Industrial control systems are a general term used to describe different types of control systems and related instruments, including equipment, systems, networks, and controls used to operate and automate industrial processes. The function of each industrial automation system varies by industry, aiming to process tasks efficiently electronically. Below is an introduction to some types of industrial automation control systems.
Distributed Control System (DCS)
While the term DCS is generally applicable to any system with distributed rather than centralized controllers, in the power generation and petrochemical process industries, it refers to a specific type of control system capable of executing high-speed, complex analog process control algorithms and providing routine monitoring, reporting, and data logging functions. In most applications, the input and output modules of the automated control system are distributed throughout the facility, but the control processor itself is located in a central location near the control room. These systems typically use proprietary hardware, software, and communication protocols, requiring replacement parts and technical support from the original equipment manufacturer (OEM).
Remote Terminal Unit (RTU)
A remote unit (RTU) is a system widely used in the power, gas, and water supply industries because they require monitoring and surveillance across long geographical distances. At remote terminals, it primarily provides monitoring and control capabilities at unattended sites such as substations, metering stations, pumping stations, and water towers. They communicate with a central station via telephone lines, fiber optics, radio, or microwave transmission. Monitored sites tend to be relatively small, and RTUs are typically used primarily for monitoring and limited control. The hardware and software are proprietary, using proprietary or open protocols to transmit data to the central station.
Programmable Logic Controller (PLC) System
PLCs can be networked to achieve data sharing and provide centralized monitoring functions. In industry, control systems composed of networked PLCs are replacing factory DCS and RTU-based systems. They were developed for factory automation and traditionally excelled at high-speed discrete control, but now also offer analog control capabilities. The hardware of industrial automation control systems is proprietary, but the control software and network communication protocols are open, allowing system configurations, programming, and technical support for specific manufacturers' equipment to be obtained from many sources.
Supervisory Control and Data Acquisition (SCADA)
A general term for computerized systems that can acquire and process data and apply remote operation and control. Typical applications include power transmission and distribution and pipeline systems. They address unique communication challenges (e.g., latency, data integrity) arising from the diverse media used (e.g., telephone lines, microwave, and satellite). They are typically shared rather than dedicated.
Remote Terminal Unit (RTU)
Microprocessor-based electronic devices are used to connect various hardware devices to a distributed control system. A remote terminal unit (RTU), also known as a telemetry remote unit or a remote control remote unit, transmits sensor data from the input stream to the output stream in the control loop for transmission to the ICS centralized command.
Industrial control systems are a crucial component of automation systems. Various types of closed-loop control techniques ensure that process variables adhere to the setpoint. In addition to this fundamental function, industrial automation systems utilize various other functions, such as calculating the control system setpoint, plant startup or shutdown, monitoring system performance, and equipment scheduling.
