How to implement trigger pulse

[pfl_436]

Hello,

I have run into a probably very simple but at least for me "tricky" issue:

The VI that I have attached below shows two tasks. The first one (left side) is to acquire US data from an external pulser/receiver. The second task is simply the logging of a thermocouple.

Until now I was using the trigger in the external pulser/receiver as a reference. What I want to implement is now that when the US task is started, my DAQ (PCI 6255) card will send s trigger signal to the external pulser/receiver to initiate the release of an ultrasonic pulse.

I was able to build/modify a couple of example VI's to release a 5V signal. But when I put them together with the existing US Vi, it doesn't work.

How would I add the output of an external trigger signal to the Ultrasound task (the one on the left side) below, and which changes do I have to make to the timing?

According to the manual of the pulser/receiver the trigger signal has to fullfil the following criteria: +5V, >100 ns wide into 50 ohms

Best,

PFL

[GerdW]

Hi pfl,

to start problem solving you should

- not create and kill tasks in each iteration of your loop. Init/DeInit is done only once outside the loop!

- don't rely on timed while loop to determine your timing. When using DAQmx devices you should rely on their onboard clock to maintain a sample rate!

[pfl_436]

Thank You for the reply. I once more looked at the examples and white papers that NI provides and actually found a working example for what I am looking for.

I'll take the comments you made and will try to work over my design again. It does work....but it does require a bit of work^^

Thank You,

PFL