Hi, I have an SR830 lock-in amp but instead of the standard GPIB or RS232, I would like to get the signal via BNC cable through an NI 9234 box. I was able to get some numbers with the DAQ Assistant, but I don't think it is getting the same data as the front panel has shown. Are there some settings that I am missing? Thank you in advance for helping!
I suggest you look at the manual, it is well documented; what I am saying here is only what I recall and my not be entirely correct.
I assume you are using the outputs from the channels to digitize. These outputs are ±10V and were meant to drive a strip chart recorder. 10 V represents full scale for your measurement, that is, if the the sensitivity is set to 1V and you get 10V out you have a 1V signal. So in order to get the same value as the display you need to keep track of the sensitivity scale and scale your values.
Lastly, I am not sure of the update rate for this output, I think is kind of slow, ie, no more than 512Sa/s, it may depend on the time constant . So what I am trying to say, adjust your digitizing rate accordingly.