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Author Topic: Problem with step motors
IvanMag
Newbie
Posts: 5
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Post Problem with step motors
on: March 8, 2012, 20:17
Quote

Hi, Sandy.
I have some problem with my motors.
Look to picture and you will see step-missing in it. What do you think, is it problem of motors\motorshield or what?
I use stepmotors with 0.9, but not from astrosyn.
photo:
Image
sandy
Administrator
Posts: 1317
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sandy
Post Re: Problem with step motors
on: March 8, 2012, 23:57
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Hi, actually I've seen this before on my machine - it's where at the end of each pixel, it drops back a couple of steps, and then jumps forward again at the start of the next one... Can't remember off the top of my head what I did to fix it though. I don't think it was a hardware issue though, it kind of, fixed itself with whatever I was also working on at the time. I'll have a think and see if anything comes up - I guess you have the most recent versions of the firmware and the controller?

Does it do this regardless of what your row size is?

Really nice sharp line quality though!

Sandy Noble
kongorilla
Pro
Posts: 362
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kongorilla
Post Re: Problem with step motors
on: March 9, 2012, 01:20
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This has happened on my machine, too, occasionally. My guess was that it happens with particular row sizes, because when I worked on a series of drawings with the same settings it happened on all of the drawings. Then when I started on different drawings (with different settings) it was gone. Perhaps it's the row size/pen width combination?
sandy
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sandy
Post Re: Problem with step motors
on: March 9, 2012, 07:52
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Right, well that does make sense actually, the first step in drawing a pixel is to move to the start point and that's calculated by doing position - (rowsize/2), so if rowsize is odd there's a good chance of some rounding issues. Not sure why it would be such a large error though - I would expect a maximum error of one step.

Might look a bit more closely at this on the weekend.

Sn.
kongorilla
Pro
Posts: 362
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kongorilla
Post Re: Problem with step motors
on: March 9, 2012, 08:17
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I just remembered that back in the "old days", when the controller made you select row sizes by increments of five, I always avoided sizes ending in five after seeing this happen a few times. I never really tested the theory, so I considered it one step away from superstition, but maybe there was something to it.
sandy
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sandy
Post Re: Problem with step motors
on: March 9, 2012, 12:16
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Right, I tend to stick to even numbers too so I'll attack it with odd numbers and see what comes out. IvanMag - can you tell us what rowsize (gridsize) and pen tip size you're using for that drawing?

sn
IvanMag
Newbie
Posts: 5
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Post Re: Problem with step motors
on: March 9, 2012, 14:20
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Ok, thnx! You are right, I used not even numbers in pen and grid size (0.35\45). Now, when this sizes are even, quality is more better!
About pen: I use it with Rotring isograph 0.35, 0.5, 0.7...mm
http://www.rotring.com/en/produkte/technisches_zeichnen/isograph.php
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