Centroid Community CNC Support Forum

Ok so here it goes.

When I use the MDI how do I get it to use the machine position and not the WCS? I thought before that when you hit Alt D and you see machine up top and on the dro that your moves are with in the machine coordinates.

What is happening is it will only move to the WCS. I'm not at the machine but I think it's G53? Maybe G54? I don't remember. For some reason I thought before even if there was a value set in the WCS for one of those, that when I toggled to Machine and used the MDI that it would move with in the machine coordinates. What it's currently doing is only moving within the WCS when Machine is selected, unless I zero out the first WCS G53?/G54? don't remember the first one. I looked around for what the call out is for the home Machine position but came up empty. I'm sure it's as simple as entering what ever the machine position is in the MDI prior to entering values for the movement. I just don't remember having to do anything other than toggling Alt D to Machine.

I'm sure I'm confusing with my post, writing isn't my strength.

As always any help would be great!!

Dan

been running cnc since 97. never need this stuff but i was wondering how it worked so i was just messing with my mill. if you use a G28 it will go to wcs coordinates then machine home. kind of strange. G53 it goes straight to machine coordinates programed.

What are you trying to accomplish?

Just messing with it some more. if i mdi a g28 z0 x0 y0 it seems to go straight to machine home but if i mdi a g28 z-1 x4 y-2 it goes to these coordinates in the current wcs then to machine home.

Some clarification (much of which you have probably figured out already):

1) Alt-D only changes the basepoint for the DRO display. It has no effect whatsoever upon the current work coordinate system, or upon how G code commands are interpreted.
2) G54 - G59 are modal coordinate-system selection codes. They change the active work coordinate system.
3) One or another of the local work coordinate systems is always in effect. You cannot "cancel" G54 etc. and somehow revert to machine coordinates.
4) Ordinary moves (e.g. G90 G0 X_ Y_ Z_) are always referenced to the active work coordinate system.
5) G53 is not a modal coordinate system selection. It is not like G54 - G59.
6) Instead, G53 is a one-shot Rapid move (performed like a G0 move), which is always referenced to machine coordinates (and, therefore, unaffected by the current coordinate system selection).

So basically all I'm trying to to do is move my machine around with in the machine coordinates using the MDI. The problem I was having is I have a G54 setup and I wanted to be able to get back to the machine location and use the MDI instead of using the jog panel. Basically what can I enter in the MDI so it will recognize the Machine location and not still be in the WCS? If I zero out the WCS than it works, but I don't remember having to do that before. Maybe I wasn't using G54, I honestly don't remember since I hadn't cut anything in a while prior to doing the 4.14 update.

I'll post some pics when I get back to the machine so it will be clearer what I'm talking about.

Thanks everyone,

Dan

Type G53 X(coord)Y(coord) into the MDI

Gary Campbell wrote: ↑Sat Mar 23, 2019 8:22 pm Type G53 X(coord)Y(coord) into the MDI

Thank you Gary, I couldn't remember how to get back to the machine coordinates. I'll try it out later tonight when I get home.

Dan

While we're talking the MDI, is there a way to access it while a job is running?

The reason is for the tool touch off where I need to jog to touch off. It would be nice to be able to enter the location in the MDI and have it rapid from the tool change location.

Or would I be better off just trying to modify the macro to do it automatically?

Thanks guys and forgive me for all the questions.

Dan

You could always use another WCS for your tool change position.