Announcement

Collapse
No announcement yet.

Pulse generator for stepper motor

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Pulse generator for stepper motor

    Howdy. I am looking for a confirmed working simple stepper pulser / speed control module that I can wire up to a driver. I bought one of the grey digital readout units on eBay and it was dismal . The other style (2 buttons + knob) would be fine but a post in another forum said they are bugged and only work in one direction. The import units are all copies of each other and I can't tell if any one seller has a fixed version. I wish eBay had item reviews like Amazon!

    I already have steppers on each axis and I want to have bi-directional powered lead screws for manual machining.

    Thanks,

    Ed
    Last edited by daGrouch; 06-15-2015, 06:24 AM.
    _________________________

    Eddie "Thread Killer" daGrouch (YouTube channel)
    Smithy CB-1220 (Clark CL500M)

    Sometimes ya gotta re-invent the wheel to learn how to make wheels.

  • #2
    What you could use is a standard Step/dir drive and use a directly connected PWG or hand wheel, which is essentially a 100p/rev encoder.
    They come up on ebay quite frequently, the advantage is they have the tactile graduated indents.
    Max.

    Comment


    • #3
      I have those running through Mach3 and they are great for rapids with my 2mm pith screws but I find turning those smoothly for a good finish just as hard as turning the hand wheels smoothly.

      The lathe has the typical 1 speed screw engagement for Z in one direction and I don't have change gears for it. I want to mimic that electrically in both directions on both axis' (axi?) so I am not running back and forth to the MDI.

      In my mind I would have a speed control and 2 switches (On/OFF and Direction) for each axis for simple turning and facing. A multi-pole switch for flipping between CNC and pulsers would be added at the input of the drivers.

      I am finding that I spend more time sitting at the computer playing with wizards or CAD'ing when I could have made 3 simple parts manually. Besides, my machine is not accurate enough to use CNC all the way so I have to stop and tweak too much.

      Ed
      Last edited by daGrouch; 06-15-2015, 09:19 AM. Reason: formatting
      _________________________

      Eddie "Thread Killer" daGrouch (YouTube channel)
      Smithy CB-1220 (Clark CL500M)

      Sometimes ya gotta re-invent the wheel to learn how to make wheels.

      Comment


      • #4
        You could just run an encoder though one of these chips, it outputs step/dir from the encoder input. Put a nice weighted handle on the encoder and something to give it a bit of drag to make it smooth.

        http://www.usdigital.com/products/in...s/ics/LFLS7184

        Comment


        • #5
          Originally posted by daGrouch View Post
          I am finding that I spend more time sitting at the computer playing with wizards or CAD'ing when I could have made 3 simple parts manually.
          True that Ed. You left off CAM'ing, post-processing and multiple screams of "Why the *&@$*# did it do that!"
          Milton

          "Accuracy is the sum total of your compensating mistakes."

          "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

          Comment


          • #6
            Originally posted by DICKEYBIRD View Post
            True that Ed. You left off CAM'ing, post-processing and multiple screams of "Why the *&@$*# did it do that!"
            Just enter code though MDI for simple stuff, I can send commands pretty quickly like that and it beats manual crank turning. Or just set the feed and use the arrow keys.

            Comment


            • #7
              Originally posted by macona View Post
              Just enter code though MDI for simple stuff, I can send commands pretty quickly like that and it beats manual crank turning. Or just set the feed and use the arrow keys.
              Yup, I do a lot of simple stuff that way and it works great. No rocket surgery needed. The head bashing comes when I have to do the little model airplane venturis with an internal elliptical curve and/or taper from both sides of the part that have to meet each other in the middle. Bore ID of .177" with a .160" carbide boring bar. Lotsa places for a tiny lapse in concentration to cause a crash. Not that that ever happened of course.

              However, it is a miraculous thing to watch when it runs right and well worth the time spent....I think.
              Milton

              "Accuracy is the sum total of your compensating mistakes."

              "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

              Comment


              • #8
                All that is needed to operate most stepper drivers is two signals, one for direction and the other is a stream of pulses that provide one step per pulse. There are many ways of doing this, both mechanical (switches) and electronic.

                The most modern way would be with a PIC device like PICAXE or Arduino or Basic Stamp. These can be programed to provide those signals. Controls could be switches, thumbwheel switches, a pot, or a variety of other things.

                Another electronic approach would be a pulse generating circuit using a timer chip like the 555 and a pot for speed control. A switch for directional control and perhaps a switch with a single pulse circuit for jogging.

                Both of these approaches are dead simple and there is no reason why they should not operate properly and reliably.

                Another approach would be a rotary encoder with a tachometer output. This would provide the pulses and a switch would be for the direction.
                Paul A.
                SE Texas

                And if you look REAL close at an analog signal,
                You will find that it has discrete steps.

                Comment

                Working...
                X