I have the BNC connector DAQ and am using the first 2 analog inputs to read in voltage from a device. If i graph 4 inputs for example, on Ai2 and Ai3 I still see the same signal as Ai1. Why is this ocurring and how do i prevent it? I would expect to just see noise coming from the 2 unattached bnc inputs but instead I see signal, is there that much cross coupling in this device? Or am i not gorunding it properly? I am connecting over USb to my laptop and that is connected into the wall.
@Dennis_Knutson wrote: Why don't you simply ground them? You can buy bnc connectors that short the shield to the center conductor or simply do it yourself.
It means exactly what it says. You need to understand what a bnc connector and cable are. The outer part of the connector is called the shield and is typically grounded. The center male pin or female plug is the conductor of the signal.
