I am currently using a NI 6210 connected to the R and Phi outputs of a SRS 830 lock-in amplifier. 
However, a stupid doubt settled in my head: am I setting the system properly? Why is it stupid? It has to do with the referential used to define "input" or "output".
What do I mean with that? I am using the NI DAQ to measure the LIA output signal (R and Phi). So, for me, the signal that goes into the NI is an INPUT, as I am providing the NI with a signal that it will process, so it should go to a AI channel. But the doubt is - well, it´s a system that is there to read an output, so perhaps it is only correct to send it to an output channel (so "output" matches "output"). My thoughts keep telling me that I am wrong, and I should just see the DAQ as any other instrument and accept that the "output" of the LIA is just "input" for the DAQ. Is it correct?
