Design of a simple service oriented supervisory control and data acquisition system
The goal of this paper was to design a simple Service Oriented Supervisory Control and Data Acquisition System (SCADA) that can be used to manage, control and visualize multiple heterogeneous SCADA systems. A three-tier System architecture was designed consisting of Data Access, Service and Presentation Layers. Clients on the presentation layer can communicate with the system backend via SOAP XML or RESTful JSON Web services. The full entity relationship diagram of the database schema is presented in the paper. Message sequence charts are explained in detail for polling and event based notification of setpoint changes. At the end of the paper a simple Web user interface was introduced to demonstrate how modern Web technologies like AJAX and JQuery can be used to build interactive SCADA user interfaces.