I believe that the only difference between the 3100, 3130 and 3140 is the cables and the SW disk that comes with it. It is a very nice unit.
I would still like to have a good data logging unit like Zietronix or something. But the only laptop I have is my work one. That is an additional cost above the Zitronix and getting a O2 bung installed.

(I still have to get my skirts painted and installed)
MikeR
Sorry Franc. Didnt mean to hijack your thread.
Back on topic now.