Anybody a whiz with Excel spreadsheets?

by Doc Nickel

Okay, here's the situation: In order to finish adjusting the travel of my CNC lathe, I need to slightly alter what's known as the "turns ratio" of my stepper drives. It basically compensates for minor inaccuracies, so that when the computer commands the carriage to move 1.0000", it moves purty durn near to 1.0000" as possible, given the limitations of my particular setup.

It's an easy adjustment in the software, but you first have to do a little math to figure out how to adjust it. In this case, one puts a dial indicator, or other precision measuring device, on the axis to be adjusted, and to tell the software to move that axis a fixed distance, like one inch.

And, if you come up with, say. 0.991" of actual movement, or 1.014" of actual movement, you adjust the "turns ratio" which compensates for that error.

One of the guys over on the Centroid board came up with an Excel spreadsheet, that does the calculation for you- just enter how much you told it to move, and how much it actually moved, and it gives you a compensation number to enter into the "Wizard" in the software.

The problem is, I can't open it. Others have had trouble with it too, so it's not just me. I don't have Excel on any of my computers, and would rather not have to buy a copy from Microsoft just do do this one quick task.

I tried a 'free' reader download, which could open it, but can't alter the document- it's read-only. So the calculation won't work.

OpenOffice was recommended to me, so I downloaded that, and IT says the fiel's corrupt, and can't read or open it.

If anyone would like to give it a whirl here's the link to the XLS file. What I'm wondering is if one of you could extract the actual formula out of the spreadsheet, and post it in more or less plain English, so I can just use a friggin' calculator on the damn thing. happy.gif


Posted on Dec 29, 2017, 8:07 PM

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  1. Found the problem.... J.Cook, Dec 29, 2017
    1. ... Okay.... Doc Nickel, Dec 29, 2017
      1. Turns per inch ratio. Mike, Dec 29, 2017
      2. formula. snark, Dec 29, 2017
  2. Shareable Link. Jelsemium, Dec 29, 2017
    1. Or you can just get Google Sheets for yourself. Jelsemium, Dec 29, 2017
      1. Google Sheets. Typeminer, Dec 30, 2017
  3. Thank you, ladies and gentlemen.... Doc Nickel, Dec 30, 2017


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