Hi kdm,
your LEM sensor needs a constant power supply of +5V and GND so you will connect those pins to the "+5V" and "GND" pins of your USB6008. The sensor "out" pin is connected to an AI of your choice…
I will not be using the +5v of the usb.(because I need to vary power supply and measure current).
That doesn't make sense in any way…
I'm wondering why you are involved in building measurement setups as it seems (to me) you don't have any experience/knowledge in that area…