Internal routing DIO

[TeamPicatinny]

I'm using the NI USB-6216 data acquisition device. I want to measure a frequency on an analog input channel. That part is easy. The signal is not always present so I want to start acquisition (trigger) when the first pulse arrives. I can do this using a "software trigger" but would like to simply use a reference trigger. I understand I need to use a digital pin for that. Is there a way to route the AI channel to a digital pin internally and then designate it as the reference trigger?

[andres.vargas]

I suggest using a PFI terminal as a Timing Input Signal, you will find information about this on the User Manual for the 6216, in Chapter 7.

Best, 

Andrés

[TeamPicatinny]

Thanks Andres.  As I understand it, using a PFI would require me to wire my signal to both an AI and a PFI. The cables are already designed so rather than add wires, I'd use a software trigger method. I was hoping for some internal routing of an AI so that when it switches from DC to a pulse signal, I can then measure the frequency and be done. My measured signal is DC until a wheel moves. Then it pulses at the speed it's turning. To verify it works, I arm the DAQ and then instruct the user to spin the wheel. I trigger on the first pulse, then acquire sample data.

[andres.vargas · Accepted solution]

The reason I suggest a PFI terminal is that they are often also an AI. This sounds to me like what you are looking for. You should look at the product information and see if there is a PFI linked to one of your AIs. Then if you use that AI for data input and then the linked PFI terminal with your trigger, you will be set.