Remote Control Laboratory Using EJS Applets and TwinCAT Programmable Logic Controllers

This paper presents a new methodology to develop remote laboratories for systems engineering and automation control courses, based on the combined use of TwinCAT, a laboratory Java server application, and Easy Java Simulations (EJS). The TwinCAT system is used to close the control loop for the selected plants by means of programmable logic controllers (PLCs) deployed in PCs with the TwinCAT run-time tool. EJS is used to develop the laboratory front-end applets that let teachers and students parametrize and observe the behavior of the PLCs from any computer. The laboratory Java server application establishes the connection between the EJS applets and the PLCs, fulfilling the TwinCAT connection requirements while ensuring an individualized access to each PLC. This paper also shows how the practical work in some undergraduate control courses at the Complutense University of Madrid, Spain, already uses the TwinCAT PLC + Java server + EJS applet strategy to provide real-time support to the controllers, remote individualized access to the experiments, and a user-friendly graphic controller interface for the students.