list is only about half-capacity at present, plenty to play with