I'm just curious right now because I'm a long way from needing this. A lot of scientific equipment talks with RS232 (example), and you can get Arduino to talk to RS232.
A few questions crop up, for those who have done something like this:
What equipment was it, and what needed to be done?
What special sensors or effectors were used in the application?
Did the professional equipment come with a manual telling you how to interpret / send data along the serial link, or did you have to reverse engineer anything?
Was the programming relatively simple for your purposes, or did you have to dive into (digital) control theory for a proper outcome? (I haven't learned control theory yet so now would be a good time to know.)
Hi. I'm been working a long time in a clinical laboratory. I developed the program which controlls all the gestion of the patients, samples, results and reports. Of course, I had to deal with RS232.
-The equipment I had connected to the main system was Cell counters (at least 3 differet models), Autoanalisers (at least 3 of them also), photometers (2 of them) ans ELISA readers ( a kind of photometers with a specific pourpose). The most of times, we needed only to recover the results of the instruments, understanding you have a way to identify the sample in the data transmitted. In a very particular case, I had to make a bi-directional comunication, in which I had to tell to the machine (a chemistry analiser) what test have to run with each sample.
As the instruments work by itselfs, they don't need any additional circuitery or sensors.
Regarding the documentation, the manuals used to come with de machine doesn't include this info (without some exceptions), but asking to the dealer for technical manuals I always got it without problems.
I'm not sure about your last question. If you are regarding the flow control, it's not a matter (unless you need to do make a really big computational task in the middle of the transmission). The flow control uses to be by software (xon-xoff protocol) unless you are dealing with very old machines which could use hardware protocols.