I am wondering if anyone can give me an example or explain to me how to read a signal from a transducer and read/send signal to a valve using a C language programming.
Well that is a tall order with so little information.
Several questions spring to mind:
What type of transducer is it.
What type of computer is it connected to - PC, or some toher type.
Asuming a PC what port would it be using - serial/Parallel/USB - some other type of port.
Your question is way too vague to give a sensible answer.