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Author Topic: Can someone please explain how to use Home offsets  (Read 1501 times)

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Can someone please explain how to use Home offsets
« on: August 02, 2018, 11:17:25 AM »
I am wondering how the home offsets work in Mach 4. I set up a fence on my machine to register my stock. I would like the center of the tool in the X and Y directions to align with the corner of the fence. I have this point set at X = -3 from homing switch, Y= -1 from homing switch. Those values don't appear to do anything.

I have my machine setup with the homing and limit switches being shared.

In the homing tab under setup I have X home offset = -3, Y home offset = -1.

I hit the ref all axis home button. The machine moves until the switches are triggered, backs off the switches (moves about 1/16"  or less), the DRO then displays X=0, Y=0, Z=0.

I would like the position set and the DRO to X=-3, Y = -1. Or the machine to move 3" in the X direction and 1" in the Y direction. How do I do this?
Re: Can someone please explain how to use Home offsets
« Reply #1 on: August 02, 2018, 11:53:43 AM »
That's a good question.  
I would have assumed the Home Offset in the Homing/SoftLimits tab would be have been the place to do exactly what you want; but it isn't working on my end either.
In Mach3 I used the home offset like twice, and the Home Offset is what I used to achieve this.
I wonder if this is a bug that needs to be addressed.
Chad Byrd
Re: Can someone please explain how to use Home offsets
« Reply #2 on: August 02, 2018, 01:00:39 PM »
Not using Mach 4 but try this. The DROs show 0,0,0 because that is where the tool currently is. Try sending the machine home after this and I would expect that it now moves to your desired location, and might or might not set the DROs to zero. Setting them to zero might be needed.
Re: Can someone please explain how to use Home offsets
« Reply #3 on: August 02, 2018, 02:57:45 PM »
Gary,
I think what TTalma is looking for is the Home Switches position (machine reference) to be X -3 and Y -1.
This would mean his fence corner will always be Machine x0 y0 when the tool is moved there. 
Chad Byrd
Re: Can someone please explain how to use Home offsets
« Reply #4 on: August 02, 2018, 03:32:08 PM »
Yes currently it is homing fine. But the X on my machine is actually wider than the table. so the position where the X homing switch is located in not above the cutting surface. So once I do "Ref all Axis home", I have to enter X=-3, Y=-1 then hit go to 0.

I am doing it this way as I have some parts that need to be manually rotated 90 degrees, then 180, so I always want the part and tool referenced off the same point. this way holes line up as they should etc.
Re: Can someone please explain how to use Home offsets
« Reply #5 on: August 02, 2018, 07:35:32 PM »
Byrd,
I got what he wanted. I was only suggesting that it doesn’t get applied until you tell Mach to move to home and then it will move to X -3 as the home position.

Offline Mauri

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Re: Can someone please explain how to use Home offsets
« Reply #6 on: August 02, 2018, 08:01:56 PM »
Hi,
You could do it in Screen Load Script.
The first one is not Ref all Home part of Mach4 screen set  and the Second one is you add another button below the first and resize the first so it fits and call the function like the Ref all Home but with the following.
Then you can make the offsets like you need for your machine needs.
Regards,
Mauri.


In New Button

RefAllHomeWithOffset()
-- Homing Offset
offset_applied ="false";

In Screen Load Script.
---------------------------------------------------------------
-- Ref All Home() function.
---------------------------------------------------------------
function RefAllHome()
   mc.mcAxisDerefAll(inst);  --Just to turn off all ref leds
   mc.mcAxisHomeAll(inst);
   coroutine.yield() --yield coroutine so we can do the following after motion stops
   ----See ref all home button and plc script for coroutine.create and coroutine.resume
   wx.wxMessageBox('Referencing is complete')

end
---------------------------------------------------------------
-- Ref All Home With Offset() function.
---------------------------------------------------------------
function RefAllHomeWithOffset()
    mc.mcAxisDerefAll(inst)  --Just to turn off all ref leds
    mc.mcAxisHomeAll(inst)
    coroutine.yield() --yield coroutine so we can do the following after motion stops
    ----See ref all home button and plc script for coroutine.create and coroutine.resume
    mc.mcCntlGcodeExecute(inst, "G1 X0.1 Y0.1 F30")
   --mc.mcCntlGcodeExecute(inst, "G1 X0.1 Y0.1 Z0.1 F30")
   coroutine.yield()
    wx.wxMessageBox('Referencing and Offset Completed')
end
Re: Can someone please explain how to use Home offsets
« Reply #7 on: August 02, 2018, 09:54:51 PM »
Mauri,
I was thinking along those lines, making a script for it, but then thought....  This should be a feature (and it probably is)  but it may be buggy.   But I like your solution, very neat and to the point! Nice!  =)
Chad Byrd