Using a DO output to trigger an AI task without extra cables?

[JKSH]

Hello,

I have a PXI-6229 (Multifunction DAQ) and a PXI-6723 (AO, with some DIO lines). My channel mappings aren't set in stone yet, so I can use either module.

For a test system, I'm using producing 2 continuous, periodic digital waveforms in the background (through 2 DO channels). The 2 waveforms have different patterns, but they are synchronized by being bound to the same task (Digital 1D Wfm, NChan NSamp).

Pattern A: 0 0 1 0 1 0 1 0

Pattern B: 1 0 0 0 0 0 0 0

For one of the test steps, I need read a finite voltage waveform (through an AI channel). When I arrive at this step, I'd like to start reading at one of the rising edges of Pattern B. How can I accomplish this?

One method I can think of is:

• Duplicate Pattern B on another DO channel
• Wire it back to a PFI line on my controller
• Use the PFI input to trigger the AI task. 

Is there a way to do this without an extra cable? Thanks in advance!

[CoffeeBreak · Accepted solution]

 Hi JKSH,

First I would like to say that your proposed method is a completely logical method and it will work. However, this method includes more physical routing so the trigger may be delayed.

You can use the DAQmx Export Signal (VI) to route your DIO line (with pattern B) to another output terminal such as a trigger. Then you can use this newly routed signal to trigger your AI channel. Here is the documentation for this specific VI:

http://zone.ni.com/reference/en-XX/help/370469AA-01/lvdaqmx/mxexportsignal/

[JKSH]

Thank you, Sam! That's exactly what I need.

[CoffeeBreak]

Of course! Glad to help and good luck with the rest of your application