Supervisory control and data acquisition or SCADA
Supervisory control and data acquisition or SCADA is a software architecture comprising computer systems, networks and graphical user interfaces (GUI) for top-level process supervision, while also containing other peripheral devices such as programmable logic controls (PLC), digital signal processors (DSPs), and discrete real-time communication (RTC). Basically, it is an application where multiple function keys or commands are sent to a computer terminal and the computer processes these keys or commands in response. The goal of this architecture is to let the computer perform work that is already programmed by the user. The beauty of this approach is that it is simple: the user just needs to specify what he wants the computer to do. This type of control can be used for a variety of tasks including fault injection, fault detection, rescheduling, and even dynamic scheduling.
Supervisory control and data acquisition can either be input (manually) or output (electronically). Input control SCADA systems control the operations inside the machines, while output control SCADA systems provide information to the human operator. The output systems can either be active (agents inside the machines) or passive (human operator). These types of control systems can be very complicated. For example, an active SCADA system can be controlled by a human operator through a keyboard and mouse, while a passive system can be controlled by a computer. These complexities are inherent in all SCADA systems.
Supervisory control and data acquisition can either be networked (using a local area network) or localized (uses of a Wide Area Network). Networks often used for SCADA are VPN, Local Area Network, WAN and Ethernet over firewall. Local Area Networks (LANs) connect computers via different means like router, wireless network, ISDN and so on. On the other hand, Wide Area Networks (WANs) connect computers using the internet or other high-speed technologies such as cable, DSL and so on.
In the past, a supervisor monitored a distributed system via desktop computer, laptop or remote access device. With the advent of the supervisory control and data acquisition, a user can monitor a centralized system from a distance. Today, SCADA is used for military intelligence, traffic management and supply chain control. There are three primary components of SCADA systems; sensors, actuators and software.
One of the most important benefits of using supervisory control and data acquisition is reliability. Unlike traditional systems monitoring or controlling only machines or locations, SCADA solutions can detect problems at any time and can recover from failures to the business system. This helps increase the productivity of the organization. Supervisory control and data acquisition systems are very reliable since they can detect faults that can lead to catastrophic outcomes. They also make use of distributed control to ensure smooth operation.