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Thread: how to wire galvo driver signal to ILDA with only X gnd and Y?

  1. #1
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    Default how to wire galvo driver signal to ILDA with only X gnd and Y?

    i have a small 10K scanner set from china which has a signal connector with 3 pins
    the 3 pins are X, GND, Y
    the signal required that manufacturer told is "Max 10V input singal"

    now i have my ilda connector which has X+ (pin 1) X- (pin 14) Y+ (pin 2) Y- (pin 15) and GND (pin 25)

    how would i wire this correctly? i use a pangolin FB3-QS. isnt this outputting +5v to -5v?

  2. #2
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    Default

    Use X+ Y+ and GND.

  3. #3
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    would'nt this give only half angle when using it with a FB3-QS as it only outputs 5v?

  4. #4
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    Quote Originally Posted by laserjohnn View Post
    would'nt this give only half angle when using it with a FB3-QS as it only outputs 5v?
    Yes. But, you have to work with what you have. I'd contact Pangolin AND your galvo manufacturer to see what they recommend in that case.

  5. #5
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    Your only other alternative would be to build a differential receiver front-end for that set of scanners. All you need is two op amps and some resistors. (You already have a +/- power supply for the scanners which can also power the op amps. Suggest using something like a TL-082.) This would give you back the full signal deflection.

    Note that your statement about the FB3 "only putting out 5 volts" is misleading: it outputs +/- 5 volts, just like every other controller that follows the ILDA spec. The ILDA spec for X and Y signalling is +/- 5V *differential*, which means if X+ is at +5V and X- is at -5V, that yields a +10 net signal. Now reverse those numbers, and you get a -10V net signal. The total swing between them is 20 volts, even though the voltage on any one pin (X+ or X-) never goes above +5 volts or below -5 volts.

    The issue is that the manufacturer of that cheap chinese galvo set did not add a simple $0.20 chip to handle the differential-to-single-ended conversion on the input stage of the amp. So your choices are to add the op amps yourself, or live with half the max scan angle by only using X+, Y+, and GND.

    Adam

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