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  1. #91
    Quote Originally Posted by chip View Post
    jonathan double check youve sent him the pm as ive some how ended up with it,your address etc..
    Sorry about that! I've sent it to the right person now

  2. #92
    ok jonathan the pm got to me :) ill get it off to you as soon as it turns up to mine and we can all look forward to you smoking the thing

    no pressure :lol:

  3. #93
    Excuse me,
    The PC parallel port outputs a binary signal, meaning it has two levels, off / on; or 0 / 1. The 0 is represented by a voltage less than 0.8v The 1 represented by a voltage greater than 2.4v.
    Because the signal of interest is a PWM waveform, the voltmeter will be showing the average of the highs & lows of the signal. PWM means Pulse Width Modulation. By varying the proportion of ON time to OFF time in a given interval (20ms) the resulting effect is an analogue voltage. If the ESC wants a true analogue voltage input, a small value capacitor (1μF) between signal pin and ground will help.
    If you have access to an oscilloscope this would all be really clear.
    Thank you class for being attentive. Now, run along and play with your nice machines!

    Oh! I just answered my own problem! Use the oscilloscope to monitor the output of the PWM line (from Mach3), and see how similar it is to the DCBLM drive module requirement!!
    Templecorran
    Where the Light was kept during the Dark Ages

  4. #94
    Oh! I just answered my own problem! Use the oscilloscope to monitor the output of the PWM line (from Mach3), and see how similar it is to the DCBLM drive module requirement!!
    errrr.... let us know if you make any sense of the problem or if you use the capacitor, im asuming you already have an ESC and servo tester ?

  5. #95
    Quote Originally Posted by templecorran View Post
    ...signal of interest is a PWM waveform, the voltmeter will be showing the average of the highs & lows of the signal...If the ESC wants a true analogue voltage input, a small value capacitor (1μF) between signal pin and ground will help
    The ESCs we're using require a PMW signal with 20ms period. The range of the duty cycle used by the ESC is only roughly 5% to 10% - which means you don't get a very high resolution with mach3 connecting it directly. Only a handful of speeds in fact. Still probably sufficient in reality, but not ideal - hence why I'm still interested in investigating the servo tester adaptation. I agree a capacitor will certainly be required here, since the PWM signal is being fed into an ADC.

    Just out of interest I connected my model car transmitter up to the parallel port yesterday in a similar fashion - it works fine which implies the servo tester conversion should also. I'm trying to control the parallel port in C now, so I can get the car driving itself around...

  6. #96
    there are two things im dreading on this build....
    hole sawing 25mm for the Y screw and drilling and tapping the bed plate

    up to now iv used my diy spindle to do all my drilling and i was gagging to to be able to say id done the whole build with it and a tiny cowells 90 lathe:dance: however.... i think i may need to stop f***ing around and borrow a heafty drill

    there is probably loads more stuff i should be flapping about but at this point i cant see past the drilling and tapping..... more drilling and tapping.... and!!!..... b***cks!!

    Click image for larger version. 

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    for now i decided not to support the floating bearing on the Z screw, the housing that came with it seem such a waste of valuable space... ill make a low profile one if i have trouble with it whipping around

  7. #97
    Servo tester arrived :)
    I dismantled it straight away and sadly the PCB is different. I guess it's not surprising, hobbyking.com are allways changing their inventory.
    We will still be able to do the same modification to both of them though - the voltages are similar.

    I'll let you know as soon as I've done it - got a fair bit of work to do at the moment :(

  8. #98
    dont be rushing it, i dont think either of us are in dire need of mach spindle control at the mo

    have a crack at it in your own time jonathan, dont feel any pressure from me... im at least slack hand full of skinned knuckles away from fitting steppers never mind anything else

    good luck when you do get to it :)

  9. #99
    Ok then, it's just you sent it special delivery so I thought you were in a hurry!

    'im at least slack hand full of skinned knuckles away'
    You do think up some good expressions!

    I'm going home for the weekend and I intend to get my router to the point of cutting stuff. I intended that last time I went home, but as is always the case with these things they take longer than expected and I ran out of metal.

    Anyway, where did you get the long 1/8" cutter from for your little brushless motor? I'm warming to that idea for making PCBs...could use a really high feedrate with the cutter going at 60krpm (or more..) with one of the in-runner motors I've got.

    Can't you get the existing spindle to drill nice grid of holes in the bed plate when it's all set up? That's what I'm intending to do.

  10. #100
    i got one from germany (ebay) "Gravierstichel 3,175x115mm 60x0,32mm VHM f. Pantograph"

    then i found some cheeper ones in france (ebay) "1 fraise graver(long taille) 3,175*600,25mm V-type"

    iv been looking into sharpening them whilst still in the motor... it would need a jig making.... should get some good use out of them if they can be sharpend without to much hassle

    the worry for me are the bearings on the nose, im convinced they will need cooling unless you splash out on ceramic ones and at those prices id still want to cool them, at 48000rpm they were very hot in under a minute, it might stay cool if you use one bearing but i think the runout will suffer, it needs some research

    the other spindles are fine, i managed to hole-saw 25mm for my Y screw with the large one... had to take my time though, it keept tripping out my power supply

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