What is SCADA (Supervisory Control and Data Acquisition)

What is SCADA (Supervisory Control and Data Acquisition)?

Supervisory control and data acquisition (SCADA) is a type of process control system architecture that enables high-level process monitoring management and control using a computer, network data communication, and graphical human-machine interfaces. SCADA systems communicate with other devices such as programmable logic controllers and PID controllers to interact with industrial process plants and equipment.

The SCADA system collects information and data from processes that are analyzed in real-time. It records and logs data and represents the data collected by various HMIs. This allows process control operators to monitor what is happening in the field, even from a remote location. The operator can also interact with the HMI to control these processes.

Supervisory control and data acquisition (SCADA) systems are integral to a wide range of industries and are widely used for process control and monitoring. SCADA systems are popular because of their ability to control, monitor, and send data smartly and seamlessly. In today’s data-driven world, we’re always looking for ways to use the right data to drive automation and make smarter decisions. The SCADA system is a great way to do this.

The supervisory control and data acquisition (SCADA) system can be run virtually, allowing operators to track the entire process from their location or control room. You can save time by using SCADA efficiently. One such good example is the widespread use of SCADA systems in the oil and gas sector. A large pipeline is used to transfer oils and chemicals within the manufacturing unit. Therefore, safety plays an important role in preventing leaks along the pipeline. If a leak occurs, use the SCADA system to identify the leak. Guess the information and send it to the system, display the information on the computer screen, and alert the operator.

A generic supervisory control and data acquisition (SCADA) system contain both hardware and software components. The computer used for analysis must have the SCADA software loaded. The hardware component receives the input data and sends it to the system for further analysis. The SCADA system contains a hard disk, which records the data, saves it in a file, and then prints it out as required by the operator. SCADA systems are used in a variety of industries and manufacturing units including energy, food and beverage, oil and gas, power, water, and waste management units.

Supervisory Control and Data Acquisition (SCADA) Architecture

In general, Supervisory control and data acquisition (SCADA) systems are centralized systems that monitor and control an entire area. This is a pure software package that sits on top of your hardware. The monitoring system collects data about the process and sends command control to the process. SCADA is a remote terminal unit also called RTU. Most control actions are performed automatically by the RTU or PLC. The RTU consists of programmable logic converters that can be set to specific requirements. For example, in a thermal power plant, the water flow can be set to a specific value or modified according to your requirements.

With the supervisory control and data acquisition (SCADA) system, the operator can change the flow setpoints and enable alarm conditions if the flow is lost and hot, and the condition is displayed and recorded. SCADA monitors the overall performance of the system loop. The SCADA system is a centralized system for communicating with both wired and wireless technologies and Clint devices. SCADA system control can perfectly carry out all kinds of industrial processes.

Hardware Architecture:

A supervisory control and data acquisition (SCADA) station is a server and consists of one PC. The data server communicates with field devices via a process controller such as a PLC or RTU. The PLC is connected to the data server either directly or via a network or bus. SCADA systems utilize WAN and LAN networks. WANs and LANs consist of Internet protocols used for communication between master stations and devices. A physical device such as a sensor connected to a PLC or RTU. The RTU converts the sensor signal into digital data and sends the digital data to the master. The electrical signal is applied to the relay according to the master feedback received by the RTU. As shown, most of the monitoring and control operations are performed by the RTU or PLC.

Software Architecture:

Most servers are used for multitasking and real-time databases. The server is responsible for collecting and processing the data. The supervisory control and data acquisition (SCADA) system consist of a software program for the provision of the trend, diagnostic data, and information management, e.g. B. Schedule maintenance procedures, logistical information, detailed schematics for certain sensors or machines as well as expert systems. This means that the operator can see a schematic of the plant being controlled.

Supervisory Control and Data Acquisition (SCADA) System Work Procedure


These functions are performed by sensors, RTUs, controllers, and communication networks. The sensor is used to collect important information and the RTU is used to send this information to the controller to display the status of the system. Depending on the status of the system, the user can give commands to other system components. This operation is performed by the communication network.

Data Collection

A real-time system consists of thousands of components and sensors. Knowing the status of specific components and sensors is very important. For example, some sensors measure the flow of water from a reservoir to a water tank, and some sensors measure the value of pressure because water is discharged from the reservoir.

Data Communication

Supervisory control and data acquisition (SCADA) systems use wired networks to communicate between users and devices. Real-time applications use many sensors and components that need to be controlled remotely. The SCADA system uses internet communication. All information is sent over the internet using specific protocols. The RTU is used to communicate between the sensor and the network interface because the sensor and relay cannot communicate with the network protocol.

Information / Data Presentation

A typical circuit network has several indicators that can be displayed for control, but real-time Supervisory control and data acquisition (SCADA) systems have thousands of sensors and alarms that cannot be processed simultaneously. The Supervisory control and data acquisition (SCADA) system uses the Human Machine Interface (HMI) to provide all the information collected from various sensors.

Human Machine Interface

The Supervisory control and data acquisition (SCADA) system uses a human-machine interface. Information is displayed and monitored for human processing. The HMI provides access to multiple control units such as PLC and RTU. The HMI provides a graphical representation of your system. For example, it provides a graphic image of a pump connected to a tank. The user can see the water flow and water pressure. An important part of the HMI is the alarm system, which operates according to predefined values.

Applications of Supervisory Control and Data Acquisition (SCADA)

SCADA comprehensively uses features such as flexibility, reliability, and scalability in the automation of complex systems. There are myriad applications in the real world where SCADA is already effective in providing alternative monitoring and control alternatives across a wide range of sectors, from energy production to agricultural systems. SCADA is widely used in various fields from chemistry, gas, water, communication, and power system.

Applications of Supervisory Control and Data Acquisition (SCADA)

Power Generation, Transmission, Distribution

Using the SCADA system, electric utilities detect current and line voltage, monitor circuit breaker activity, and bring sections of the grid online or offline.

Manufacturing Unit

SCADA systems are used to coordinate industrial automation and robots and monitor processes and quality control.

Mass Transportation and Railway Towing

Transportation staff uses SCADA to regulate power for subways, trams, and trolleybuses. Automate rail traffic signals; monitor, and identify trains and buses, control crossing doors

Water, Wastewater Utilities, and Sewage

State and local water utilities use SCADA to monitor and control water flow, tank concentration, pipe pressure, and other variables.

Building, Facility, Environment

Facility managers use SCADA to coordinate HVAC, cooling, lighting, and input systems.

Water Security

Much research is ongoing on how to implement modern SCADA concepts in water treatment plants while minimizing the risk of unauthorized network access (cyber risk is an ongoing issue for large companies). SCADA’s communication network is distributed throughout the water distribution system, as shown in the figure below. PC-based workstations are usually located in the control room processing facility, allowing the operator to see the entire process and take control measures.

In the factory, PLC is used for chemical processing and filters. A local area network (LAN) is used to link the controller to workstations. Remote Terminal Units (RTUs) are used in remote locations and are commonly used in sensitive areas such as pumping stations, storage tanks, valve storage and processing centers. RTU communicates in a wide area network represented by the wireless system shown in the figure below. An important advantage of the SCADA scheme is safety measures and coordination of activities. SCADA systems connected to perimeter surveillance systems can significantly reduce or even eliminate the need for manned patrols.

The SCADA scheme, unlike patrol, can provide continuous monitoring of all locations. You can easily interface with security systems or appliances such as video cameras, motion detectors, touch switches, keypad input devices, card readers, etc. either directly or through a remote terminal unit (RTU) adjacent to the SCADA network. Today’s SCADA systems also provide alarm management when many alarms occur in a short time.

Thermal Power Plant

Most thermal power plants have automatic operational inspections. However, you may need to take manual action. Therefore, the plant is equipped with a monitoring system and an alarm system to alert the plant operator when a particular running para-counter deviates significantly from its normal range. Thermal power plants are in high demand for increased reliability and effectiveness. After regular intervals, the power plant requires ongoing inspection and tracking. When a human employee measures at different stages, there is a chance of error. To improve reliability, automation is needed to improve the efficiency of typical power plants. Automation is established using PLC and SCADA to reduce human worker error. SCADA system is used to monitor the complete process.

Forestry, Pulp, and Paper Industry

The forestry, pulp, and paper industries also rely on the SCADA system. Automation and process control, energy management, drive control, power protection, enclosure systems, and safety make the industry a good candidate for SCADA.

SCADA systems are used throughout the paper supply chain, from within the woodyard to chippers, evaporators, digesters, refiners, cleaners, dryers and presses, and even paper machines. This complex tree-to-paper process is automated end-to-end through the use of established SCADA systems.

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