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  • CheapAss_dro now online and working.

    I got the visual basic exe program posted on my website for download. (later on today) It runs in XP, 98Se windows.

    It works by reading pins 10,11 as X quadrature encoder phase inputs. 12,13 as Y encoder inputs. I am using a opto22 board to isolate my port from the clarostat ($50 ea.) optical rotary encoders. I have hooked them directly to the port pins.

    A onscreen status block changes color from green to red as the diameter gets below screen target setpoint. It also fires pin 2 for x, pin 3 for y when it transitions to target setpoint.

    This is to mount a output light fired by the pins local to the lathe to give a heads up.

    Encoders will be cable operated on wall next to lathe. Cable distance has to be less than 15' to computer/encoders or voltage drop exists and lost counts may happen.

    The processor must be fast enough to run a 5ms loop to ensure no lost counts. Test computer is a 1.6 gig intel, Laptop @ 1.4 I don't have anything older here.

    ------------------
    David Cofer, Of:
    Tunnel Hill, North Georgia

  • #2

    Well done, Ibew. You continue to amaze.

    How are you mechanically connecting the encoders to the X and Y? Can you possibly post a pic of that? This is cool, I may just try it.

    -M
    The curse of having precise measuring tools is being able to actually see how imperfect everything is.

    Comment


    • #3
      Ibew, those Optop22 boards cost 50$ each?
      Nice progress on the DRO.

      Comment


      • #4
        no, the opto boards cost me .50 each. I bought a dozen or more.

        Same board I sent you. Fast modules thou. You'd be better off rigging a pic or other interface.

        Or just connecting them straight in. I have done that use a biasing resistor and hook the encoder output right to the parallel port.
        (old computer)

        Hooking the motorcycle cables up to a cross slide? you just put two tabs on it, one to hold the cable housing, other the anchor the cable to the moving slide. Other end wraps around a disc, I used weights last time to pull on disc to keep tension on cables. You could use a spring like I did the press.

        I'll take a picture, I'm still down and in the house sick.

        David

        Comment


        • #5
          This SOB is sick and does more for this board than all of us put together.If I only understood half of what he says I could make the stuff also.

          No offence meant, David

          ------------------
          The tame Wolf !

          Comment


          • #6
            What IOWOLF said.
            The curse of having precise measuring tools is being able to actually see how imperfect everything is.

            Comment


            • #7
              I have to chime in also. You impress me.

              Comment


              • #8
                Ok, now I feel comfortable admiting that I ussually have no clue what David is saying.

                As previously stated, can you take pictures of the hook up to the lathe so we can see how the x and the y are measured?

                Damn nice work. A mind is a great thing to use!

                Comment


                • #9
                  Mmmm.... getting somewhere, I see.

                  BTW - once relieved of it's winbloat, those machines should be capable of a sampling rate in excess of 100Khz... a low end Pentium should be able to manage the task under DOS with acceptable results...

                  IBEW - I believe I've mentioned this before, but I'll repeat it, just in case - check out TurboPascal 7 for DOS - for doing this kind of stuff, it's really nice, cuz' you can get complete control over the machine - and it's a free download.

                  Comment


                  • #10
                    So where can I find your web site?

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                    • #11
                      <font face="Verdana, Arial" size="2">Originally posted by nt1953:
                      So where can I find your web site?</font>
                      Click on his profile, the link is in there.

                      I will also admit that I usually have no idea what Ibew is talking about, but it is still interesting to read.

                      Comment


                      • #12
                        There is a free DOS DRO program.

                        http://www.lindsayengraving.com/othe...rests/dro.html
                        Free software for calculating bolt circles and similar: Click Here

                        Comment


                        • #13
                          Sorry guys, I was wanting to put one more sub into it before posting it. One that you can configure the parallel port, *(blocks on the right, and pulses per inch) and it loads "your" unique setup each time. I ain't doing so well, I fell out on the couch like a lazy sick bastich..

                          Yeah, you can hook the encoder directly to the parallel port. No parts needed. I am trying to figure out what kind of biasing resistor you need. It works great without anything thou. Possibly since it is a optical encoder limiting the current. But for protection against stray noise it might need some resistors.

                          I promised to try to explain it how even IOWOlf can use this and hook it up.

                          You got 4 wares on pins coming from the lil blue rotating thing that looks like a speedpot, It has a turny shaft thing on it, you hook that to the cable with a lil round discy. put a spring on it to keep it pulled up tight..
                          Now them thar wares, one is a 5volt hot, one is a 5 volt negative, you need 5 volts on them in the right wares. Them other two? they are pulse wares that make the computer know where that there shaft is. If you turn the shaft on that lil blue thingy, it makes them wares pulsate and throb quite consistiently (*you know how your big toe throbs when you hit a bedpost barefoot? ) actually 128 times each in a full turn. Now them throbbing things on them wares happen opposite and the same time to each other. This way it's called quadrature. Now them throbs, have the following logic and what just happened a throb before tells the computer which direction it's going..

                          example encoder..
                          throbbing pulses.. (1=throb, 0=no throb)
                          00,01,11,10 to right=cw, left = ccw
                          if you follow that pulse train from that rotating blue thingy *encoder to the right and look at what jus happened the pulse change befo, it tells you cw direction on that lil shaft on that encoder thingy. Now if you follow that pattern to the
                          other direction it's backards to the first pattern or ccw. If your computer is really smart, meaning somebody told it (a program) how to watch that encoder and see what it did last? it'll know and remember.

                          *yeah I'm being sarcastic. I love you guys.. this is not hard once you get the picture on how the encoder really works....

                          For you "other guys" with the pocket full of pencils and slide rulers.. here.. this is the vb subroutine. Note: the lil throbbing thing is pulsed on with the "1" and off with the "0".. He he..

                          '^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^
                          '00,01,11,10 to right=cw, left = ccw
                          '****************** Conditional statements, get the bits of encoder************
                          'x_anew=present status of the encoder
                          'x_aold= last status of the encoder..


                          X_Anew = Right$(PortCIn.Caption, 2)

                          If X_Anew = X_Aold Then Exit Sub
                          'ifn it ain't changed, it don't matter none.

                          Text1.Text = X_Anew & X_Aold
                          'diagnostic screen block of input

                          If X_Anew = "00" And X_Aold = "10" Then 'CW
                          X_pos = X_pos + X_incr
                          X_Aold = X_Anew
                          Exit Sub
                          End If

                          If X_Anew = "01" And X_Aold = "00" Then 'cw
                          X_pos = X_pos + X_incr
                          X_Aold = X_Anew
                          Exit Sub
                          End If

                          If X_Anew = "11" And X_Aold = "01" Then 'cw
                          X_pos = X_pos + X_incr
                          X_Aold = X_Anew
                          Exit Sub
                          End If

                          If X_Anew = "10" And X_Aold = "11" Then 'cw
                          X_pos = X_pos + X_incr
                          X_Aold = X_Anew
                          Exit Sub
                          End If


                          If X_Anew = "00" And X_Aold = "01" Then 'ccw
                          X_pos = X_pos - X_incr
                          X_Aold = X_Anew
                          Exit Sub
                          End If

                          If X_Anew = "01" And X_Aold = "11" Then 'ccw
                          X_pos = X_pos - X_incr
                          X_Aold = X_Anew
                          Exit Sub
                          End If

                          If X_Anew = "11" And X_Aold = "10" Then 'ccw
                          X_pos = X_pos - X_incr
                          X_Aold = X_Anew
                          Exit Sub
                          End If
                          If X_Anew = "10" And X_Aold = "00" Then 'ccw
                          X_pos = X_pos - X_incr
                          X_Aold = X_Anew
                          Exit Sub
                          End If

                          End Sub


                          Next? somebody buy me a palm pilot so I can program it and do away with the computer and post that program next..
                          (hint? the lil "runx" button is a axis feed) Not a cnc, but a feed to target.. Yeah, it'll probably get some lil motors next.. you know things that don't throb.. *(he he).. Since it is turning "on" a pin.. it must want to turn on a feed motor.. Eager computer? A lathe don't need a whole lotta program.

                          [This message has been edited by ibewgypsie (edited 09-07-2005).]

                          Comment


                          • #14
                            Evan:
                            I'll get around to porting it into turbo basic, a compiled exe dos program. On pins and all..

                            faster, better, quicker in dos. A cheapAss computer will be a excellent dro-feed control.
                            It won't be so fancy, no big blocks and buttons.

                            David

                            0hh yeah, most DRO linear encoders work the exact same way as this rotary, they just cost hundreds of dollars. Most are glass with lil blocks etched on them. them chinese slide ones?, well they "serial talk" to the computer but are expensive as well. I can talk to them as well.

                            [This message has been edited by ibewgypsie (edited 09-07-2005).]

                            Comment


                            • #15
                              Wirecutter:

                              yeah, look up my cnc press project, I used a rotary encoder, Wrapped a xl toothed belt around a gear, cut the belt hooked one end of the belt to a spring, hooked the other end to the "slide" on the press and AWAY I went counting off. Used two rollers to keep it wrapped around the lil gear.

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