Trigger Analog Output on Analog Input Level

[mattb1]

Is it possible to trigger an analog output on the level of an analog input using a cDAQ chassis with an AI and an AO card?

I found a similar thread, but the OP is using a PXIe 6358 that has AI and AO on the same card.

https://forums.ni.com/t5/LabVIEW/Analog-Start-Trigger-does-not-work-for-Analog-Output-tasks/m-p/3234...

[tolltroll]

Hi Matt,

What hardware are you using? Which cDAQ, AI, and AO modules? How exactly do you want to synchronize these signals, and to what?

In order to check out an example for a good starting point in LabVIEW, you can go to Help->Find Examples->Hardware Input and Output->DAQmx->Synchronization.

N. Boni

Applications Engineer

[mattb1]

I am using a cDAQ 9178 and have attempted this with an NI 9221 AI card and an NI 9263 AO card.

I would like to read a single AI channel and when it reaches a certain level, write a single AO channel. It seems the shipped examples show how to synchronize multiple AI channels, but not an AO to an AI.

[tolltroll]

Hi Matt,

The process for synchronizing AIs to AOs is essentially the same, you'll just want to change the "Read" to a "Write" with whatever data you want to send out. 

Check out this tutorial on triggering, specifically section 4D on analog triggering:

"Tips and Techniques in Data Acquisition Triggering - NI-DAQmx"

http://www.ni.com/tutorial/4329/en/

-N. Boni

Applications Engineer

[mattb1]

I had looked at that example before, but receive an error from the Start Trigger VI that has something to do with an analog edge start trigger not being supported by my hardware.

I am now wondering if this is at all possible with any C-series AO modules. I have looked through several datasheets for them, but haven't found a definite answer.

[tolltroll]

Hi Matt,

My mistake, you may be right -- I found this KnowledgeBase article on the topic:

"NI CompactDAQ (cDAQ) Support for Analog Triggering"

http://digital.ni.com/public.nsf/allkb/851828B06A20E01B862571DA0005591A

That said, it will help to get an idea of what task it is you're trying to accomplish (you want to trigger AI and AO but why? To what end?) 

N. Boni

Applications Engineer