Trigger

[UARK]

Attached is a program I wrote to generate and acquire signals and write the acquired voltage values to a text file. I would like to use a trigger to start recording my acquired signal (and eventually, I would like to use the same trigger to write the generated signal, so that the generated and acquired signals are synchronized); however, as the program is now, every time I try to run a test, I continue to get an error message related to the analog trigger. Physically, I have a live wire hooked up to PFI 0/AI START TRIG (pin #11 on my E-Series SCB-68), but no return wire.

(1) Is the trigger in the right place in the program to do what I want?
(2) Do I need a return wire in addition to the live wire for the analog trigger?

Thanks for your time!

[RavensFan]

I think you need to establish the trigger before you start the tasks.

I think you want to start the analog input before you start the analog output.

There are numerous DAQmx examples that also include triggering the  Example Finder that should help you.

I don't know what you mean be "return wire".  Is it a virtual wire on the block diagram, or a real world copper wire connecting to your DAQ device.

[UARK]

Thanks for the advice. I have done some work modifying my code (attached). I have it set up with an optional trigger, though I don't know if I actually need it. In answer to your question: I meant real-world copper wires. I have a live wire running to port PFI 0 on my connector block,  but no "return wire" or D GND wire connected. Is this the correct configuration to use the digital trigger? Also, my program starts recording (writing to text) when I run the program, but is there a way I can easily pad my signal on the front end, so that I can see the first deflections in my generated and received voltage signals? I had one idea, which was to write pre-trigger samples, but I'm pretty sure in order to do that, I would need to actually use the digital trigger. Is there a way of doing this wihout a trigger?