I do mass flow controllers using laminar flow elements and I am trying to figure out what my total system accuracy is?
You will have to include your pressure standard and probably your temperature standard as well. The best thing to use if you have it is a bell system or even better dhi mol-blocs.
I was looking at the BIOS system not sure if anyone on here has any experience with that? It is the piston system there best is supposed to be +-.15 % accuracy.
I don't have any experience with the ML-800 system that you are talking about, but I do have a good few years of working with the ML-500 under my belt. We bought our system just after the ML-500 came out and well before the ML-800 was available.
I love ours. From the best I can determine it is very repeatable and stable. Very nominal drift between calibration and what drift I've seen is almost always in the pressure sensor. I believe the ML-800 has an improved pressure sensor but I am not positive about that.
I've never liked laminar elements and I've always been skeptical of the mol-bloc, though I've never had any experience with it.
We had a flow computer. The elements, temp, pressure......all was figured into the computer. I liked it much better than figuring all that crap individually.