SCADA (Supervisory Control and Data Acquisition)

Supervisory Control and Data Acquisition (SCADA) is a control system architecture comprising computers, networked data communications, and graphical user interfaces for high-level process supervision. These systems are used in industrial processes including manufacturing, production, power generation, fabrication, and refining, as well as in public utilities such as water treatment and distribution, wastewater collection and treatment, oil and gas pipelines, electrical power transmission and distribution, and wind farms.

Purpose and Role

The primary purpose of SCADA systems is to monitor and control a business's industrial processes and systems in real time. It allows organizations to:

  1. Control industrial processes locally or at remote locations
  2. Monitor, gather, and process real-time data
  3. Directly interact with devices such as sensors, valves, pumps, motors, and more through human-machine interface (HMI) software
  4. Record events into a log file


A SCADA system consists of several components. These include:

  1. HMI (Human-Machine Interface): This is the user interface that connects an operator to the controller in a SCADA system. It translates complex process data into understandable visual representations.
  2. SCADA Master Units (also known as Master Terminal Unit - MTU): These are the repositories of real-time or near real-time reported data.
  3. Remote Terminal Units (RTUs): RTUs connect to sensors in the process, converting sensor signals to digital data and sending digital data to the SCADA system.
  4. Programmable Logic Controller (PLC): PLCs are often used in place of RTUs, even though they are both similar, the PLC is more advanced and allows for simple programming.
  5. Communication infrastructure: This provides connectivity between the SCADA central host computer consoles and the field data interface units.


SCADA systems are vital in industrial organizations because they help maintain efficiency, process data for smarter decisions, and communicate system issues to help mitigate downtime.


SCADA systems have evolved through four generations:

  1. Monolithic
  2. Distributed
  3. Networked
  4. Internet of Things


Some of the benefits of SCADA include improving efficiency, processing data, reducing downtime, cost-saving, and control from remote locations.

Pros and Cons

SCADA systems allow industrial organizations to:

  1. Maintain efficiency and communication
  2. Detect system issues to reduce downtime
  3. Save costs by reducing the need for onsite visits through remote control

However, they can also have drawbacks:

  1. Vulnerability to cyber attacks
  2. High initial investment
  3. Dependence on the vendor for software troubleshooting and updates


An example of a SCADA system could be an electric power generation system. The power plant, transmission and distribution, and substations each have PLCs to control the local operations. The SCADA system can monitor the operations of each sector, relay information back to a central location, and even control certain functions of the sectors remotely.

See Also

  1. Programmable Logic Controller (PLC): PLCs, like RTUs, can act as field devices in a SCADA system.
  2. Industrial Control System (ICS): SCADA is a type of Industrial Control System.
  3. HMI (Human Machine Interface): The user interface part of a SCADA system.
  4. Distributed Control System (DCS): While similar to SCADA, DCS tends to be used in more complex control systems within a single location such as a factory.
  5. Industrial Automation: SCADA is a cornerstone technology in the realm of industrial automation.