The term “industrial control system,” or “ICS” for short, refers to a collection of various types of control systems and associated instruments that operates and automates industrial processes. It includes all related devices, systems, networks, and controls.

Each ICS has a different function depending on the industry it’s used in. In general, ICSs are built to manage electronic tasks efficiently. Today, ICS devices and protocols are used in nearly every industrial sector and critical infrastructure, such as the manufacturing, transportation, energy, and water treatment industries.

Other interesting terms…

Read More about an “Industrial Control System

What Are the Types of Industrial Control Systems?

While there are different kinds of ICSs, probably the most common are supervisory control and data acquisition (SCADA) systems and distributed control systems (DCSs). Each type is described in more detail below.

SCADA system

This ICS does not provide its users with full control. It focuses instead on giving user control only on the supervisory level. SCADA systems comprise various devices like programmable logic controllers (PLCs) and commercial hardware modules typically distributed in multiple locations. They can acquire and transmit data and have built-in human-machine interfaces (HMIs) that allow users to perform centralized process input and output monitoring and control. 

SCADA systems are commonly used in industries involving pipeline monitoring and control, water treatment and distribution, and electrical power transmission and distribution.


This ICS controls production systems found in a single location. A DCS sends a setpoint to the controller to instruct valves or actuators to operate while maintaining the desired setpoint. The setpoint is, of course, the desired or target value for an essential variable or process value of a DCS. Each DCS uses a centralized supervisory control loop to manage several local controllers or devices that are part of an overall production process. 

DCSs allow industries to quickly access production and operation data to reduce the impact of a single fault on the overall ICS. They are commonly used in the manufacturing, electric power generation, chemical manufacturing, oil refinement, and water and wastewater treatment sectors.

Actual ICS implementation

This ICS environment is often a mix of DCSs and SCADA systems.

What Makes Up an ICS Environment?

Several components are necessary to make an ICS work. These include:

  • IT and operational technology (OT) devices: OT includes hardware and software systems that monitor and control physical devices in the field. Devices that monitor the temperature in industrial environments are examples of OT devices. While IT/OT convergence gives organizations better supply chain visibility, it also provides cyber attackers easier access to IT and OT devices.
  • PLC: This refers to a piece of hardware used as an ICS control component in both DCSs and SCADA systems. They allow users to manage processes locally or on their HMIs (read more on HMIs below) using feedback control devices like sensors and actuators as input providers.
  • Remote terminal unit (RTU): This is a microprocessor-controlled field device that receives commands and sends information back to the master terminal unit (MTU). The MTU is the ICS server or supervisory controller.
  • Control loop: This is made up of hardware, including PLCs and actuators. It interprets signals from sensors, control valves, breakers, switches, motors, and other similar devices and transmits data to the controller so it can perform a task or complete a process.
  • HMI: This is a graphical user interface (GUI) application that lets a human operator interact with the controller hardware. It also displays status and historical data that ICS devices gather. It monitors and configures setpoints, controls algorithms, and adjusts and establishes parameters in controllers as well.
  • Remote diagnostics and maintenance system: This identifies and prevents abnormal operations of failures in ICS environments.
  • Control server: This hosts the DCS or PLC supervisory control software and communicates with lower-level control devices.
  • SCADA server, MTU, or supervisory controller: This device issues commands to RTUs in the field.
  • Intelligent electronic device (IED): This refers to a smart device that can acquire data, communicate with other devices, and perform local processing and control tasks. Its use in SCADA systems and DCSs lets controls set at the local level to execute automatically.
  • Data historian: This is a centralized database that logs all of an ICS environment’s process information. It then exports said data to the ICS owner’s information system (IS). The data is then used for process analysis, statistical process control, and enterprise-level planning.

As we’ve seen in this post, ICSs are important to supporting critical infrastructures and maintaining security. Without them, we won’t have clean water or electricity in our homes. Car and other machines will take a longer time to make, and so on. That is why ICS operators should prevent attacks against their networks at all costs.