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Coordinates are wrong
« on: July 24, 2009, 10:14:02 AM »
Hi everyone,

I saw a previous post asking about Mach3 sowing "massively wrong" coordinates but there were no replies that adequately answered the question. I have built a 60" x 48" x 9" CNC router, got through the first two tutorials, set units to inches, entered in all the motor tuning information according to the correct motor-leadscrew ratio (1000 SPI, 126 IPM, 90 accel). When I jog the router I get coordinates appx 6x the amount actually traveled. Please let this newbie know what he's doing wrong.

Much appreciated

Offline Hood

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Re: Coordinates are wrong
« Reply #1 on: July 24, 2009, 10:26:33 AM »
What is the pitch of the screws? Do you have any gearing between motors and screws? What type of drives or what is the microstepping of them.
Hood

vmax549

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Re: Coordinates are wrong
« Reply #2 on: July 24, 2009, 10:28:15 AM »
You r math for the SPI is off by 6x. List your setup and we can help do the math.

(;-) TP
Re: Coordinates are wrong
« Reply #3 on: July 24, 2009, 10:31:09 AM »
Screws are:

3/8-10, 2 start for Y and Z axes
1/2-10, 2 start for X axis

They are all driven by Xylotex 425 oz.in. steppers at 200 SPR with no gearing, they're all 1:1 pulley-belts.

Thanks

Offline Hood

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Re: Coordinates are wrong
« Reply #4 on: July 24, 2009, 10:38:43 AM »
Do xylotex have microstepping?
Hood
Re: Coordinates are wrong
« Reply #5 on: July 24, 2009, 10:46:07 AM »
Do xylotex have microstepping?
Hood

Yes - 1X, 2X, 4X or 8X, jumper selectable.  If he's really getting the DROs to show 6X the actual travel, I'd guess he has Mach moving in mm, and the Xylotex set for 4X microstepping.  That would give him almost exactly 6X.

Regards,
Ray L.
Regards,
Ray L.
Re: Coordinates are wrong
« Reply #6 on: July 24, 2009, 10:49:18 AM »
I haven't set it to any microstepping. I will check with Xylotex on that. As far as setting it to mm, I have set the default units to inches nearly a dozen times now.

Thanks

Offline ger21

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Re: Coordinates are wrong
« Reply #7 on: July 24, 2009, 11:26:07 AM »
It's 1/8 by default, so 1600 steps/rev, x 5 turns per inch. Should be 8000 steps/inch.
Gerry

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