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Author Topic: Mach4 cnc program min/max values  (Read 583 times)

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Offline Bob49

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Mach4 cnc program min/max values
« on: April 13, 2019, 03:33:06 PM »
Back when I used Mach3, I used to check the travels in my programs for obvious travel issues with the min/max values mach showed.  It was helpful as most of my programs run once only so there's always a bit of anxiety when pushing the go button.

When I moved to Mach4 a few years back I tried using the feature there, but never could get my brain around something in the x, y, z displays.  Yesterday I decided to give it another try.  Think I've sorted out the values are all in machine coordinates and for X and Y, the math computes to reflect my programs.  Z however is way out of range.  This morning I took another look and seen that if the Z values were correct in the min/max dro's my mill head would travel below the table by a rather large amount.  An example, the last program I checked in the min/max readouts should have showed me a combined z travel of right at 3.9".  Instead it reflected a total z travel of over 10".  I reloaded a few programs I've already made parts with and I see the same thing.  The programs didn't do what the z min/max values say.

If it just reads the program and reflects the values from that, there is a problem I'm not understanding.  Is it possible it takes tool changes into account?  That's not helpful to me in evaluating a program if that's the case.  I can't get the math to work out though if that's the case, and I don't know why the Z tool change position in my M06 macro would be included in those travel values.  Anyone use that feature and have an understanding of it?

Regards
Bob
Re: Mach4 cnc program min/max values
« Reply #1 on: April 13, 2019, 03:46:42 PM »
Hi,
the program extents can be seen on the Toolpath tab. They can be displayed in either machine coordinates OR work
coordinates. There is a button to select which.

Check also the Machine Diagnostics tab that the g92, Work Shift, and Head Shift offsets are all, zero.

Craig
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Offline Bob49

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Re: Mach4 cnc program min/max values
« Reply #2 on: April 13, 2019, 04:15:44 PM »
Hi Craig,

Thanks for the quick response.

Your pic of the Toolpath tab is exactly where I'm viewing the min/max values as well as the current position in the top dro's.  Toggling the machine coordinates on and off only changes the values in the current position x, y and z dro's there.  The dro's in the min and max don't change with that toggling.  The values in the current x, y and z dro's show the correct position of the head and table with the machine homed to the home/limit switches.  And reflect correctly the position in G54 work offset.

In checking the values you mentioned on the diagnostics tab, they are all zero's in those 3 offsets you mentioned.  I've never gotten any of the min/max values to toggle between machine coordinates and my work offset.  Even so, doing the math on x and y shows the current program travels, just not so with Z ever.  It's always wrong.

Regards
Bob
Re: Mach4 cnc program min/max values
« Reply #3 on: April 13, 2019, 04:30:51 PM »
Toggling the machine coordinates on and off only changes the values in the current position x, y and z dro's there.  The dro's in the min and max don't change with that toggling.   
Regards
Bob

FYI ... same here,
Russ
Re: Mach4 cnc program min/max values
« Reply #4 on: April 13, 2019, 04:38:21 PM »
I don't know how I did it, but now the extents DO show in Machine coords. ? ? ? ? :o
And I cant get it to go back to Program coords.
Standing by ........... curiously interested.
Thanks
Re: Mach4 cnc program min/max values
« Reply #5 on: April 13, 2019, 04:43:25 PM »
Hi,
I've just been experimenting and I find that Current Positions changes between machine coords an work coords
but the Max and Min extents remain in machine coordinates.

Within that limitation (Max and Min in machine coords) all axes (x, Y ,Z) display correctly.

Craig
My wife left with my best friend...
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Offline Bob49

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Re: Mach4 cnc program min/max values
« Reply #6 on: April 13, 2019, 04:53:03 PM »
What would prevent Z from displaying correctly in my use with X and Y displaying correctly?  Those values clearly are incorrect in my version of Mach.  Wonder if there's a way to get min and max to display in the current offset (G54, etc).  It would be a bit easier to confirm the program travels are correct and not have some outlier that might cause a problem.  I can deal with all in machine coordinates if that's all that can be had there.

I'm using a licensed version of build 3233 if that has any bearing things. 

Thanks
Bob
Re: Mach4 cnc program min/max values
« Reply #7 on: April 13, 2019, 04:57:07 PM »
Hi,
I opened the screen editor to have a look at how the Max and Min DROs are fed. I have attached a pic of the
properties of the Max_X DRO. Note that it is fed directly from a register. There does not appear to be any code
to switch back and forth between the register (machine coordinate) and work coordinates. It would appear to me
therefore that the Max and Min extents can only be displayed as machine coordinate values.

If you wish to have Max and Min work coordinate values it would be simple enough to make another six DRO's
and populate them with the corresponding register value  minus the current axis offset, is the work coordinate.

Alternatively you could change the existing DRO's to be driven by a script that does the same thing.

Craig
« Last Edit: April 13, 2019, 05:13:15 PM by joeaverage »
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Re: Mach4 cnc program min/max values
« Reply #8 on: April 13, 2019, 05:00:35 PM »
Hi,
on my installation the Max and Min of all three axes is reading correctly albeit in machine coordinates only.

I can't think of a reason that the Z axis alone would be out of whack excepting a corrupt copy of Mach.
I'm using build 4095 currently.

See my previous post for an idea or two to display a work coordinate Min/Max.

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach4 cnc program min/max values
« Reply #9 on: April 13, 2019, 05:02:59 PM »
Hi,
sorry, my reply #7 should have an attachment.....have since edited it to include it.

Craig
My wife left with my best friend...
     and I miss him!