Introduction:
Supervision consists of commanding a process and supervising its working. To achieve this goal, the supervisory system of a process must collect, supervise and record important sources of data linked to the process, to detect the possible loss of functions and alert the human operator. The main objective of a supervisory system is to give the means to the human operator to control and to command a highly automated process. So, the supervision of industrial processes includes a set of tasks aimed at controlling a process and supervising its operation. Supervisory control and data acquisition systems (SCADA) are widely used in industry for supervisory control and data acquisition of industrial processes. The process can be industrial, infrastructure or facility. SCADA system is used to observe and supervise the shop floor equipment’s in various industrial automation applications. SCADA software, working on DOS and UNIX operating systems used in the 1980s, was an alarm-based program, which has a fairly simple visual interface.
The SCADA system usually consists of the following subsystems:
(1) A Man-Machine Interface (MMI) is the apparatus which presents process data to a human operator, and through this, the human operator, monitors and controls the process.
(2) A supervisory system, acquiring data on the process and sending commands to the process.
(3) Remote Terminal Units (RTUs) connecting to sensors in the process, converting sensor signals to digital data and sending digital data to the supervisory system.
(4) Communication infrastructure connecting the supervisory system to the RTUs. In fact, most control actions are performed automatically by RTU or by programmable logic controllers (PLC). Host control functions are usually restricted to basic overriding or supervisory level intervention. For example, a PLC may control the flow of cooling water through part of an industrial process, but the SCADA system may allow operators to
References: * Lakhoua MN. SCADA applications in thermal power plants. International Journal of the Physical Sciences Vol. 5(6), pp. 1175-1182, June 2010 * Lakhoua MN. Application of Functional Analysis Techniques and Supervision of Thermal Power Plants. * Lakhoua MN (2009c). Supervision of a counting system of the natural gas of a thermal power plant. J. Eng. Technol. Res. ISSN: 2006- 9790. Open Access wwJournals. 1(9): 188-193. * http://www.youtube.com/watch?v=rj44AkHmVCo * http://www.scribd.com/doc/25082838/scada