I had connected the analog voltage output to the analog input pin of NI USB 6008. However, the voltage shows no difference when the distance varying.
Trying the other ways of getting the analog output data, eg. time flight etc., but don't know how to start it.
I don't see the [manual] (https://info.bannerengineering.com/cs/groups/public/documents/literature/181483.pdf) mentioning the analog output but the PNP output. Have you tried to capture the output signal with DMM or scope?