Low cost data acquisition systems based on standard interfaces

A very simple solution to implement data acquisition and actuation systems for educational or field applications in data monitoring and control is presented. Using the serial and the parallel interfaces of the PC computer, different A/D and D/A low cost modules were developed. The parallel versions, mainly for laboratory applications, can be addressable so that 8 different modules can be used simultaneously. The serial interface series has two versions: stand-alone and addressable. The latter needs a RS232C to RS485 converter and presently can interface up to 128 modules at the same time. Software drivers for C/C++, LabView, Visual Basic and MATLAB/Simulink were developed expanding the variety of situations in which the modules can be used. An example of the possibilities of application of the concept is presented. It is a simple but real laboratory facility where the temperature control can be experienced. It is shown how quick and easily the hardware can be accessed by powerful software such as MATLAB including interactive and dynamic graphical interfaces. At this moment the approach is successfully used in the teaching of control theory, although it is possible to use it soon in real-world applications