What is SCADA system ? How does SCADA systems work?

What is SCADA Systems

Supervisory Control and Data Acquisition (SCADA) systems are a crucial component of modern industrial, infrastructure, and facility processes. They are used to monitor, control, and automate various types of operations across numerous industries. SCADA systems play a vital role in critical infrastructure such as water treatment facilities, electric power generation and distribution, gas and oil pipelines, and transportation systems, among others.

What is SCADA Systems

Core Components of SCADA Systems:

  1. Human-Machine Interface (HMI): The HMI is the graphical user interface through which operators interact with the SCADA system. It provides visualizations of the monitored process, displays real-time data, and allows for manual control inputs and adjustments.
  2. Supervisory Computer System: This central system gathers data on the process and sends control commands to the field connected devices. It often involves sophisticated software applications for process monitoring, data analysis, and decision-making support.
  3. Remote Terminal Units (RTUs) and Programmable Logic Controllers (PLCs): RTUs and PLCs are located at remote sites or alongside processes. They perform local data collection and control tasks, then communicate this information back to the supervisory system. While RTUs are traditionally used in SCADA systems, PLCs are increasingly common due to their advanced capabilities and flexibility.
  4. Communication Infrastructure: This includes the network and communication protocols used to connect the HMI, supervisory computers, and field devices. It can range from wired connections (e.g., Ethernet, fiber optics) to wireless solutions (e.g., radio, cellular).
  5. Data Acquisition System: This component is responsible for collecting sensor outputs, process measurements, and other data from the field devices and transmitting them to the supervisory system.

Key Features of SCADA Systems:

  • Real-Time Data Monitoring: SCADA systems provide real-time visibility into the operational status of industrial processes, enabling prompt detection and correction of issues.
  • Control Functions: They can issue commands to connected devices to control various aspects of the process, such as starting or stopping pumps, opening or closing valves, and setting process parameters.
  • Event Logging and Alarming: SCADA systems log events and generate alarms for abnormal conditions, ensuring that operators are alerted to potential issues promptly.
  • Historical Data Collection: They collect and store historical data for trend analysis, operational performance review, and decision-making support.
  • Redundancy and Reliability: Many SCADA systems are designed with redundancy and high reliability to ensure continuous operation, especially in critical infrastructure applications.
  • Scalability: SCADA systems can be scaled to accommodate the size and complexity of the operation, from small facilities to large, multi-site installations.

Applications of SCADA Systems:

SCADA systems are versatile and can be applied in various sectors, including:

  • Utilities: For managing water supply, wastewater treatment, electric power transmission and distribution, and gas distribution.
  • Manufacturing: To monitor and control production lines, machinery, and industrial processes.
  • Transportation: For controlling railway traffic, monitoring pipelines, and managing airports and seaports.
  • Energy: In the management of renewable energy sources, conventional power plants, and the monitoring of smart grids.
  • Public Infrastructure: In the management of bridges, tunnels, and public buildings.

By automating routine tasks, providing real-time data, and enabling efficient process control, SCADA systems enhance operational efficiency, improve safety, and help in reducing costs in the industries they serve.

How does a SCADA system work ?

A SCADA (Supervisory Control and Data Acquisition) system operates by monitoring and controlling industrial, infrastructure, or facility-based processes, providing a crucial layer of management for any large-scale or complex operation. The working of a SCADA system can be broken down into several key steps that involve data collection, data communication, data presentation, and control actions:

How does a SCADA system work ?

1. Data Collection:

  • Field Instrumentation: The process begins with sensors and actuators installed at various points within the industrial process or facility. These devices measure physical quantities like temperature, pressure, flow rate, and more, or act upon the system based on received commands.
  • Remote Terminal Units (RTUs) and Programmable Logic Controllers (PLCs): These devices are located in the field near the sensors and actuators. RTUs collect data from sensors, execute control commands by operating actuators, and interface with the SCADA system. PLCs, which are often used interchangeably with RTUs in modern systems, perform similar functions but with more complex logic capabilities.

2. Data Communication:

  • Communication Network: The collected data is transmitted to the central supervisory system via various communication protocols and networks, which can include wired (Ethernet, fiber optics) and wireless (radio, cellular) technologies. This network must be reliable and often includes redundancy to ensure continuous operation, especially in critical systems.
  • Data Handling: The supervisory system receives data from multiple RTUs and PLCs. This data is processed, logged, and stored for real-time monitoring, historical analysis, and future reference.

3. Data Presentation:

  • Human-Machine Interface (HMI): The processed data is presented to the operators through HMIs, which display graphical representations of the process, such as schematics, charts, and digital readouts. The HMI allows operators to visualize the operational status of the system in real-time, making it easier to monitor and identify issues.
  • Alarms and Alerts: The SCADA system is configured to recognize predefined conditions that signify operational anomalies or system failures. When such conditions are detected, the system generates alarms or alerts to notify operators, prompting immediate attention and action.

4. Control Actions:

  • Operator Commands: Operators can issue commands through the HMI to control the process. These commands are sent back to the RTUs and PLCs, which then execute the desired actions by controlling the actuators in the field.
  • Automated Control Logic: In some cases, control actions are automated based on the logic programmed into the PLCs or the supervisory system itself. This can include routine operations, such as starting or stopping pumps at set times, or dynamic responses to certain conditions, like adjusting valve positions in response to changes in pressure or flow rate.

5. Event Logging and Reporting:

  • Event and Data Logging: The SCADA system continuously logs operational data and events, providing a historical record of the system’s performance, incidents, and operator actions.
  • Analysis and Reporting: This data can be analyzed to identify trends, improve system efficiency, plan maintenance, and generate reports for compliance and operational review.

In essence, a SCADA system integrates data collection devices, communication networks, data processing software, and user interfaces to provide a comprehensive solution for monitoring, controlling, and optimizing industrial and infrastructure processes. This integration enables efficient operations, enhances safety, and supports decision-making by providing a real-time and historical overview of the entire system.

Specifications when select a scada system

When selecting a SCADA (Supervisory Control and Data Acquisition) system, it’s essential to consider a range of specifications and requirements to ensure the system meets the operational needs of your facility or infrastructure. The right SCADA system should not only accommodate current needs but also be flexible and scalable to adapt to future changes and expansions. Here are key specifications and factors to consider:

1. System Scalability and Flexibility:

  • Size and Expansion Potential: Consider the current size of the operation and future growth. The SCADA system should be scalable to accommodate additional processes, devices, and data points.
  • Modularity: A modular system allows for easier expansion and customization, enabling you to add functionality as needed without overhauling the entire system.

2. Compatibility and Integration:

  • Hardware Compatibility: Ensure the SCADA system is compatible with existing and potential future hardware, including PLCs, RTUs, sensors, and actuators.
  • Software Integration: The system should integrate well with other software tools used in your operations, such as ERP systems, maintenance management software, and data analytics platforms.

3. Communication Capabilities:

  • Network Infrastructure: Consider the types of communication networks supported (wired vs. wireless, Ethernet, serial, etc.) and ensure they align with your infrastructure.
  • Protocols: The SCADA system should support standard and industry-specific communication protocols to ensure seamless data exchange with various devices and systems.

4. Data Collection and Processing:

  • Data Handling Capacity: Assess the system’s ability to handle the volume of data generated by your processes, including data collection frequency, processing speed, and storage capabilities.
  • Real-time Performance: The system should provide real-time monitoring and control capabilities with minimal latency to ensure timely decision-making and response.

5. Human-Machine Interface (HMI):

  • User Interface: Evaluate the usability and intuitiveness of the HMI. It should provide clear visualizations, easy navigation, and customizable dashboards to meet the needs of different users.
  • Accessibility: Consider the need for remote access capabilities, mobile device support, and multi-user environments.

6. Reliability and Redundancy:

  • System Uptime: Look for systems with high reliability and minimal downtime. This is crucial for continuous process industries and critical infrastructure.
  • Redundancy Options: The system should offer redundancy at critical points (servers, communication links, power supplies) to ensure continuous operation in case of a failure.

7. Security Features:

  • Data Security: Assess the system’s security features, including user authentication, encryption, and protection against cyber threats.
  • Compliance: Ensure the system complies with relevant industry standards and regulations for data security and privacy.

8. Support and Maintenance:

  • Vendor Support: Consider the level of technical support and training provided by the vendor, including availability, responsiveness, and expertise.
  • Maintenance Requirements: Understand the maintenance needs of the system, including software updates, hardware servicing, and overall system upkeep.

9. Cost Considerations:

  • Initial Investment: Evaluate the upfront costs, including hardware, software, installation, and training.
  • Operational Costs: Consider ongoing costs, such as licensing fees, support contracts, and maintenance expenses.

10. Regulatory and Industry Standards:

  • Compliance: Ensure the SCADA system meets industry-specific regulatory requirements and standards, which can vary significantly depending on the sector (energy, water treatment, manufacturing, etc.).

By carefully assessing these specifications and aligning them with your operational needs and goals, you can select a SCADA system that optimizes your processes, enhances efficiency, and provides the flexibility to grow and adapt to future challenges.

Codes and Standards of SCADA system

Codes and standards for SCADA (Supervisory Control and Data Acquisition) systems are crucial for ensuring reliability, safety, interoperability, and security in their design, implementation, and operation. These standards come from various organizations and cover different aspects of SCADA systems, including communication protocols, cybersecurity, system architecture, and data exchange. Here’s an overview of some key codes and standards relevant to SCADA systems:

1. IEC 61131-3

  • Description: Part of the IEC 61131 standard, this section specifies programming languages for programmable controllers (PLCs), which are often integral to SCADA systems. It includes languages like Ladder Diagram (LD), Function Block Diagram (FBD), Structured Text (ST), Instruction List (IL), and Sequential Function Chart (SFC).

2. IEC 62351

  • Description: This standard focuses on the security of network and system communications in power system operations, addressing data and communication security in SCADA systems used in the electrical power industry.

3. ISA-99/IEC 62443

  • Description: Developed by the International Society of Automation (ISA) and adopted by the International Electrotechnical Commission (IEC), this series of standards provides a flexible framework to address and mitigate current and future vulnerabilities in industrial automation and control systems (IACS), including SCADA systems.

4. IEC 60870-5

  • Description: This part of the IEC 60870 standard specifies communication protocols for telecontrol (remote control) systems, including SCADA. It’s widely used for electric power system communications.

5. IEC 61850

  • Description: This standard is for the design of electrical substation automation and is relevant for SCADA systems within the power sector. It defines communication protocols for intelligent electronic devices (IEDs) at electrical substations.

6. DNP3 (Distributed Network Protocol)

  • Description: An open and interoperable communications protocol used in SCADA systems, particularly for utilities like water and electric power. It supports communication between various types of data acquisition and control equipment.

7. Modbus

  • Description: A communication protocol widely used for connecting industrial electronic devices. It’s simple and robust, making it a common choice for linking industrial electronic devices like PLCs in SCADA systems.

8. IEEE 1686-2007

  • Description: This IEEE standard specifies security features for substations’ Intelligent Electronic Devices (IEDs), outlining requirements for device access control, event logging, and secure communications, which are relevant for SCADA systems in the power sector.

9. NIST SP 800-82

  • Description: The National Institute of Standards and Technology (NIST) Special Publication 800-82 provides guidelines for industrial control system security, including SCADA systems. It covers recommended security practices, system architecture design, and risk management.

10. ANSI/ISA-101.01

  • Description: This standard focuses on human-machine interfaces (HMIs) for industrial process automation systems, providing guidance on the design and implementation of HMIs in SCADA and other control systems.

When implementing a SCADA system, compliance with relevant codes and standards is essential for ensuring the system’s functionality, reliability, and security. These standards help in defining best practices and benchmarks for system design, implementation, and operation, ensuring that SCADA systems can meet the demands of modern industrial environments securely and efficiently.

SCADA system manufactures

There are numerous manufacturers worldwide that specialize in SCADA (Supervisory Control and Data Acquisition) systems, offering a range of solutions tailored to various industries including utilities, oil and gas, manufacturing, transportation, and more. Below are some of the leading SCADA system manufacturers, known for their reliability, innovation, and comprehensive solutions:

1. Siemens

  • Products: Siemens offers the SIMATIC SCADA systems, which are highly scalable and can be used for a wide range of applications, from simple visualization tasks to complex SCADA applications.

2. Schneider Electric

  • Products: Schneider Electric provides EcoStruxure™ Plant SCADA and ClearSCADA for efficient and reliable industrial operations, known for their robustness and scalability.

3. ABB

  • Products: ABB offers a variety of SCADA solutions tailored to specific industry needs, including the ABB Ability™ System 800xA, which integrates control, safety, and communication technologies.

4. Rockwell Automation

  • Products: Rockwell Automation provides FactoryTalk® software, which offers a suite of SCADA and HMI solutions designed to optimize industrial operations and enhance productivity.

5. Honeywell

  • Products: Honeywell’s Experion® PKS (Process Knowledge System) offers a unified SCADA platform that integrates process, safety, and business management, suitable for various industrial sectors.

6. Emerson Electric

  • Products: Emerson’s Ovation™ and DeltaV™ systems are designed for process industries and power generation, offering advanced SCADA capabilities for operational excellence.

7. Mitsubishi Electric

  • Products: Mitsubishi Electric provides the MC Works64 SCADA software, offering comprehensive visualization tools and seamless integration with Mitsubishi’s range of automation products.

8. GE Digital

  • Products: GE Digital offers iFIX and CIMPLICITY as part of their Proficy HMI/SCADA suite, delivering flexible and scalable solutions for industrial automation and real-time decision support.

9. Yokogawa Electric

  • Products: Yokogawa’s FAST/TOOLS is a web-based SCADA system designed for real-time operational management and optimized for large-scale deployments in various industries.

10. Inductive Automation

  • Products: Inductive Automation’s Ignition SCADA platform is notable for its versatility and interoperability, with a web-based, modular architecture that allows for customization and integration with various systems and databases.

When selecting a SCADA system manufacturer, it’s important to consider factors such as industry experience, system scalability, integration capabilities with existing hardware and software, cybersecurity features, and the level of support and training provided. Each manufacturer has its unique strengths and specializes in different aspects of SCADA systems, so the best choice will depend on the specific needs and requirements of your operation.

SCADA system


In conclusion, SCADA (Supervisory Control and Data Acquisition) systems are integral components of modern industrial automation, playing a pivotal role in monitoring and controlling infrastructure and process environments across a myriad of industries. These systems enhance operational efficiency, reliability, and safety by providing real-time data collection, visualization, and control capabilities.

When considering the implementation of a SCADA system, it’s important to assess various factors such as system scalability, compatibility with existing hardware and software, communication capabilities, data processing needs, and user interface requirements. Security, reliability, and regulatory compliance are also critical considerations, given the vital role of SCADA systems in managing critical infrastructure and sensitive industrial processes.

Leading manufacturers like Siemens, Schneider Electric, ABB, Rockwell Automation, Honeywell, and others offer a range of SCADA solutions, each with unique features and strengths tailored to different industry needs. Selecting the right SCADA system and manufacturer involves balancing factors such as technological capabilities, industry expertise, cost, and support services.

As industries continue to evolve towards more integrated and intelligent systems, the role of SCADA systems is likely to expand, incorporating advancements in IoT, AI, and data analytics. This evolution will further enhance the ability of SCADA systems to optimize operations, predict maintenance needs, and ensure the seamless integration of various components within industrial ecosystems. The future of SCADA lies in its adaptability and integration with emerging technologies, ensuring that it remains at the forefront of industrial automation and control.

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