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Thread: Dave question about adjusting 15k scanner???

  1. #1

    Default Dave question about adjusting 15k scanner???

    Dave or anyone else, can you help??

    im looking at buying this DAC - http://www.die4laser.com/die4dac/index.htm

    this is the spec he gave me -

    The DAC internally has a 12 bit DAC but only the top 8 bits are used with the Mamba driver.
    There is a precision 4.096V ref on the board so the output does not drift with temperature (a requirement for hitting bounce mirrors)
    The output is differential or single ended, the +ve output going from -4V (0x00) to +4V(0xFF) and the -ve output doing the inverse.
    It requires a single +3.6 to +6.6V supply (nominally +5V - I grab mine from the USB port). It generates a stabilised +/- 5V on board to run the output stage.
    RGB output is TTL 1 bit per colour. There is also composite blanking.
    The down side is the Mamba software is 129 Euros http://www.medialas.de/secure/Januar...R_industry.pdf
    Speed is approx. 20k points doing RGB on a Pentium M 1.7GHz laptop.

    now i know the 15k scanners need 5v to fully operate.

    he also said they could be adjusted -

    I could mod the DAC for +/- 5V o/p but you risk slight clipping of the o/p waveform at full drive.
    Can you adjust the gain of your galvo amplifier?

    can i adjust the 15k scanners so this DAC will work with them???

    any help is welcome???
    Eat Sleep Lase Repeat


    Aluminium Optic Mounts

    http://www.laser-man.co.uk/opticmounts/

  2. #2
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    Default

    RTFM!!!



    You can adjust the scale for the X and Y axis. Just work out the scan angle you are getting with a full +/-5v swing, and then with your new dac, adjust the scale for each axis so achieve the same angle.

    And if you're not sure about anything, ask us for help before you blow anything up

    Don't forget to adjust the scale back to what it was if you use it with anotehr DAC.

    I'd suggest you just get the guy to make it work properly, as the ILDA standard specifies +/-5v at full swing, or just use a different DAC.
    Now proudly stocking and offering the best deals on laser-wave

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    http://stores.ebay.com.au/Lasershow-Parts

  3. #3
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    Default

    I think I'm right in saying that +5 and -5 would be full scale on the scanners making them move the maximum angle.
    therefore +/-4 will just be a smaller angle which will be fine.

    Jim

    Edit: Aidrian answered while I was typing.

  4. #4
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    Yeah... agreed. The scanners will still work fine Andy, just not as wide.

    I'd really suggest getting the problem fixed at hte DAC, not applying a bandaid solution to the scanners
    Now proudly stocking and offering the best deals on laser-wave

    www.lasershowparts.com
    http://stores.ebay.com.au/Lasershow-Parts

  5. #5

    Default

    Quote Originally Posted by aijii
    RTFM!!!



    You can adjust the scale for the X and Y axis. Just work out the scan angle you are getting with a full +/-5v swing, and then with your new dac, adjust the scale for each axis so achieve the same angle.

    And if you're not sure about anything, ask us for help before you blow anything up

    Don't forget to adjust the scale back to what it was if you use it with anotehr DAC.

    I'd suggest you just get the guy to make it work properly, as the ILDA standard specifies +/-5v at full swing, or just use a different DAC.
    LOL ive not heard that saying for a while.

    ok well im not sure about anything and im asking for help??

    im a real novice and know nothing, give me some tips. Im really struggling to get another DAC, this guy lives in wales and its a good price and hes very helpful.
    Eat Sleep Lase Repeat


    Aluminium Optic Mounts

    http://www.laser-man.co.uk/opticmounts/

  6. #6
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    Default

    How much is it Andy, I'm in the middle of building a couple of parallel port dacs but have been waiting for the DAC0832 chips for over a month now.

    Jim

  7. #7

    Default

    ok point taken, but he said he can adjust it to 5v, so all i need to do is adjust the scanners right??
    Eat Sleep Lase Repeat


    Aluminium Optic Mounts

    http://www.laser-man.co.uk/opticmounts/

  8. #8

    Default

    Quote Originally Posted by JimBo
    How much is it Andy, I'm in the middle of building a couple of parallel port dacs but have been waiting for the DAC0832 chips for over a month now.

    Jim
    same here, j-gee is having problems with them.

    Well i dont know how many he has left and i think he may be doing me one slightly cheaper. Ill ask him and let him know your interested
    Eat Sleep Lase Repeat


    Aluminium Optic Mounts

    http://www.laser-man.co.uk/opticmounts/

  9. #9
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    Default DAC0832

    I got my DAC0832 chips from National Semiconductor. I went to their website and signed up and they send me two chips as FREE samples. They even sent it express mail. Even shipping was free.

  10. #10
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    Default

    hi guys .... just want to clarify what Adrian said
    to prevent any confusion about the ILDA Standards ( even i get confused sometimes )

    and yes scanner manufacturers dont alway use the ILDA standards but you can always scale them just using a couple of resistors

    here they are below.....
    X Controls the horizontal beam position.
    This is a bipolar analogue signal whose voltage range is 10V peak-to-peak differential.
    A differential voltage level of -10V shall deflect the laser beam to the left side of the projection area. A differential voltage level of +10V shall deflect the signal to the right side.
    A differential voltage of +10V occurs if the normal signal line has a voltage level of +10V with respect to the voltage level of the inverted signal line. When compared to the ground level of the differential driver, the voltage level of the normal signal line shall be +5V and the voltage level of the inverted signal shall be -5V.

    Y Controls the vertical beam position.
    This is a bipolar analogue signal whose voltage range is 10V peak-to-peak differential.
    A differential voltage level of -10V shall deflect the laser beam to the bottom of the screen. A differential voltage level of +10V shall deflect the signal to the top of the screen. A differential voltage level of 0V shall place the beam in the center of the screen vertically.
    A differential voltage of +10V occurs if the normal signal line has a voltage level of +10V with respect to the voltage level of the inverted signal line. When compared to the ground level of the differential driver, the voltage level of the normal signal line shall be +5V and the voltage level of the inverted signal shall be -5V.

    R.G.B. Controls the Color intensity signals.
    This is a unipolar analogue signal whose voltage range is 5V peak-to-peak differential.
    A differential voltage level of 0V shall produce no color output. A differential voltage level of +5V shall produce maximum color output.
    A differential voltage of +5V occurs if the normal signal line has a voltage level of +5V with respect to the voltage level of the inverted signal line. When compared to the ground level of the differential driver, the voltage level of the normal signal line shall be +2.5V and the voltage level of the inverted signal shall be -2.5V.
    hope this helps


    all the best ... Karl

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