Elapse time after event

[colorofclouds]

Hi,I am collecting data with a DAQ. When the signal on one line falls from 1 to 0 volts (I identify this with a boolean value in my vi that changes from false to true) I want to change the way the signal on another line is processed and saved for the next 400 ms. So I am trying to find a way to keep this "true" value for 400 ms. Without some timer or delay, this value reverts to false very rapidly. Additional constraints: I am using labview 4 on macintosh.

Cheers
Yannick Huot

[Filipe A.]

Hello;

The only way to do that accurately is by using one of the general purpose counters (you didn't mention what board you are using, by I'm assuming you have a counter available in it).

You can program the counter to do retriggerable pulse generation, configure the pulse to have a width of 400m sec, and wire the digital line that is triggering the start of the 400m sec pulse, to the counter's gate input.

That will make the counter to generate a pulse of 400m sec, at every event of a trigger pulse.

Hope this helps.
Filipe A.
Applications Engineer
National Instruments