Supervisory Control and Data Acquisition (SCADA) is a process control system that enables a site operator to monitor and control processes that are distributed among various remote sites. A properly designed SCADA system saves time and money by eliminating the need for service personnel to visit each site for inspection, data collection/logging or make adjustments. Supervisory control and data acquisition is used to describe a system where both data acquisition and supervisory control are performed. Mobile Supervisory Control and Data Acquisition (referred to as Mobile SCADA) is the use of SCADA with the mobile phone network being used as the underlying communication medium. GSM is a wireless communication technology; most popular today for transmitting data anywhere in the world through SMS with the help of mobile phones. Typically SCADA systems include the following components:
- Operating equipment such as pumps, valves,conveyors and substation breakers that can becontrolled by energizing actuators or relays. Instruments in the field or in a facility that sense conditions such as pH, temperature,pressure, power level and flow rate.
- Local processors that communicate with the site’s instruments and operating equipment. This includes the Programmable Logic Controller (PLC), Remote Terminal Unit (RTU), IntelligentElectronic Device (IED) and Process Automation Controller (PAC). A single local processor may be responsible for dozens of inputs from instruments and outputs to operating equipment.
- Short range communications between the local processors and the instruments and operating equipment. These relatively short cables or wireless connections carry analog and discrete signals using electrical characteristics such as voltage and current, or using other established industrial communications protocols.
- Host computers that act as the central point of monitoring and control. The host computer is where a human operator can supervise the process; receive alarms, review data and exercise control.
- processors and host computers. This communication typically covers miles using methods such as leased phone lines, satellite, microwave, frame relay and cellular packet dataLong range communications between the local