Event triggering TTL signal

I have written a program in flash for a decision-making paradigm to be used in psychological research. I am now needing to have a TTL digital signal output to an external psychophysiology recording device in response to specific events (e.g., button press, or presentation of specific images, etc.). I have seen a couple posts related to this question, but with no solution offered. Has anyone done something like this before - and if so, can you tell me how??

What is the nature of the device producing the TTL trigger signal?  Is it possible, for example, that it could produce a 1-microsecond pulse (that might not be visible on your plot of the signal) that would trigger the counter?  Are you really producing a digital pulse (i.e. is your circuit something that is either "on" or "off", as opposed to "produces an analog voltage in the range 0 to 5 volts")?  Are there other devices around that could be producing pulses that are being "picked up" by your counter?  Is the cable connecting the TTL pulses to the counter shielded?  Is the shield grounded at only one end?
These questions (and the previous one) suggest that the problem may be "electronics" rather than "LabVIEW" ...

Similar Messages

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    Hello,
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    Hello, and thank you for your reply.
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  • TTL signal vs TCP-IP, parctical and timing considerations

    We have just purchased a BioPac MP1 50 physiological recording system (www.biopac.com). We would like to start/stop an acquisition from another computer system and/or to add annotations and markers.
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    1) I would like to know first if anyone could recommend an easy solution to generate TTL signal (0 � 5V logical pulse) on both Windows and LINUX PC?
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    2) What are the latencies in read and writing/issuing TTL signals com? How does it compare with a dedicated byte stream through TCP-IP, on a dedicated cable and on a network cable?
    3) Are they any VI application that you c
    ould share to show how LabView 7.0 can talk through the respective ports to generate a pulse forming the trigger information being written or read in?
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    Donat-Pierre LUIGI

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    there is no control over this.
    Good luck,
    Chuck
    "Donat-Pierre" wrote in message
    news:[email protected]...
    We have just purchased a BioPac MP1 50 physiological recording system
    (www.biopac.com). We would like to start/stop an acquisition from
    another computer system and/or to add annotations and markers.
    To this end it seems there are two routes to consider. We could
    either use the built-in Trigger in/out capability with TTL signal of
    (0 and +5V square pulse) or use TCP-IP client-server to control it
    remotely (i.e. using VIs such as TCP-IP Listen). In the later case,
    I'd use the Beta LabView API libraries that BioPac is about to release
    for the MP150, instead of the dedicated AcqKnowledge 3.8.1 software,
    which is really good.
    Because we need to correlate event during the physiological recording
    of our experiment, it would be ideal if the resolution were of ms
    accuracy (i.e. latency less than 1ms) and we need to manage up to 16
    trigger channels.
    I have very little technical background knowledge on this. Thus, in
    order to help me evaluate a solution, I would appreciate any comments
    and suggestions.
    1) I would like to know first if anyone could recommend an easy
    solution to generate TTL signal (0 - 5V logical pulse) on both Windows
    and LINUX PC?
    For instance I read about using the 25-pin parallel port, but I am
    curious to learn about other possible alternative such as USB, USB2
    with or without adapter but also a very cheap card (a couple $100
    max). I am already ruling out serial connection, because I am told it
    is very slow and has horrendous latency.
    2) What are the latencies in read and writing/issuing TTL signals
    com? How does it compare with a dedicated byte stream through TCP-IP,
    on a dedicated cable and on a network cable?
    3) Are they any VI application that you could share to show how
    LabView 7.0 can talk through the respective ports to generate a pulse
    forming the trigger information being written or read in?
    I look forward to hearing your feedback and suggestions. Many thanks
    in advance.
    Donat-Pierre LUIGI

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  • TTL signal count problem: mistaken counting

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    Thanks a lot,
    KX
    Solved!
    Go to Solution.
    Attachments:
    pb_ttl1.jpg ‏80 KB
    pb_ttl2.jpg ‏223 KB

    What is the nature of the device producing the TTL trigger signal?  Is it possible, for example, that it could produce a 1-microsecond pulse (that might not be visible on your plot of the signal) that would trigger the counter?  Are you really producing a digital pulse (i.e. is your circuit something that is either "on" or "off", as opposed to "produces an analog voltage in the range 0 to 5 volts")?  Are there other devices around that could be producing pulses that are being "picked up" by your counter?  Is the cable connecting the TTL pulses to the counter shielded?  Is the shield grounded at only one end?
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    Message was edited by: 41457173
    Message was edited by: 41457173

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  • Event triggering by abap class & ISR

    hi gurus
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  • How to send a ttl signal with a good exactitude less than 10ms?

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    MD Electronic, France
    http://www.mdelectronic.fr
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    regards,
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