SCADA (Supervisory Control and Data Acquisition) is software used for industrial automation, as well as real-time control and monitoring of industrial processes.
Control Operations of a SCADA System
A SCADA system typically performs the following control operations:
- Data Collection: SCADA collects data from remote field devices such as sensors and actuators. These sensors transmit the data to the control center for analysis and decision making.
- Monitoring: SCADA monitors the status of systems and processes, then shows real-time data on a human-machine interface for operators to view.
- Control: Based on the received data, the SCADA system makes automated decisions and sends control commands to the field devices to adjust process variables.
- Alerting: The SCADA system generates alerts in response to system anomalies like equipment failures, process deviations or security breaches.
- Reporting: SCADA generates reports based on the collected data. This data provides important information for the analysts to make decisions.
- Remote Access: SCADA allows operators to remotely access and control the system. This can happen either through a direct connection or over a network.
SCADA Architecture
The SCADA architecture consists of several layers that work together to provide a complete solution. Here are the five levels of SCADA architecture:
Level 0: Field Devices
This is the lowest level in the SCADA architecture and includes the physical devices that gather data from the industrial processes. These devices are: sensors, actuators, valves, switches and other components that can measure and control variables like temperature, pressure, flow and levels. The data gathered by these devices is transmitted to the next level in the SCADA architecture, which is Level 1.
Level 1: Local Control Stations
This level consists of local control stations responsible for the control of the field devices. These control stations gather data from the field devices, process it and then send it to Level 2. The local control stations are often programmable logic controllers (PLCs) or remote terminal units (RTUs) that communicate with the field devices.
Level 2: Supervisory Control
This level includes the main SCADA server or supervisory control station that collects and analyzes data from multiple local control stations. The SCADA server receives data from the local control stations, processes it and then provides a graphical user interface (GUI) for operators to monitor and control the industrial processes. The SCADA server also stores historical data, generates alarms and alerts, and provides reporting and analysis tools.
Level 3: Manufacturing Execution Systems (MES)
The third level involves the Manufacturing Execution Systems (MES) which are responsible for the management of the production processes. The MES system is usually used to track orders, schedule production runs and manage inventory. The MES system communicates with the SCADA server to receive data about the production processes and provide this data in real-time to the operators.
Level 4: Enterprise Business Systems
The fourth and last layer includes the enterprise business systems that are responsible for the management of the organization’s business operations. The enterprise business systems consists of the enterprise resource planning (ERP) system and the customer relationship management (CRM) system. ERP manages the financial and accounting data. CRM, on the other hand, manages customer data. The SCADA system communicates with the enterprise business systems to provide data for reporting and analysis.
Components of SCADA Systems
SCADA architecture refers to the overall design and organization of a SCADA system and a typical SCADA architecture includes the following components.
- Field level: The field level includes field devices like sensors, actuators and other devices. These devices monitor and control the physical processes and are connected to RTUs or PLCs.
- Remote Terminal Units (RTUs) or Programmable Logic Controllers (PLCs): RTUs or PLCs collect data from field devices, perform basic processing and control functions, and transmit data to the master terminal unit (MTU).
- Communication network: The communication network is responsible for data transmission between the field level and the master terminal unit. This network can use different communication technologies depending on the system’s needs, such as wired or wireless communication.
- Master Terminal Unit (MTU): The MTU is the main control center for the SCADA system and is responsible for collecting data from RTUs, performing advanced processing and control functions, and presenting data to the operator via an HMI.
- Human Machine Interface (HMI): The HMI is a graphical user interface (GUI) that provides operators with a visual representation of the process that’s being monitored and controlled. Operators can interact with the system, view process data and make control decisions via the HMI.
- Database: A database is used to store historical data and other information collected by the SCADA system. This information can be used for analysis, reporting and decision making.
- Software: SCADA software integrates all components of the system and provides a comprehensive view of the process being monitored and controlled. The software also provides the necessary tools for monitoring, control and analysis.
Examples of SCADA Use
SCADA systems are used in many different sectors and industries. These include electric companies, water and wastewater management, oil and gas exploration, transportation, and manufacturing.
SCADA systems in the electric industry monitor and control the generation, transmission and distribution of electricity.
In the water and wastewater industry, SCADA systems monitor and control water treatment processes such as collection, distribution and treatment of water. In addition, SCADA systems monitor water quality.
In the oil and gas industry, SCADA systems monitor and control oil and gas production processes. These processes include drilling, production, storage, transport, pipeline monitoring and more.
In the transportation industry, SCADA systems monitor and control various transportation systems such as railways, highways and airports.
SCADA systems in the manufacturing industry monitor and control industrial processes such as assembly lines, production facilities and energy consumption.
Benefits of Modern SCADA
- Improved efficiency and productivity
- Increased security
- More flexibility and scalability
- Enhanced data management capabilities
One of the main benefits derived from using SCADA include improved efficiency and productivity. SCADA systems provide operators with the operating systems’ real-time data while also offering them many control functions. Together, these functions enable a company to make informed decisions and react more quickly to process changes, which typically results in higher efficiency and productivity.
SCADA systems also offer increased security by way of real-time monitoring and control capabilities. These functions can help prevent accidents and minimize damage in the event of an incident. In the electric industry, for example, SCADA systems can detect and respond to power outages.
In addition, modern SCADA systems offer higher flexibility and scalability. Here, SCADA systems can be easily integrated into existing processes and expanded if necessary.
Finally, modern SCADA systems offer enhanced data management capabilities including the ability to store and analyze large quantities of process data. Companies can then make informed decisions based on real-time data leading to improved decision making, cost savings and increased operational efficiencies.
