Hi larsmuller,
running my own small-scale software development business in Germany, I have done extensive work in the past involving network communication and RS232 interfacing to measurement equipment - e.g. interfacing to and reading data from an industrial PLC (programmable logic controller), or complex telemetry systems for scientific applications. I have high standards of clean, well-tested code with good performance. I can send you code samples on request.
I would use cross-development from Linux using GCC/MinGW32, programming in C for low memory footprint and maximum performance. You would get a stand-alone EXE file with all necessary library code (if any) included, so there will be no DLL dependencies.
The C code will be mostly standard C + Win32 API, so it is easy to port to other C environments.
This will be a 32-bit executable that will also run on 64bit Windows' via the WoW64 compatiblility layer (which is either a standard component of 64bit Windows or installed by default). For this kind of application, there would be little or no gain compiling for 64-bit mode.
As for perfomance, you will likely have a noticable perfomance penalty for starting a new process for every single value - did you consider making a program to bulk read a larger number of values per call, or calling it as a library function from your master program?
Even if you can simply read values via putty, it might be helpful to have some documentation about the RS232 server and scale device, to make sure timing specs etc. are met.
I would appreciate if you would consider my bid.
Best regards,
Rainer Zimmermann (Lightshed IT Services)