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# Thread: DDCS V3.1 pulses to mm HELP!

1. ## DDCS V3.1 pulses to mm HELP!

Trying to setup the correct movements in the DDCS V3.1 Offline controller and I've gotten myself so lost and confused at this point and I could really use some help!

All 3 drivers are set to 4000 pulses

My X axis is a rack and pinion setup that's got a reduction of 3.2:1

My Y and Z axis are both on 1610 Ballscrews.

I tried searching for a calculator online of some sort to try and figure all of this out but haven't found anything that makes sense.

2. ## Re: DDCS V3.1 pulses to mm HELP!

Originally Posted by Dgee
Trying to setup the correct movements in the DDCS V3.1 Offline controller and I've gotten myself so lost and confused at this point and I could really use some help!

All 3 drivers are set to 4000 pulses

My X axis is a rack and pinion setup that's got a reduction of 3.2:1

My Y and Z axis are both on 1610 Ballscrews.

I tried searching for a calculator online of some sort to try and figure all of this out but haven't found anything that makes sense.
Link To Calibrator: https://weitling.info/calibrator/#!/S... Select Milling hope this helps

3. ## Re: DDCS V3.1 pulses to mm HELP!

What is the diameter of your pinion?
The following is from AvidCNC, and is based on their 1" (2.54 cm) pinion:

"MACH Settings for R&P:
The R&P system is based on a pinion with a 1" pitch circle. The total linear distance traveled per revolution of the pinion is thus 3.14159". With the 3.2:1 reduction, this means that the distance traveled per motor revolution is 3.14159 / 3.2, or 0.9817". If you have a stepper with 200 steps per revolution, this means you have 200 / 0.9817" = 203.718 steps per inch, or 0.004908" per step. With 10x micro-stepping , you would have 2037.18 steps per inch, or 0.0004908" per step."

You would just need to convert inch to mm.

For the Y and Z, I believe it is 4000 pulses/steps per revolution, with the ball screw pitch of 10 mm, that would be 4000/10 = 400 pulses per mm. This would give a theoretical resolution of 0.0025mm per pulse/step, which from what I understand matches the limits of the typical stepper motor (+/- 0.0025mm/step).