Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: swanner on September 08, 2011, 10:08:43 PM
-
I am using a 3 axis router, and the Z zero is at the top of the Z axis, I have the soft limit set at .4". The tools are offset to the spoilboard, so all the Z moves in the g-code are -.005 or more, rapiding between 1"-2" depending on material. I'm getting a warning before running every program that the Z is out of soft limit and if I want to continue, the programs run fine. How do you keep the soft limit enabled on the Z axis without getting this warning every time?
-
You have a min and max for the SoftLimit THEN you have a slow down zone. What settings have you got for the slow down zone?
The reason you are getting the alert is that you are in the Z zone.
Just a thought, (;-) TP
-
The safe max is .4; safe min is -7.5; slow zone is .25 - the machine never leaves that range or goes into the slow zone but I still get the warning.
-
I think you have your settings reversed.
(;-) TP
-
I don't think I do, if I reverse them soft limits won't turn on. I have run the machine to the end of all the axis and they work as expected. I've attached a picture of the limits setting screen and also what code looks like. My tools are touched off to my vacuum table and the Z work offset is used to define pod or spoilboard height (.5"-2").
Is it not calculating the work offset in the program? Soft limits stay on when I run the program after the warning, but are they now disregarded? If the program is actually going to move past the softlimits will the soft limits stop it?
-
OK i had to go back and play with it it has been a LONG time since I played with it last.
You are correct in your settings. But remember those settings are in Machine Corrds not work coord. You may want to reset the Zmax to a value below Zero as Zero is normally the machine home position and it will trip the limits before it gets to the softlimit.
If you load up a program that violates the softlimits then MACH will warn you with "SoftLimits WARNING" AND the LED stays on BUT If you continue it will limit out and stop.
(;-) TP
-
Actually I would set the Zhome to be about .25" off the switch location. Then set Z max .1 that gives you a small buffer so when you send the Zhome it will not trip the limit or hit the softlimit.
Just a thought, (;-) TP
-
You should not have a negatiove value for X and Y Min and a positive value for Z Max.
As Terry has said they are machine coords so should not be past the axis extent, ie X and Y min is always Zero and Z Max likewise (on a conventional machine before someone chimes in ;) )
You can if you wish have the values slightly on the positive side for X and Y and Negative for Z but then you may need to disable SoftLimits before homing (depends on settings) Personally I always have them as machine zero.
Hood
-
I'm not quite sure what you're suggesting to change. The home switches are all 0 in the machine coords, on the Z that's almost the very top of the ball screw, .65 is the exact end of the Z axis in machine coords. The only time the machine homes to Z0 besides homing is in the very beginning or end of a program, during a tool change, but it goes to Z0 in G53, never going any higher than Z0 in the machine coords.
There is no physical limit switch on any of the axis, at least not yet, I plan on hooking them up eventually this is just home the machine came. The rest of the coords I've entered for soft limits work as well, slowing and finally stopping right up to the hard stop, unless the machine is really lost then it shouldn't have a problem homing with the soft limits on, it works with them on now.
I don't quite understand what you guys are suggesting I change - the home offsets where there is all zeros now or physically moving the switch?...
-
You can set a Home Off value equal to the distance the Home switches are away fromaxis extent. That will mean when you home the Z for example will be set to 0.65 letting Mach know the position of true machine zero and that way you can set the Soft Limit as 0 for Z Max. Similar for other axis.
Hood
-
Doing that means I would have to adjust all the locations in my tool change change script and touch off, right? And then I would also have to edit my post because the Z0 moves would be at the soft limit, through the safe zone. I had just test run a few programs before reading this and nothing in the standard g-code in every file causes the machine to go near the soft limits yet I get the warning every time.
-
Attach your code, your tooltable, offset table and xml and I will see if I can figure it out. Tooltable and Offset will be found in the macro folder then in the folder of your profile, they are called tools3.dat and fixtures.dat
Hood
-
Testing here IF I violate the space then I get the warning IF I stay in the boundaries I do not.
SO can you post an example of a short program that causes you problems? Easy enough to test.
YOU Have the lead on this one Hood. I'll stand by.
(;-) TP
-
Here's the attachments. I tired using the home offsets, see picture attached of the settings I used. It still didn't fix the warning message, the only way I can get rid of the message besides turning soft limits off is move the Z max to say 3, it just doesn't appear to be calculating tool offsets when reading the program before running it.
-
Forgot to include the g-code in the zip file, but if you look back at my third post in this thread you'll see the .nc file attached.
-
You have some weird things going on in Ports and Pins, for example you have the Home switches set up to port 1 pins7, 8 and 9. They are OutPuts on Port 1 but maybe you have some other type of hardware that can share pins?
Hood
-
Just a note BUT the gocde has the Z running ABOVE the softlimits zone.
Justa thought, (;-) TP
-
Ok just found out you are using Industry Control Software with the MCB1 and really you should be getting support from them as your xml wont run on Mach3.
I did load your xml, tool table etc into IC and loading the code didnt give me a softlimit error but afraid I dont have the MCB1 so cant test things properly.
Hood
-
Thanks, guess I will taking this thread to their forums then. As for the g-code running above soft limits - it does not. It looks that way because with tool and work offsets applied Z0 become the top of the spoil board/bottom of material, so besides the -.005 cut through depth, all the Z moves in the g-code are positive values. When the g-code returns the Z axis to 'home' it uses G53, disregarding the offsets and staying clear of the soft limits.
-
OH but it does , You are using the the inverse z method where all your moves are positive instead of negative. That is backwards to conventional useage. You now have 2 homes that move in opposite directions of each other(;-)
IF you set the Z zero too high off the table OR use a tool offset that moves the Z into the machine Softlimit zone it will trip.
(;-) TP
-
Do you mean if I used a tool that was too long, or a z clearance that was to much, or material that was too thick? Wouldn't that be the case with any way you set it up? I say this because the program runs fine the way it is setup and programmed, everything works, I was just getting that warning. I think I have it fixed, I received an updated version of the mach3.exe and it seems to have taken care of the problem, ran two programs and no warning message. Thanks for the help.
-
That would explain why I never saw the warning as I was using the latest IC version to test.
Hood
-
I ran the Gcode in Mach3 and never saw the warning UNLESS I moved into the controlled zone. IF I Refhome the machine then offset the work coords to where they should have been it ran fine.
Just a thought, (;-) TP
-
Well thanks for your time and assistance. I've been running the machine this morning and everything is working as it should.
My next endeavor will be editing my tool touch off script so that it touches off twice and compares the numbers against a tolerance value I can set; if it's over the set value than its stops and I get a message informing me of the discrepancy. I'm hoping it's been done before and I can find some code to work off of, I have no idea where to start.