How to set up an analog edge trigger to start multiple channel acquisition

[Babidi]

Hello there,

I'm trying to set up an analog edge trigger... with very poor results so far. The DAQ i'm using, NI USB 6008, doesn't support hardware analog triggering, so i have to build a VI to do that. I'm logging 6 MEMS accelerometer (voltage signal), for my application i would need to start acquiring data when the first of the six accelerometers (the closest to the source of excitation (impact)) gives a signal over a certain threshold (edge). It might seem a fairly easy to implement, but i'm a beginner with LAbView and it is driving me crazy! please help!

find attached a copy of my VI.

[John_P1]

Hi Babidi,

You might instead try starting with this example:

Continuous Acquisition with a Software Analog Start Trigger

It's a bit more complicated than using the blue Express VIs, but it should work out of the box for a single channel.  It sounds like you know which sensor is going to be high first so this should be suitable; if not you could always modify the code to check for all 6 channels.

You'll need to add logging yourself since this example only plots the waveform on the front panel.

Best Regards,