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About DLP Lightcrafter 3000 triggering a camera

Di Jin99
Prodigy 85 points

I want to use the DLP 3000 to trigger a Photron camera FASTCAM-APX RS. I followed the manual to set the device up. I used the static stored images mode. I used the Pin 3 and 4 of J7 for triggering. When I used an Oscilloscope to measure the output trigger signal, I found the signal is TTL but  the amplitude of the signal is very small, around 50 mV, which is useless. I don't know what is wrong. Could the problem be from the connector? And should I make some changes to the circuit? Thank you!

  • 0
    TI__Mastermind 30600 points
    Welcome to the DLP Forums and thank you for your question.

    The signal should be full scale - 0 to 3.3V, sorry that you're not seeing that. A couple questions:
    1. I infer that you can connect to the GUI. Do you have any problems with pattern sequence mode?
    2. Have you enabled the output trigger? In the upper right corner of the GUI there is a check box that says "enable"

    Take a look at section 2.6 of the user's guide for more detail: www.ti.com/.../dlpu006e.pdf

    Thanks,
    Paul
  • 0 in reply to Paul Goedeke
    Prodigy 85 points
    Hi, thank you for replying!
    I can definitely connect to the GUI and there is no problem with the sequence. Also I have enabled the output trigger or I cannot see the TTL signal even though the magnitude is not right. I think I have set the parameters of the GUI right since whenever I altered the pulse width and trigger period, the TTL signal I got would change correspondingly. Still I am wondering why the voltage is so low. Could you provide more suggestions? Thanks!
  • 0 in reply to Di Jin99
    TI__Mastermind 30600 points

    Hi Di,

    Can you follow this app note: http://www.ti.com/lit/wp/dlpa032/dlpa032.pdf

    Try populating R295 on the board. That should connect the external trigger to the correct VCC and fix your amplitude problem. Before plugging it into the camera, but sure to probe the voltage to confirm it is correct. If it is not, please let me know and we can keep trying to debug.

    Thanks,

    Paul

  • 0 in reply to Paul Goedeke
    Prodigy 85 points

    In the DMD I have, the  R295 is already removed so welding spot in the position of R295 is disconnected. For the document you suggested, I originally followed it and connected the pin 1 and 3 to my oscilloscope but I could get no TLL signal. Then I followed the manual of DLP 3000 where it said that pin 4 is the ground and pin 3 is the trigger output, then I connected the pin 3 and 4 to the oscilloscope and at this time I could get TTL signal although the amplitude is not right. Do you think it is necessary to use 0 resistor to connect the welding spots of R295 to solve this problem? Also could I call you to discuss about the problem so that it would be faster? Thanks!

  • 0 in reply to Di Jin99
    TI__Mastermind 30600 points

    The document suggests that you attach the 0 ohm resistor. Please do solder in R295. It should solve the problem.

  • 0 in reply to Paul Goedeke
    Prodigy 85 points

    Thanks for your advice. It helped solve my problem!