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I figured it out YIPPPPPPEEEEEEE :) New Kid On The Block — Parallax Forums

I figured it out YIPPPPPPEEEEEEE :) New Kid On The Block

idbruceidbruce Posts: 6,197
edited 2011-01-07 07:06 in Propeller 1
Hello All

Very soon you folks will have a new stepper driver to play with. We are not talking about a slow poke here, we are talking about a true blue stepper driver. This thing flys. For the last several days, I have been trying to get the steps to accurately to match the counter. Just a few minutes ago, I got them to sync. 1,000,000 steps at about 15 revs per second and it stopped right where it was supposed to. :)

This code is based upon a sample from MagIO2 with JonnyMac's assitance. Thanks guys. Wait till you see this!

Bruce

Comments

  • idbruceidbruce Posts: 6,197
    edited 2011-01-06 16:30
    Okay, I was wrong, it went several revs past. But I am very very close.

    Bruce
  • ElectricAyeElectricAye Posts: 4,561
    edited 2011-01-06 17:09
    I applaud all developments for Propeller-based stepper motion - I like using stepper motors.
    But beware that you are very likely pushing the electromechanical limits of your stepper motor - and stepper motors in general. Although you might get this to work for demonstration purposes, you might find that such high speeds are not very practical. I'm afraid your steppers will have little or no torque at these speeds and/or it is very likely to skip steps because of induction issues in its coils.
  • idbruceidbruce Posts: 6,197
    edited 2011-01-06 17:19
    ElectricAye

    I am very aware of all of that. The speed in this software is very easily reduced. Take a look at the speed torque curves I have attached for my motors. I am not way out of bounds at twenty revs, because I am just pushing small pieces of wire. Additionally, there is 50V going through my motor coils.

    Bruce
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2011-01-06 17:27
    ElectricAye,

    The driver he's using does microstepping. So there's more than one pulse per full step.

    -Phil
  • ElectricAyeElectricAye Posts: 4,561
    edited 2011-01-06 17:52
    idbruce wrote: »
    .... I am not way out of bounds at twenty revs, because I am just pushing small pieces of wire....

    Yeah, but I've seen your kind before. First it's just small pieces of wire you're pushing around. Then it's larger pieces of wire. Then it's two, three, sometimes four wires at a time. Then it's a piece of lamp cord you've got twirling in circles. And next thing we know: you're swinging 20 ton sewer pipe from the Golden Gate Bridge and bitching about why your system keeps skipping a step here and there. Well.... don't come crying back to me when that happens!
  • idbruceidbruce Posts: 6,197
    edited 2011-01-06 17:56
    ElectricAye

    LOL Okay, looks like I will have to find a different shoulder. I do appreciate the concern though, however, I have been studying this all for about three years, so I am far from ignorant about the subject.

    Bruce
  • ElectricAyeElectricAye Posts: 4,561
    edited 2011-01-06 18:05
    idbruce wrote: »
    ... I am far from ignorant about the subject....

    If I were you, I wouldn't state it that way. Understand: the ISI (International Scale of Ignorance) goes off to infinity in both directions.
  • idbruceidbruce Posts: 6,197
    edited 2011-01-06 18:08
    ElectricAye

    Ah yes, I always keep forgetting about the ole' ISI. I won't be able to go twenty revs with this machine anyhow, the ramping distances are too short. However, my other machine, Yiiipppppeee :)

    Bruce
  • idbruceidbruce Posts: 6,197
    edited 2011-01-06 18:10
    ElectricAye

    I bet when I am done with this driver that you will like it. :)

    Bruce
  • pgbpsupgbpsu Posts: 460
    edited 2011-01-06 18:13
    Bruce-

    I've followed your thread/exchanges with MagIO and JonnyMac with interest. I have to admit that I've never worked with a stepper motor (or even seen one as far as I know). So I don't think I have the proper appreciation for your accomplishment. Any chance of a video of these things (and your code) in motion? Regardless, congratulations. I hope you've picked up some programming off the tips provided by MagIO, JonnyMac, Terry Allen, Lawson, and Kuerenko, et al. I know I have.

    That burst code that showed up in that thread was brilliant. I don't have a use for it but it's got to be good for something!

    Congrats,
    pb
  • idbruceidbruce Posts: 6,197
    edited 2011-01-06 18:20
    pgbpsu

    Yeah, I will take pictures and make a video when it is up and running. This stepper code and other programming code is certainly slowing down the momentum I had going.

    The biggest thing that learned from all those guys is that they are some really smart dudes, and you can't forget Phil Pilgrim. He is another one of those very smart people. But yes, I am picking up the good tips.

    Thanks For Your Response
    Bruce
  • ElectricAyeElectricAye Posts: 4,561
    edited 2011-01-06 18:33
    idbruce wrote: »
    ElectricAye

    I bet when I am done with this driver that you will like it. :)

    Bruce

    I bet you're right. But for now I'm going to tell you it's impossible, impractical, imperious, impermeable and imperialistic. Negative psychology works on you 20-ton sewer pipe swingers every time.
  • idbruceidbruce Posts: 6,197
    edited 2011-01-06 18:35
    ElectricAye

    LOL You are a funny guy.

    Bruce
  • Cluso99Cluso99 Posts: 18,069
    edited 2011-01-06 23:39
    Bruce: Just a warning from those who know... Never say something is impossible with a prop or you may just end up eating a prop when someone does it. There was a discussion last year about the prop not being able to do USB High Speed and in a very short time Micah proved that statement wrong! There are lots of other things we thought impossible too.
  • Cluso99Cluso99 Posts: 18,069
    edited 2011-01-07 00:17
    My comment was not to say something is impossible because someone will prove you wrong. (No, Bruce didn't say anything was impossible).

    Bruce: What hardware are you using to drive your steppers? (maybe it was in another thread?)
    I have been looking at the Allegro A498x stepper driver ICs. Of course they are simple to drive but can only do 1-2A. However, they are fine for a RepRap.
  • idbruceidbruce Posts: 6,197
    edited 2011-01-07 07:06
    Ray

    Please refer to this thread for a deep ongoing discussion pertaining to stepper driving http://forums.parallax.com/showthread.php?128408-I-need-a-Spin-counter-expert-to-examine-some-code-for-me-PLEASE-)

    You may also want to look at http://forums.parallax.com/showthread.php?126523-Microstepping-a-motor-with-the-Propeller-and-PWM started by ElectricAye.

    If you are are looking at IC chips instead of buying a commercial driver, I would suggest the L6208 from STMicroelectronics. They will give you (3) free samples of this IC as well as others. Order (3) samples of each of these: L297, L298, L6203, L6208. With these chips you will have a wide array of choices.

    I was going to create my own driver boards, but purchased G251's from Gecko Drive instead.
    http://www.geckodrive.com/

    Bruce
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