How to send trigger to external devices using labview

[labview.edu]

Hello, I need help in sending a trigger to external device using labview.

I have mounted strain-gauges on the beam and using labview to continously recording the strain values. Now I want to send the trigger (ttl/make/break) to outside device as soon as strain values goes over certain limit. I am new not labview and mostly using express vi's. Also I can start the strain acquisition when strain value goes over certain mark. But I am not sure on how to send the trigger pulse to the external device using labview. I am attaching the pic of some of my efforts.

System Information: Labview 8.5.1, SC-2345 connector block, SCC-SG01 Strain module, PCI-6251 DAQ Card and SCC-DO01 Digital Output Module.

Thanks,

Sine

[mikeporter]

Unless I am confused by your description, a trigger is simply a digital output that you toggle when desired, so you would generate it the way you would any other digital output.

Mike...

[labview.edu]

I know what trigger is, i just don't know how to generate/send it. I started using labview this month only.

I want to generate/send the trigger out when strain value reaches certain threshold as mentioned earlier.

Thanks,

Sine

[mikeporter]

Ok, the best thing to do is go to the examples that ship with LV and look for examples of how to do discrete digital IO.

Mike...

[labview.edu]

Can you suggest any blocks that I can use?  or how to do it?  suggestions are welcome 🙂

THanks,

Sine

[doublejlifton]

Hi,

I am acquiring a sinusoidal analogue signal using a USB 6008. I need to generate a digital trigger when the amplitude of the sine wave is zero.

How might I go about doing this?

I am a mech eng student so programming is not my strong point.

Please find attached a plot of the signal I need to generate triggers from, please ignore the data point. The signal is noisy.

Kind regards,

Joe

[Michelle_N]

For this application, the 6008 is very limited. To do this you would need a device capable of analog triggering:

Can I Create a Digital Pulse Train That is Synchronized with My Analog Input Signal?

http://digital.ni.com/public.nsf/allkb/67CCAAF13C8617FC86256E01006C3D69?OpenDocument

The 6008 does not have analog triggering capabilities.

[doublejlifton]

Thank you for the reply, could you suggest a DAQ suitable for analogue triggering.

Cheers,

Joe Lifton

[Elizabeth_K.]

The best way to find the DAQ you need, is to go to ni.com/daq, and then use the links on the side to narrow down on exactly what you want.  I narrowed down a list that has voltage AI with analog triggering in the USB form factor, but you can narrow down another way if you wish.

Regards,

Elizabeth K.

National Instruments | Applications Engineer | www.ni.com/support