View Full Version : Machine zero and Part zero


Regnar
04-28-2008, 05:50 PM
I have read the manual acouple of times and maybe Im not getting it or I cant do it.

I dont have any limit switches but I do put the table back to 0,0. But as soon as a do a part and hit home I cannot goto the left side of the table because its past my soft limits. So I guess my question is this, Is there 2 different zero's one for parts and one for the machine. I hope this makes sense.

I guess I could open up the soft limits to allow me to go back to the tables 0,0 location. But I figured I would ask before doing that.

cyclestart
04-29-2008, 07:33 AM
2 different zero's one for parts and one for the machine.

There is a machine origin and a fixture offset. Machine origin is HOME. Fixture offset is is another set of zeros offset some distance from HOME. Axis provides "touch-off" for creating the fixture offset.

Does this help?
http://www.mail-archive.com/emc-users@lists.sourceforge.net/msg03400.html
the info in that link is an excerpt from a longer explanation found on the wiki or possibly the user manual.

Regnar
04-29-2008, 08:34 PM
Yep thats it. I will probably ask more question tomorrow when I am able to put the text to practice. Thanks for the help. I have looked at that button thinking if I hit it, it would send the Z straight down to the table seeking out a touch off switch.

cyclestart
04-30-2008, 12:59 AM
I dont have any limit switches but I do put the table back to 0,0. But as soon as a do a part and hit home I cannot goto the left side of the table because its past my soft limits.

OOhh, let's see if I'm reading this correctly. You are moving the machine to a HOME position at startup (somewhere at the maximum travel positions) and zeroing the x and y with the HOME button. Then you are completing a part and once again hitting the HOME button, expecting the machine to return to machine origin? Wrong thinking. What you have done is reset the machine origin. If you're MIN_LIMIT (set in the .ini file) is zero it's no surprise the machine refuses to move negative from the current position. This is the soft limits doing their job as expected.

Hope I read this situation correctly. Didn't spot it on the first read through.

Regnar
04-30-2008, 08:03 AM
That was what I was doing. I knew there had to be a better way and everytime I looked up homing it never refered to "touchoff". Im new at this so Im learing as a go along. I probably read the touch off before but thought it was for a touch off probe and paid not attention to it. I went out to the shop and tryed it out and works great now. It even allows me to go into the negative to compensate for tool diameter. Thanks again

Big John T
05-05-2008, 02:53 PM
If you want a "Go to Home" button take a look at my pyVCP Adding Custom Buttons write up on the wiki site.

http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Adding_Custom_MDI_Buttons

John

Regnar
05-05-2008, 04:07 PM
John, You know if I didnt know better I would have said you where in my garage the other day. I was thinking to myself "It would be nice if I was able to hit a button and everything went to home" Well you just proved to me that it is possible. I wont lie to you either but after reading your write up I have alot more reading to do. I dont know what a ini. postgui.hal or .xml are at all. And most of the other writting is chinesse to me to. Thanks again, now back to the book.

Big John T
05-05-2008, 07:33 PM
Some say I'm a mind reader and some say... well never mind.

Hmmm, all those files will be or need to be in your config folder with the rest of your config files. They are all just text files that you can open and read. The .xml file is what tells EMC how to build the pyVCP. The postgui.hal file is a .hal file that is run after the gui (Axis in my case) has loaded. A .hal file is a hardware abstract layer file and it tells emc how to connect things together. the .ini file is what ever you named your config like mymill.ini. If you don't have some of the files just create them. Tell me where you get confused and I'll try and clear up the instructions.

Some useful reading material...

http://www.linuxcnc.org/docview/html//hal_vcp.html


Enjoy
John