Mach2 remembering position after shutdown..how does it know

[Moondog]

Hello guys.

I have the machine working.. have yet to set up home switches.

My question is:

After I have finsihed for the day I set the machine about in the middle. The DRO's note the position. After switching everything off and then re-starting Mach2 doesn't rememebr its last position and I have to re-set the Zero positions.

I know home switches tell Mach2 where home is, but...

But if you switch a machine on and it doesn't know where it is...how would Mach2 even know which direction to start looking for a home switch.

For example... if the machine was at the X+, Y+ extremes on startup and the DRO's all show Zero.... how does Mach2 know which direction to go?

Is there so way of locking the DRO's/position on shutdown?

cheers

Frans

[CNCadmin]

You should be able to set the direction of travel towards the limit switches. So when you hit the home button mach know which way the axies must move to hit them.

[ger21]

Look under Config>Homing, under the section "homing direction".

[Barker806]

If you would like it to store your last position (On power down) you can check the copy G54 from G59.253mon start up under the config/state menu. as for homing it will go + or - dir and it matters not where it is on power down or up.

Hope that helps
Brian

[sol]

I think this is what you want though Art warns that it does not guarantee exact positioning.

Config>Logic configuration> Persistent DROs
There is a check box for it.

Explained in MACH 2's new manual, page 5-25

[ger21]

Explained in MACH 2's new manual, page 5-25

Otherwise known as 5.8 in the index.

[Moondog]

Thanks for your help. I'll give your suggestions a try.

Many thanks...

[ynneb]

After every cut the gcode will return the machine to zero. If you turn on mach2 in the mornings it will assume the axis are at zero, and it will be. You just have to set the Z axis only.
If however you bumped your machine while it was off your zeros would be out, and it could cause all sorts of dramas.That is why it is wise to either have zeroing switches or just set up all your machine each morning.

[JRoque]

I forget the exact term but Mach2 has something called "persistent DRO" that will store the last location before it quits. Next time you launch it, it loads these values to the DROs and you're set. Of course, keep in mind that there's a good chance the position will change when you remove power from your motors so keep that in mind.

JR

[buscht]

FYI, All the professional CNC routers that I have used require a homing operation to zero out the axis before you can run the machine. Once a day, or once every time you turn the machine on.
Too many things can happen when the machine is switched off to guarantee positioning accuracy.

[ger21]

I can push my 1000 lb cantilevered gantry around when the machines turned off. And, if the router is at the far corner when I turn it off, the dust collector hose will actually pull it when the machine is switched off. So you never really know where it's at until you home it.