Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: ChrisT2637 on May 07, 2011, 07:02:21 PM
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Digital read out problem
I’m running a home built CNC router. It is a typical stepper motor set up. I use Mach3 controls program and VCarve CAM program. Everything was working just fine. All of my out puts are right, motor tuning and steps are correct. When I design engrave a project with Vcarve everything comes out to scale. In other words everything works except one thing. The digital readout for my XYZ axis is incorrect. When my machine moves one inch the DRO shows it moving 25 inches. If I send the machine back to zero the machine goes right back to its original position. The only thing I can see that is wrong is the DRO is out of scale.
I don’t remember making any changes, maybe I did. The DRO just seem to be out of scale for no good reason. Is there a way to set the DRO back to the right scale? Any and all help would be much appreciated.
Thanks Chris
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Set the counts per unit on Config menu then Ports and Pins then Encoder/MPG page, sounds like you need to multiply the values there by 25.
Hood
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thanks for your help. I multiplied the values by 25 it works right up until I loaded a g code file from V carve. now its back to doing the same thing. I think some how the file created in v carve is changing the settings.
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Sounds strange, almost like you have your native units set to mm and have tuned your mtors so that 1 unit instead of moving 1mm actually moves 1 inch.
If you attach your xml I will take a look, would also be handy if you let me know if you have microstepping drives and if so what the amount is and if you have gearing between motor and screw, lastly the pitch of your screws.
Hood
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thanks again, I'm using keling step motors and drivers. set at 1/8th microsteping using a 4 start 8 thread per inch drive nut. with 32 steps per minutes. My native units are set to inces "first thing i checked". Sorry but I'm just back yard inventor i am unfamiliar with the xml. file. 200x8x2=3200
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3200
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The xml is the file that holds your config, it has the name of the profile you use and is located in the main Mach3 folder. So for example if you open Mach look at lower right you will see the profile name, look in the Mach3 folder for a file with that name and an xml extension. You will likely nneed to copy it to your desktop then rename to something like Chris.xml and then use the additional options on the reply page to attach it. Would also be good if you attached the G Code file as well.
Hood
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thanks again
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once again
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The xml attached seems fine for your motors etc but it doesnt have any encoders set up?
Hood
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Might be missing your point here, but "blackhawks" uses G21 and therefore is in mm so I'd expect your DROs to be scaled up by a factor of 25.4. If you want Vcarve to output in inches just select it on the job setup page.
Ian
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I don't want to sound dumb, I might have this next part totally wrong. My machine is built with hybrid step motors. Wouldn't the encoder issue come in to play if i were using servo drives?
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I think we really need to clarify what you are meaning by Digital Read Out. I was presuming you had glass scales on your machine which you were monitoring via Mach however it seems that may not be the case.
If you are meaning that the X Y Z Dro in Mach for the axis position are showing more than you expect then it would seem like Ian has mentioned the difference between G20 (Imperial) and your code being G21(Metric). If you want to see the DROs stay with your setup units (Imperial in your case) then choose the option at the top of the General Config page which will lock them to native units.
Hood
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Thanks again for everyone help. It was my DRO for my xyz axis I was referring to. It turns out the problem was just a dumb mistake on my part. Some how I had changed the post processor setting in my Vcarve program from mach3 inch to mach3 mm. I'm still scratching my head on how that happened. The computer is dedicated to this machine and has been set up and running correctly for a long time. I cant think of any reason I would have changed the set up. I would ever have solved this issue with out your help.
Chris
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All part of the learning curve, it gets easier as time goes on but the learning never stops :)
Hood