Design and implementation of a real time PC based flow indicating controller and optical transmitter

PC based measurement and control are important to the industrial automation. The signal transmission through a hazardous region in the form of optical signal is preferred more than the electrical signal. In the present work, an experimental study has been made with low cost modified optically isolated Rotameter based flow transmitter and flow control system. This flow indicating controller has been designed using modified LVDT based Rotameter, PC based controller NI DAQ and LabVIEW software. An analog signal-conditioning and flow control circuit is developed. The same was calibrated with flow measuring test rig with a standard available industrial flow meter. The output of the opto-isolator circuit has been shown in a PC and the flow rate is controlled to a desired value using LabVIEW software. The output of the Rotameter is sent to the remote location through optical fiber cable and converted to electrical signal using optoelectronics converter. The experiment has been performed and results are presented in the paper. The experimental result follows the theoretical equations. Simulation is done on optical flow transmitter. It has been observed that variation of LVDT output voltage and the characteristic of the transducer and PC based controller are all linear in nature.