This paper discusses about control of liquid level in a tank which has an external Yokogawa PID controller UT32A and supports serial communication using RS485 protocol with the PC. The present MODBUS RTU communication via Intouch graphical interface is imitated by opencontrolmodbus serial OPC server and MATLAB (as client). Also, the UT32A controller is replaced by a soft coded PID controller in MATLAB. The open loop curve figures and the PID parameters that are calculated are shown in results which can be further used for fault detection and diagnosis
M. Aravind, Harish, V., B. Sree, L. Sai, Sharma, S., and Nag, P. V. Sunil, “Interfacing and PID control of Liquid Level in a tank using MATLAB”, Proceedings of SARC-ITR International Conference. Chennai, pp. pp. 92-95, 2014.