Industrial control system (ICS) is a collective term that refers to any device, network, or system and the associated instrumentation that’s used to operate or automate common industrial processes. ICSs are used in virtually every industrial sector and in critical infrastructure industries, including, but not limited to, energy, manufacturing, transportation, and water treatment.
There are several kinds of ICSs. They vary in size and complexity and are built with different industries and different tasks in mind. Some of the most common include Supervisory Control and Data Acquisition (SCADA) systems, Distributed Control Systems (DCSs), Programmable Logic Controllers (PLC), and a handful of others. Read on to learn more about the eight main types of industrial control systems and what they do.
The History of Industrial Control Systems
Automated machines may seem like a fairly recent invention, but closed loop systems actually date back to 1620 and automated machines have been around since ancient times. Digital control systems, meanwhile, were developed in the mid-20th century. The first industrial control systems were invented not long afterwards.
Originally, industrial plants were operated via local control panels that were dispersed around the plant and controlled by operators. Because they were spread all around the plant, it was hard for operators to communicate with each other, and the control process was often messy and convoluted.
Eventually, things were moved to a central control room. The controls sat behind panels in the control room and controlled machines and processes by transmitting pneumatic or electric signals back-and-forth. This was an improvement over previous methods, but still inflexible and not particularly convenient.
After the advent of electronic processers, controllers were replaced with computer-based algorithms that had their own control processors and were hosted on a network of input and output racks. This is how distributed control, and, consequently, distributed control systems (DCS) were invented.
DCSs flourished in industries where processes were often continuous, but for industries that required more combinatorial and sequential logic, they weren’t as effective—so PLCs were invented for the automotive industry and other similar industries. SCADA was invented around the same time for industries that needed to gather information remotely from various sources. Other ICSs were created to accommodate the needs of other industries, which gave us the eight main types—plus various others—that exist today.
The Types of Industrial Control Systems
Supervisory Control and Data Acquisition (SCADA)
SCADAs are computer systems that can gather data, process data, and apply operational controls over long distances. They’re designed to streamline the communication process across various communication media.
Common applications of SCADA include microwaves, phone lines, pipeline systems, power transmission and distribution systems, and satellites.
Distributed Control System (DCS)
DCSs are industrial control systems that can be individually controlled due to the way they’re distributed. They consist of a series of controllers, sensors, and specialized computers.
Each of these components serves a unique function. One component might handle graphical display, for example, while another component handles data acquisition and storage.
These various components communicate with a centralized control computer network. The DCS uses the data from this network to make automated, real-time decisions.
Common applications of DCS include agricultural applications, automobile manufacturing, chemical plants, mining applications, nuclear power plants, sewage treatment plants, and water treatment plants.
Programmable Logic Controllers (PLCs)
PLCs are solid-state control systems that have a user-programmable memory used to store the instructions for implementing functions such as I/O control, PID control, sequential control, and arithmetic, counting, and timing mechanisms.
They have a sturdy construction that allows them to hold up against extreme weather conditions and temperatures as well as electrical noises and vibrations.
Common applications of PLCs includeescalators and lifts, traffic controls, washing machines, ball milling, shaft kin, and coal kin in cement manufacturing, glass processing in the glass industry, and IMCS in the plastic industry.
Programmable Automation Controllers (PACs)
PACs are automation controllers that are used to provide automated equipment with complex instructions. Think of them as an advanced version of PLCs with superior connectivity and control options.
PACs consist of five main elements, including adaptable software tools, enterprise network compatibility, modular design, a multi-discipline development platform, and multi-domain functionality.
Common applications of PACs include logic systems, motion systems, process control, and vision systems.
Remote Terminal Units (RTUs)
RTUs (also known as remote units of telemetry or remote units of telecontrol), like IEDs, are microprocessor-based electronic devices. They’re used in ICSs to connect hardware to other control systems such as SCADAs or DCS. They take sensor data and move it through input and output streams in the control loop, which transmits the data to a centralized ICS.
Common applications of RTUs include air traffic equipment, environmental monitoring systems for emissions and pollution, oil wells, pipeline pump stations, and warning sirens.
Industrial Automation and Control Systems (IACS)
IACS are made up of various solid-state, electromechanical, and mechanical devices. They use sensors, smart devices, and software that translates sensor information into control outputs to track and control certain processes and machinery.
Common applications of IACS include automotive, autotransformers, facility management, motor controls, reactors, transducers, and transportation.
Intelligent Electronic Devices (IEDs)
The next and second-to-last type of industrial control system is the Intelligent Electronic Device, or IED. IEDs are microprocessor-based electronic devices (ex. regulators or circuit controls) that are used for communications, control, metering, monitoring, and protection. They use industrial protocols such as real-time Ethernet or Fieldbus to communicate with external devices.
Common applications of IEDs include automotive manufacturing, food processing, pharmaceutical manufacturing, sewage treatment plants, and water treatment plants.
Human-Machine Interface (HMI)
HMIs are the dashboard or screen used to monitor and control machinery. Essentially, they’re a piece of software or hardware that’s loaded onto and viewed on a computer.
Common applications of HMIs include automotive appliances, control rooms, digital signage, handheld devices, and medical appliances.
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