Calculate "Steps Per" In Motor Tuning

'Afternoon everyone,

Looking for some help on motor tuning in Mach3. To provide some basic background, I am running a PMDX-122 breakout board, a Gecko G320 servo drive, and an IMService servo assembly on a Taig 2019CR.
http://www.cadcamcadcam.com/index.as...PROD&ProdID=62

Now, under "Setup", it reads:

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The precise pulley ratio is slightly larger than 2.8:1. Use 5647.0588 steps per rev in quadrature mode (4X), and 1411.7647 in slot mode (1X).

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I assume I am in quadrature mode, so I have 5647.0588 steps per rev. Now, on the Taig, they use 20 TPI leadscrews. If I multiply 20 TPI by the above mentioned steps per rev, I get 112941.176 steps per inch. Is that what should be entered in the Motor Tuning page in Mach3?

Yes, that sounds correct.

Okay, great- That value sounded a big high so I wasn't sure. But thank you for the confirmation :D

Scott Nichols from MAch, give me the best solution:
In the settings tab (in the dro) on top of the reset tab, is the "axis calibration Steps per unit" You only have to input the movement you want measure hou much did it move , tell to MAch and set it. One minute , no calculating... !
Luis

Awesome, I'll give that a shot, too. Thanks! Although, I think the method we've done is a bit more scientific and (perhaps) more accurate.

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Originally Posted by Burn

Although, I think the method we've done is a bit more scientific and (perhaps) more accurate.

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It's more likely less accurate, because it doesn't account for error in the leadscrew and other components. Doing the math gets you in the ballpark, but you need to take actual measurements to get real accuracy. :)

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Originally Posted by ger21

It's more likely less accurate, because it doesn't account for error in the leadscrew and other components. Doing the math gets you in the ballpark, but you need to take actual measurements to get real accuracy. :)

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Aah- Now that I think about it, that makes sense. Any way you could walk me through how to do that method (measuring)? Seems like it's the absolute best way to go from what I've re-read now :)

I used a laser level (cross lines) and drew a line perfectly centered and ask mach to move 150mm , then Mach asked how much did it move. it was about 147.6mm, press ok and Mach asked " do you want Mach to set it?"
After I checked for a 1800mm length part cut and it was exactly..!

Luis