Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: birdbrain on July 10, 2008, 04:38:39 AM
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I know this is gonna be simple but I can't figure it out. Where, exactly (which screen, which tab etc.) can I enable the soft limits?
I would love to benefit from the video tutorials which I'm sure cover this but I'm deaf and without sound the tutorials don't make any sense!
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The soft limits are enabled from the main screen, there is a button near the DROs.
You will also need to set the dimensions for your soft limits, this is done from the Config menu then down to the Homing and limits page.
Depending on where your home switches are and what type of machine you have will determine how you set them up but I will give you an example for the normal setup.
For the X and Y minimum you set that to 0
For Z Max you set to 0
X and Y max sre set to the travel for these axis
Z Min is set to the axis travel but it should be a negative number.
You can also set up a slow zone, this is the distance that Mach will start to slow down so that it doesnt overtravel when reaching the soflimits, you will have to find out the perfect distance for your individual machine as all machines will vary due to differences in acelleration, velocity and even machine weight and motor size.
If you are not clear or have a different setup just post again and I will help all I can.
Hood
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Thanks Hood.
That's a big help. Just didn't know where to find the button.
Different subject: ???
Is it possible to reference just one axis to it's home switch?
It's easy to reference "all home" but I have a rotating A-axis that needs to be referenced when stock is changed. I don't always want to re-reference X, Y and Z as well.
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If you go to the diagnostics page you will see buttons to reference each axis individually. If you wanted you could alter the standard screen to have these buttons on the main page or for that matter you could alter the screen and just add one button to reference the A Axis. To alter or make a complete custom screen you use Screen4 which you should find in the Mach3 folder, if its not there then you can get it from the downloads page.
Hood
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Thanks, again, Hood.
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no problem :)
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Hood said it correctly above but i'd like to chime in and add this .... use zero as hood noted, bump your limits in the plus and write them down and use these with enough adjustment for lets say just touching limit without tripping ! then give yourself some decelleration room and set a slow zone that is not too great or small and i used about .200" ! after this is done it is real neetoe in that you can jog right up to your limits without tripping them for whatever reason. one more item ! the softlimit must be off to home referance machine then don't forget to turn it back on ! also after setting all this up and it is working perfect do two more things for assurace. set the "normal function" and then do a full system shut down by the book, no shortcuts, restart and double check function. I found that there are a few things that don't get updated into the xml till mach and pc are properly shut down and resarted, plus i feel much better knowing it is as it should be with PROOF ! MACH is a dream cum true !
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The softlimits dont need to be off to home if you have them set correctly ;)
Hood
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REALY ! If i try to referance home my IH mill with the softlimit active, and mine is set to be active at power up, then i receive an alarm till i turn it off and re-start the referancing proceedure. So, aparently I missed something setting mine up. Could you elaberate some on what must be differant so that it will ignore the softlimit while referancing home. I would certainly appreciate this as it does at times get to be a little agravating when i forget to turn it off or back on after ! Thanks !
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That is because you have not set zero as your min for X and Y and for Max for Z.
The way Mach works is you home, it hits the switches, reverses and then when the switches close again its homed. So your zero position is when the switches are closed. The slow zone is so that when you rapid (or feed) towards a limit Mach will be able to decelerate and stop exactly on zero and not go that fraction further and hit the limits. With a machine with slow acceleration you may have to set up a big slow zone, a machine such as my new mill with AC servos will be able to decelerate from rapid to zero in under a mm I would think so the slow zone will be small on it.
Because you have your min soflimits greater than machine zero Mach will not allow you to hoime with the softlimits enabled. This is because it would have to go beyond the soflimts you have set to get to the home position.
Hood
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AWW ! I understand, I tried to set it up like that at first but it didn't work out for some reason. I eventually ended up where i'm at now. As i recall i ended up on the wrong side of the limit switch and faulted ! but it was quite a while back and i disremember details ! Actually tho, i like it this way. I don't need the soft limit set exact at zero and i can run up to soft, turn off soft, re-ref home, drive off limit, turn back on and run from there if i have a questionable situation and need to dbl chk ref. So, I think i'll leave well enough alone and keep my yap shut for a while again, As i recall it was really touchy setting up that way as it must be accurate all the way down to the nannobuthair or it will fault out. And my presant setup works for me ! I can see tho that if set exactly that your way would be smooth too ! Thanks Hood and keep up the good work, your a definate possitive influance here and i do indeed appreciate all i see from you ! CHEERS !
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Cruiser
If you set up a slow zone it will not stop at that point, it will just start to slow down when it reaches the slow zone but will continue at a reduced (and reducing) rate until it reaches the zero position. The easiest way I found to set the slow zone was to set it quite large at first then jog away and then jog back at full rapid and see if it hits the limits, if it doesnt reduce the slow zone and try again. You will soon find out where your best position is. If you set it too large you still wont compromise table movement, just it will start to slow down sooner.
If you decide that you want to keep it your way then I think you could probably edit your Ref All button to disable the softlimits first, do the Home on each axis, you would then need it to move off the limits by the amount you have set for your min (G28) would do that and then finally enable the SoftLimits again. That way you wouldnt have to remember to re enable the softlimits after a home move.
Not tried it as the way Mach does it is good for me but if I get a chance I will try it and see.
Hood
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Cruiser
If you want to keep the setup you have you can put this in your RefAll button and test it out. Seems to work fine here but be aware I am not a VB Ghuru so be ready with the E-Stop just in case ;)
You will need to go to the Homing and limits and set values in the G28 box for each axis you have, the values will need to be whatever your soft mins for X and Y and SoftMax for Z are set to.
The VB should look to see if the softlimits are enabled if they are they will turn them off, then will reference each axis in turn and then move to the G28 position before turning the SoftLimits back on. If for some reason the Softlimits are off it will do the homing, move to G28 position and turn the SoftLimits on.
Hood
If GetOemLED(23) Then
DoOemButton(1029)
DoButton( 24 )
DoButton( 23 )
DoButton( 22 )
DoButton( 25 )
Code"G28"
While IsMoving
Wend
DoOemButton(1029)
Else
DoButton( 24 )
DoButton( 23 )
DoButton( 22 )
DoButton( 25 )
Code"G28"
While IsMoving
Wend
DoOemButton(1029)
End If
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When I test if my machine will really stop at exactly 0.00 or my max, it kinda works. For example I move the x axis to the right (starting for 0.00), it moves, as well as the DRO on MAch3, then when I move it to the left, (back to the original position which is 0.00), it doesn't move. It just stays on that position, while the DRO moves to 0.00. SO yeah the limits work and stuff. But it doesn't apply to the machine.
When I try and do it again, the 0.00 position is not on the old place anymore since I moved it to the right and it didnt go back, SO it just keeps moving to the right and not moving when i move it to the left, but Mach3 is thinking that it moved to 0.00 when in reality it didnt. So the motor just kept moving right without going back.
This is happening to all the axes.
Oh and it says on the bottom
"Soft Limits System Movement Aborted"
Any ideas?