z axis Home?

[badgersurfer]

I have just started using 4 Home start points for each of the jobs on my bed. G54 G55 G57 G58. They are working fine but I there is obviously a setting on G54 (Default) that does not exist on the other three.
CAn someone tell me what it is please. Let me explain....
When I go to x,y,z =0 on G54 I manually enter 1.000 in z box, press enter and then click "Goto zero" which pecks my tool down 1mm and then I run the toolpath. When it is finished it returns to zero I then enter my z depth again to repeat the task and each time I do this, the tool just pecks down the amount I enter ready for the next run.
When I run G55, G57 and G58 after I enter my new z amount and enter on the keyboard instead of pecking down each time I click "Goto Zero", it goes to a safe height and then goes down to the new z amount. So basically when I enter "Goto zero" on G54 it goes straight to zero, but when I click "Goto Zero on G55, G57, G58 it goes up to a safe height and then down to zero. Any ideas please and I cannot seem to find the difference between them in the Configuration panel...

[cncdrive]

The goto zero function is coded in the M204 macro file.
The goto zero function moves the Z-axis up first if the axis is lower than the safeZ value in the current coordinate system.
So, it only depends on how much the different working coordinate systems are offset in Z value if the Z goes up to safeZ first or not.

[badgersurfer]

The goto zero function is coded in the M204 macro file.
The goto zero function moves the Z-axis up first if the axis is lower than the safeZ value in the current coordinate system.
So, it only depends on how much the different working coordinate systems are offset in Z value if the Z goes up to safeZ first or not.

My safe z is currently 25 which I am going to change to 5. But I presume that won't make any difference to my problem.
So to clarify this are you saying that if the z zero on workpiece 1 is 0 and the z zero on e.g. workpiece 2 goes to say -1 then it will climb to safe z and then back to z zero on all the other workpieces other than number 1? Is there any way of overcoming this?

[cncdrive]

Zero is alway 0, there is no such thing as zero is -1.
The zero is always 0 in the currently selected coordinate system and the UCCNC uses the currently selected coordinate system to go to zero in that coordinate system.
Check the M204 macro code to understand what it exactly doing, the source code which you may even change is in the Profile/Yourprofilename_macro folder.

[badgersurfer]

I think I have a solution. I have just discovered the popup panel on the left for step jogging as I have always done this manually on the main screen.
This is so much easier. I can now set a common zero to all profiles that is close to the surface and then us the jog panel to go down .1mm and a time. This way it desn't keep going up to safe z and back again but just packs down on all workpieces.

[badgersurfer]

Well I still seem to have an issue that I haven't got my head around yet.
G57 has all xyz coords set to 0. G54, G55, G58 have their xy set to their respective locations. I have placed my tool say 10mm above the work surface and clicked zero for all G buttons so they are all the same. Now if I "Goto zero" on any of the G buttons I specified above the tool will go to their respective xyz zero position. Now if I click "Goto zero" no of them move up to safe z and back, they just stay still except G57 which goes to up to safe z and was originally set to 0,0,0. That's the only difference I can see in the settings. I have looked at M204 for my selected machine profile but I still don't see what is going on here?

Is it this code at the start saying if all DROs =0 then goto safe Z. But if that is the case why when I jog down -0.1 z does it still go to safe z? Or am I missing the point completely.

// Go to Zero with safeZ

if(exec.GetXpos()==0 && exec.GetYpos()==0 && exec.GetZpos()==0 && exec.GetApos()==0 && exec.GetBpos()==0 && exec.GetCpos()==0)
{
return; // if all position DROs are already zero then return
}

OH!!! I have just gone to G57 and jogged x,y 0.01mm and then rezeroed them and it no longer goes to safe z. I need to investigate this further as I still don't get it.

[cncdrive]

If it goes up to safeZ depens on the actual Z coordinate in the actually selected coordinate system.
What is your safeZ and what is your Z coordinate in the G57 system prior to you pressing the Goto Zero button.
If it is lower than safeZ than it will go up to safeZ and will do the homing like that, but if it is not lower than safeZ than it will just go to X0 Y0 and then lowers to Z0.

[dezsoe]

Don't forget, that M204 (Zero all) will first check for all the axis if they are 0. If all are 0 then the macro exits. Next, all axis will be checked except Z if they are 0. If any of them is not 0 only then will M204 decide if it has to pull up Z before zeroing the other axis. If all axis except Z are 0 then only a G0 Z0 will be executed. Maybe, you have some small values in A/B/C axis, while you check only X and Y.