Calculate steps

Discussion of Mach3 CNC control software
kjetilhansen
Posts: 46
Joined: Tue Nov 05, 2013 10:55 am

Calculate steps

Post by kjetilhansen » Mon Feb 23, 2015 9:48 pm

Hello :)

I am using Gecko g540 with mach3 to run my shapeoko, but have not calbrated it yet. I understood that the G540 had 10 microsteps so when i enter 50 in the motor tuning and asks it to move 20mm it stops at about 16,xxx.. Is there something I am missing?

cvoinescu
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Re: Calculate steps

Post by cvoinescu » Mon Feb 23, 2015 10:25 pm

What's that 50 supposed to mean?
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

Damin69
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Re: Calculate steps

Post by Damin69 » Tue Feb 24, 2015 5:11 am

Go get the Manual from http://www.machsupport.com/help-learnin ... t-manuals/
On Page 76 it tells you how to calculate the steps for Mach3. You can also use the Built in tool within Mach3 You tell it how far to move in which ever direction. Then you measure how far it actually moved tell Mach and it calculates for you.
Shapeoko 2 #6971
Upgrades
Makita 0701, Nema23s, ACME Z Axis, Nema 23 Belt drive
Expanded to 1000 x 1800
Electronics upgrade C-10 BOB, SainSmart ST-M5045 drivers, Mach3
Damin69's Build Log

kjetilhansen
Posts: 46
Joined: Tue Nov 05, 2013 10:55 am

Re: Calculate steps

Post by kjetilhansen » Tue Feb 24, 2015 5:59 am

Hello,

cvoinescu;
In the shapeoko wiki it tells me that GRBL is 8 microsteps, and adds up to 40 steps/mm, and I Googled that G540 uses 10 microsteps so I changed the 8 to a 10 and calculated again and it gave me 50 steps/mm This value I punched into Mach3. I used the auto calibratin and that gave me somthing around 57 in that value, but that was not 100% accurate...

Damin69:
Thank you, will read and see if I can find what I am missing here... I used the auto calibration tool, but I could not get it that accurate and I belive it is better to just calculate this to get it better :)

lioramsalem
Posts: 88
Joined: Mon Jun 09, 2014 1:43 pm

Re: Calculate steps

Post by lioramsalem » Tue Feb 24, 2015 8:09 am

kjetilhansen wrote:Hello,

cvoinescu;
In the shapeoko wiki it tells me that GRBL is 8 microsteps, and adds up to 40 steps/mm, and I Googled that G540 uses 10 microsteps so I changed the 8 to a 10 and calculated again and it gave me 50 steps/mm This value I punched into Mach3. I used the auto calibratin and that gave me somthing around 57 in that value, but that was not 100% accurate...

Damin69:
Thank you, will read and see if I can find what I am missing here... I used the auto calibration tool, but I could not get it that accurate and I belive it is better to just calculate this to get it better :)
AFAIK, using the tool is much more accurate then calculating the number...
(for example, belt tension is different from one setup to another.)
I just used the tool with 150mm digital caliper. I can get an accuracy of <0.1mm while jogging and 0.2-0.3 mm on actual material cut which I find to be ok...

Just wondering, what accuracy you guys can get with Shapeoko2?

LA
ShapeOko 2 #5840 w/ NEMA23, ACME Z axe belt upgrade, limit switches, spindle speed control, 400w brushless spindle, 9mm belts, aluminum bed, eShapeoko X carriage and belts system

Build log: http://www.shapeoko.com/forum/viewtopic.php?f=5&t=3650

cvoinescu
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Re: Calculate steps

Post by cvoinescu » Tue Feb 24, 2015 2:00 pm

57 sounds about right if your pulleys are 18-tooth, not 20. Did you check that?
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

kjetilhansen
Posts: 46
Joined: Tue Nov 05, 2013 10:55 am

Re: Calculate steps

Post by kjetilhansen » Tue Feb 24, 2015 2:57 pm

Aah, no I did not. I checked the wiki and since I have a stock shapeoko 1 i made the stupid mistake to assume I had those pulleys...

Then will;
10 * 200 * 1/18 * 1/2 = 55,555 be right?

I am also getting wrong values at the Z axis, in the wiki it sais it supposed to be 320 steps/mm but with the 10micro steps this gives me a 1600 steps/mm and this is not quite right...

cvoinescu
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Re: Calculate steps

Post by cvoinescu » Tue Feb 24, 2015 3:25 pm

If you have a stock Shapeoko 1, the pulleys would be 18-tooth MXL -- that's 2.032 mm pitch (0.08"), not 2 mm.

Stock Shapeoko 1 and 2 have M8 threaded rod for the Z axis. That's 1.25 mm lead, so yes, a 200 step-per-rev motor with 10x microstepping gives 1600 microsteps per mm. Maybe you don't have the stock threaded rod?
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

kjetilhansen
Posts: 46
Joined: Tue Nov 05, 2013 10:55 am

Re: Calculate steps

Post by kjetilhansen » Tue Feb 24, 2015 3:38 pm

Then with shapeoko 1 with G540;

X and Y axis is 54,68066491688539
and Z axis (with m8 rod) is 1600

Just if anybody else need this information :)

Ill check the Z axis, it's probably right

Thank you :)

kjetilhansen
Posts: 46
Joined: Tue Nov 05, 2013 10:55 am

Re: Calculate steps

Post by kjetilhansen » Wed Feb 25, 2015 5:06 pm

I just can't seem to get this to work... With the 54,6806... when it is suppose to move 10mm it moves 9,5, I then use the auto calibrating tool, ask it to move 10mm, and I punch in that it moved 9,5. I then try again, and it is still off...
So I belive something I do or have is wrong...

I counted, I have a 18 tooth pulley, so I am guessing that XML is also right...
The steppers I have is sm42ht47-1684b
And I use the G540 (witch I have not changed anything on, so it should be 10 micro steps)

I may also add that when I used GRBL it was accuate..

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