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Author Topic: Z-Axis Dro - Odd behaviour?  (Read 2784 times)

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Offline Davek0974

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Z-Axis Dro - Odd behaviour?
« on: January 16, 2016, 10:30:48 AM »
Can someone have a look at the video clip I have linked below?

It shows my Mach3 plasma screen before a file load, during file load and then when pressing my "Set Origin" button.

As you will see, the Z is happily parked at 14.991mm which is where it really was after the end of the previous run. When i press set-origin it jumps to 0.437mm then to -0.9mm then to 0.437mm where it stays. The actual axis does not move - just  the DRO freaks out and leaves a meaningless reading on it which puts it in a bad position for a dry run on a new file.

The 14.991mm is wrong as well because my final Z move is always to 15mm dead, the difference  between 15mm and 14.991mm is the reading of the "THC Adjustments" DRO when the last cut finishes, if i run with THC off it always ends on 15mm dead.

Here is a link to a video showing what I believe to be odd behaviour of my Z-axis DRO.
https://youtu.be/WCmHRbIpm1o

Is there any logical reason for this, or a cure maybe???

The set-origin button does this...
DoOEMButton(1008)
Sleep(500)
DoOEMButton(1009)
Sleep(500)
DoOEMButton(242) 'Copy X Y Z to G54
Sleep(500)
DoOEMButton(160) 'Regen Path
   

« Last Edit: January 16, 2016, 10:35:51 AM by Davek0974 »
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline BR549

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Re: Z-Axis Dro - Odd behaviour?
« Reply #1 on: January 16, 2016, 10:52:56 AM »
Just so I do not have to do a search to figure it out is this a LPT ver or an ESS version ??

(;-) TP

Offline BR549

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Re: Z-Axis Dro - Odd behaviour?
« Reply #2 on: January 16, 2016, 11:11:46 AM »
Comment out the last 4 lines of the button code  They are not needed.  

IF yo insist on using it then add in another line at teh end

DoOemButton(1010)

Offline Davek0974

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Re: Z-Axis Dro - Odd behaviour?
« Reply #3 on: January 16, 2016, 11:11:57 AM »
I should have mentioned, this is a parallel port system with a CandCNC Mp3000-DTHC2 on it.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Z-Axis Dro - Odd behaviour?
« Reply #4 on: January 16, 2016, 11:40:53 AM »
Comment out the last 4 lines of the button code  They are not needed. 

IF yo insist on using it then add in another line at teh end

DoOemButton(1010)



Hmm, will try that out tomorrow but I have found odd things happen if the tool path is not reflecting the actual setup - this needs the regen line adding back in.

No idea why this line is there anyway DoOEMButton(242) 'Copy X Y Z to G54 ??
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline BR549

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Re: Z-Axis Dro - Odd behaviour?
« Reply #5 on: January 16, 2016, 02:17:55 PM »
By simply resetting 0,0 you will NOT change any thing in the toolpath other than where 0,0 actually is.  It will NOT effect teh cutting nor even change teh toolpath unelss you are 9 miles off teh tool table in relation to teh toolpath.

Test it you will see (;-) You do not need to regen to make it all work correctly. When you regen you are recycling ALL of teh G28.1 in the file THAT is what effects teh Z values. Same if you try to do a Run from here. The Z will end up WAY OFF position.

Now if you MUST have it then you need to program around teh problem. At the beginning of the script record teh actual Z value and save it to a variable then after teh Regen routine runs reapply teh Saved Z vale BACK to the  Z DRO value. I do the same trick for teh Run From Here routine so I do not have to worry about remembering to reset teh Z value back to position before it runs. BUT that is another chapeter in teh CNC plasma cutting book Making teh Run from here work properly so that you can restart Plasma cutting. AND YES teh RFH in Ver .067 is different than other versions (;-) It looks like Art tried to fix it for Plasma cutting but did not quiet get it right.

(;-) TP

« Last Edit: January 16, 2016, 02:21:09 PM by BR549 »

Offline Davek0974

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Re: Z-Axis Dro - Odd behaviour?
« Reply #6 on: January 16, 2016, 02:35:21 PM »
Hi again ;)

My set-origin button was created by someone on this forum I think, many moons ago, i just asked for what i wanted and that was offered up :) It gets used a lot but was told it needed the regen in there, so there it stayed, it is a total PITA though as it can take some time to regen a big file.

I will play with this tomorrow and see how it plays without that feature and if needs be then storing the Z and replacing it is the way to go.

Sounds like you really could write a book there, ever thought of it :)

In theory, my Z DRO should never be off of 15.00mm between cuts, let's see if I can attain that goal.

This still does not explain the small offset related to the THC adjustments DRO but thats always a small amount - still very annoying though as the last line in the code is Z15.00 and it never gets there :(  Unless the tHC is off.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline BR549

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Re: Z-Axis Dro - Odd behaviour?
« Reply #7 on: January 16, 2016, 03:32:04 PM »
IF you want a quicky test  Load your cut file then where 0,0 would normally be  set hit zero axis X zero axis Y  the do a regen to set teh toolpath exactly .

NOW simply move over to a new Origin Hit ZeroX then ZeroY  then look at teh toolpath it is basically the same with just teh cross hairs moved over to the new 0,0  . It will be that way UNLESS you make a move that is WAY off teh table size then it will show the far off offset.

I spent YEARS working with Mach3 plasma making all kinds of time saving gizmos for the shop here. They cut 5 dys a week 8 hrs a day most of teh time.  This like autorestart of a torch cutout. auto indexing right , auto indexing up , Preveiw cutting, G68 rotation to fit teh part to the material,etc,etc.  I was using teh Sword and T word long before it was popular to do so (;-). When CandCNC came along here I heaviely redid a lot of the functions like I used his Cut table and Mach3 tool# to autosetup cut files based on the tool#.

But like I said that is another story. I tried to get the Website to setup a specific plasma cutting section but that never happened so a lot of things over the years just all got blended into the mainstream Mach3 stuff. ANd  A lot never made it here. I have stacks of notebooks somewhere on teh plasma CNC process and Mach3.

(;-) TP



Offline Davek0974

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Re: Z-Axis Dro - Odd behaviour?
« Reply #8 on: January 16, 2016, 04:56:59 PM »
If we ever meet, i'd buy you a pint, but bring your notebooks ;) ;)

I will be trying this out tomorrow, I was just always led to believe that the toolpath display actually had more relevance, it seems not.

Don't go anywhere, I may have several hundred more questions :)

And yes a plasma section would have been cool, it's not really the same as mills and lathes, needs a different touch.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline BR549

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Re: Z-Axis Dro - Odd behaviour?
« Reply #9 on: January 16, 2016, 09:42:25 PM »
YEP there is an ART to plasma cutting that most millers or routers do not understand. The real trick is to maintain Constant velocity for cutting. Slowing down for a corner does not make any sense for plasma cutting (;-)

THAT is another chapter in teh book(;-)

(;-) TP