Procedures to calculate steps per inch

[DrStein99]

Ok finally got my machine setup right w/ motor pinouts, drivers, etc... Now the next step I have to figure out the steps per inch.

On a mach-3 system, there was a wizard I ran that moved the axis "xxx" number of steps. I hookup a dial-indicator, and measured the distance. I put the distance into the dialog box, and the program calculated the math and saved the value.

Is there a function I can do on EMC that does the same thing? If not; how / what way do I go about calibrating the machine ? I'm sure there's got to be procedures somewhere in the 135 page documents, which is starting to give me headache reading by now - sorry if I'm being lazy and just going here to ask, if that bothers anyone.

-Erich Stein

[eskimobob]

Sorry, new to this myself so don't know the definite answer however look at INPUT_SCALE in the INI file section of the integrators PDF.

I just set my machine up on the weekend and was going to have to do the same as you but when I put my dial gauge on the machine, it just happens to be already set correctly - yay!

Good luck.

[cyclestart]

Stepconf can do the calculation but you can also do this manually, I'll assume you had a reason for not using stepconf.

Originally Posted by eskimobob Sorry, new to this myself so don't know the definite answer however look at INPUT_SCALE in the INI file section of the integrators PDF.

Yes. In my user manual the formula is in section 5.3.7.3
Edit the INPUT_SCALE line for that axis in whatever .ini file you are selecting at emc startup. Restart emc (to reload the .ini file) to test your edits. Not as handy as Mach but not hard either.

For example my x axis is 8X microstepping for
1600 (micro)steps/rev * 5 rev/inch = 8000 (micro)steps/inch = SCALE

This is handy if you need to do pitch conversion
http://www.newmantools.com/tech/pitchconversions.htm

[DrStein99]

The pully ratio and leadscrew pitch on all three axis are a bit of a mystery. I could dismantle the machine, measure and check them, of course.

The Mach-3 function skips over all that, and simply moves the axis --- say, 2000 steps. I measure the distance moved w/ the dial - and thats the measurement. So if in 2000 steps it moves exactly 1/2 inch, I know its 4000 steps per inch.

-Erich Stein

[cyclestart]

I'm not very familiar with stepconf but believe it will allow you to test each axis before commiting to the settings ? This would take a bit of trial and error unfortunately.

The Mach feature you described might be a good feature request for emc.

[Big John T]

Originally Posted by DrStein99 The pully ratio and leadscrew pitch on all three axis are a bit of a mystery. I could dismantle the machine, measure and check them, of course. The Mach-3 function skips over all that, and simply moves the axis --- say, 2000 steps. I measure the distance moved w/ the dial - and thats the measurement. So if in 2000 steps it moves exactly 1/2 inch, I know its 4000 steps per inch. -Erich Stein

So skip over all that and just do a G1 move of 1 inch and measure that. If you move exactly 1/2 inch divide your steps in half...

John