Zero axis after jogging ?

[epineh]

Hey guys, I am trying to work out how to zero an axis after jogging, so for instance I clamp a piece to be milled onto the table, jog the machine to what I feel is the 0,0,0 point and reset all axis (or only one if that is all that is needed).

I am used to using DeskCNC and with that you just click on a button beside the DRO to do this but I cannot see how to do so in EMC. Read the manual and there is no mention of zero'ing an axis.

Russell.

[epineh]

Never mind, I got onto the #EMC IRC channel and got it straight from the top (cradek)

Russell.

[unterhaus]

what's the answer?

[epineh]

Its a secret...heh not really, he said to use the touch off button and accept the default of zero, sounds simple enough, haven't tested it yet but hopefully soon.

Russell.

[sansbury]

Russell, could you post a little more detail on this? I'm interested in building a Z-depth touch-off sensor and while I've seen how to do this in Mach, EMC is still really opaque to me.

[epineh]

Sorry Sansbury but I haven't really got anything going yet, I am currently building the servo drives so I cannot really play with EMC just yet, I have the DRO updating on screen by turning the leadscrews but without the drives operational I cannot do much more.

Hopefully in a fortnight I will have it operational.

I definately want to build a touch off sensor myself so I will be trying to work it out just as soon as the machine is going.

Russell.

[samco]

You can hook the switch to the probe input of emc. (you will have to hook it up in your hal file to whatever pin in the printer port your using - assuming your using the printer port .) Looking at this program

http://cvs.linuxcnc.org/cvs/emc2/nc_...ngth-probe.ngc

gives you an idea of setting tool lengths with that switch.
(it has nice comments in it)
sam

Originally Posted by sansbury Russell, could you post a little more detail on this? I'm interested in building a Z-depth touch-off sensor and while I've seen how to do this in Mach, EMC is still really opaque to me.

[cyclestart]

AHHa ! Was just about to ask if there were examples of TLO switches in emc. A member here named Bubba (I think) has a blog with a Mach example.

To the original question, zero can be punched in as "touch off" if the machine is at the intended x0,y0. If using a pin or edgefinder, punch in the measuring tool radius +/- accordingly.

In axis, click on Machine->show emc status
This will pull up some useful information on position. Somewhere in your emc folder the is a file called stepper.var. Play around with the touch off and see how the lines 5221, 5222, and 5223 in stepper.var match the touch off position. Line 5220 needs to be 1.000000. These are the same lines used for offset G54 btw.

G54 thru G59 is the way I'll be programming as soon as my home switches are setup. Line 5220 in stepper.var can be 1.0000, which corresponds to G54. A 2.0000 would activate G55 which uses the lines below 5223 etc.

Just a bit of FYI. Hope it helps in someway.