부산대학교 도서관

The liquid level measurement and transmission of signal safely up to the control room for further processing is important for the process industry. In this article, an electronic float and a signal conditioning circuit have been used for measuring the height of the liquid level in terms of electrical signals. An electrooptic amplitude modulator has been used to change an electrical signal matching to the liquid level information into an optical signal. Mach-Zehnder interferometer (MZI) has been used as an amplitude modulator. The optical signals contain information of the height of the liquid and transmit safely up to the remote location such as control room in the inflammable process industry. The optical signal is converted to electrical signal in the remote location by the demodulation technique and then sent to an opto-isolator circuit followed by the PC through a data acquisition system (DAS) card. The signal is sent to PC for further processing in the process industry. The necessary theoretical and mathematical equation has been derived for understanding the operation of the system. The simulation and experiment results are presented in this present article.