Rather than try to explain, I drew a little vi with comments that I think
will help you with your problem.
http://w3.one.net/~marksowa/newsgroup1.vi
Mark
"JNR" wrote in message
news:5065000000080000001A300000-1004225886000@exchange.ni.com...
> I have an application in which I do two things:
>
> 1. Monitor 8 data channels (all analog) and write the data to file at
> a sample rate of about 100Hz.
>
> 2. Play an AVI movie in a LabView ActiveX control for Microsoft Media
> Player.
>
> I wrote the VI, and it works fine, so far. The movie shows up in a
> window on the front panel, along with some graphs that display the
> data being collected from the 8 data channels (while it is
> simultaneously written to file).
>
> I need to add the following feature, and I am not sure of the best way
> to do it.
>
> CURRENTLY:
>
> Right now, when I run the VI, it asks me for a name for the data file
> (to which to write data collected by the VI), and also the name of the
> AVI movie file to play. It then loads the AVI movie file in Media
> Player. If I click the Play button in the Media Player window in the
> VI front panel, the movie begins playing.
>
> WHAT IS NEEDED:
>
> One of the 8 channels of data being collected is a trigger channel.
> The noise on this channel is about 0.2 volts. It receives trigger
> pulses periodically of around 4.5 volts (100 mS duration). I have code
> in place that checks to see if the voltage is over 3.0 volts (trigger
> ON) or below 3.0 volts (trigger OFF). The trigger is activated
> hundreds of times during the the 8-10 minute period the movie plays.
>
> I need to detect the FIRST trigger and use it to automatically start
> playing the movie. The requirements are:
>
> 1. The movie should begin to play with the first trigger ON state
> detected.
>
> 2. The movie should not be interrupted by further ON/OFF activity on
> the trigger channel.
>
> Can anyone offer a neat solution for that?
>
> I am relatively new at LabView, so please be as explicit as possible.
>
> Thank you.
