What Is Supervisory Control and Data Acquisition (SCADA)?

Supervisory control and data acquisition (SCADA) is a comprehensive hardware and software solution that controls and manages high-level industrial processes without human intervention. It works by gathering real-time data remotely to process it and control conditions and equipment. Enterprises also leverage SCADA to make data-driven decisions regarding industrial processes.

The SCADA architecture starts with remote terminal units (RTUs) or programmable logic controllers (PLCs). RTUs and PLCs are microcomputers capable of communicating with industrial components such as factory machines, human-machine interfaces, end devices, and sensors. Data from these components is then transmitted to computers using SCADA software, which processes, distributes, and displays it to operations teams.

Modern players leverage SCADA to remotely or locally control industrial processes and collect, monitor, and process data in real-time. SCADA also enables industrial operators to directly control and manage devices such as valves, sensors, motors, pumps, and other components using human-machine interface (HMI) software. Additionally, SCADA is a handy record-keeping solution, as all data is systematically logged.

Besides this, SCADA solutions allow industrial organizations to use data for more intelligent decision-making, enhancing efficiency and communicating system issues on time to minimize the risk of downtime. For instance, SCADA will swiftly notify the relevant operations teams if a product batch is exhibiting a high rate of error incidence.

The operations team would then be able to pause production and examine the system data collected by SCADA on the HMI. This would help operators determine and address the root cause of the errors and prevent the bad batch from growing in size.

Until the mid-20th century, industrial organizations relied on field personnel to manually control and monitor equipment. However, as the scale at which these facilities operated was enhanced, it became necessary to devise a solution to control equipment remotely. This need led to the introduction of supervisory control through timers and relays.

‘SCADA’ as a term was conceived in the early 1970s. Around the same time, microprocessors and PLCs were seeing a rise in commercial applications, with enterprises increasingly using them to control and monitor automated processes.

The evolution of SCADA began with mainframe computers. Subsequently, distributed systems were used to drive SCADA. However, while they were interconnected, they could not communicate with systems from other vendors.

The next iteration to be introduced was networked SCADA, which featured an open system architecture, enabling communication among systems from different vendors. However, proprietary technologies were still used for data handling, leading to a gap between controls and IT.

Finally, modern web-based SCADA systems enabled users to access real-time operations data from anywhere worldwide. These solutions addressed the shortcomings of previous iterations and allowed for swift, data-driven decision-making. They significantly improved industrial processes’ efficiency, productivity, reliability, and security.

SCADA systems are popular across enterprise types because they can go from simple installations to large, complex configurations. SCADA is critical in many modern industries, including energy & power, manufacturing, food & beverages, oil & gas, water & wastewater, and transportation.

Virtually every industrialized or operationally-intensive organization relies on some SCADA solution to keep things running smoothly. This could be a solution that maintains refrigeration for a restaurant chain, ensures seamless and safe production at an oil refinery, or even keeps track of homeowners’ energy usage.

See More: What Are Haptics? Meaning, Types, and Importance

Before we learn more about the types of SCADA systems, let's familiarize ourselves with the SCADA system architecture.

Generally, SCADA solutions are deployed in a centralized architecture to enable the monitoring and control of a wide area. The ‘core SCADA’ is a software package positioned atop the hardware and serves as a supervisory system.

Remote terminal units are used to collect data and transmit it to a master system, as well as to control machinery according to the instructions received from the master system. Additionally, PLCs can be customized to fulfill specific operational requirements.

For instance, SCADA can help regulate the water flow in an industrial setup. Operators would be able to change the set flow point and set conditions for an alarm to be triggered in case of high temperature or loss of flow. In case of too much pressure is built up in the pipeline, SCADA could even automatically start opening a release valve. Finally, the condition of the operations would be displayed and recorded continuously. SCADA offers end-to-end performance monitoring for any process loop.

A SCADA hardware system can typically be classified into two layers: the client layer and the data server layer. The former enables man-machine interactions, while the latter drives data processes.

RTUs or PLCs enable communication between the devices and data servers in a SCADA setup. PLCs can be connected directly to the data server or linked using networks and buses. The master station and the various devices communicate using either LAN or WAN.

Finally, sensors rely on RTUs or PLCs to convert signals into digital data. The master unit then receives this data and transmits the appropriate feedback back to the RTUs, which apply electrical signals to the devices accordingly.

SCADA processes such as multitasking and real-time database management are handled at the server level. Additionally, SCADA systems typically consist of software for the graphical display of process data (trends); diagnostic information; and data management, such as scheduled maintenance, logistics, detailed schematics for specific devices, and troubleshooting.

These capabilities allow personnel to view a real-time schematic representation of operations. Examples of SCADA software processes include alarm checks, logging, archiving, and calculations.

Now that we’re familiar with SCADA's architectural overview, let's understand the various SCADA system types.

The earliest SCADA systems relied on large minicomputers for processing. Standard network services did not exist then, which meant SCADA solutions were generally independent systems with no network interconnectivity.

Communication protocols were strictly proprietary. A backup mainframe system connected to all the RTU sites was the preferred setup for system redundancy. This setup would be activated in case the primary mainframe system failed.

In this type of SCADA, information and command processing are decentralized. Distribution occurs across stations connected using LAN, and data sharing occurs near-real time.

A specialized station is assigned for each task, which helps in cost reduction as compared to a monolithic SCADA. Network protocols are still proprietary, so determining SCADA installations’ security is not easy. However, system security was generally overlooked when this SCADA type was popular.

Networked SCADA went one step ahead of the distributed architecture, with complex SCADA systems being reduced to their most basic components and linked using open communication protocols.

In a networked design, SCADA systems can be distributed across several local area networks. This is known as a process control network (PCN) and is usually spread across a wide geographic area. A networked SCADA could simply be a setup with several distributed SCADAs operating in parallel, with one historian and supervisor. Such a setup is cost-effective, especially for large-scale systems.

Finally, web-based SCADA systems enable users to view and exchange data and control processes in a location-agnostic manner using a web SOCKET connection. A web SCADA system typically uses an internet browser as its graphical user interface (GUI). This type of SCADA is known for its simplified client-side deployment. Users can access the system from most platforms, including servers, personal computers, and smartphones.

Now that we’re clear about the types of SCADA systems, let's understand the components included in these types.

Components of SCADA

The supervisory controller, also called the master terminal unit (MTU), plays the role of a central communication server. It is located in the control center and manages information exchange between the human-machine interface and the RTUs, sensors, PLCs, and other devices.

A single personal computer could satisfactorily serve as the supervisory controller in a smaller SCADA configuration. However, the master terminal unit for larger SCADA deployments typically includes numerous servers, distributed software applications, and measures for disaster recovery. Such a system may use hot-standby measures to ensure that critical industrial processes remain unaffected in case of a system failure.

A remote terminal unit (RTU), or a remote telemetry unit, is an electronic device used for remote telemetry and process control. These microprocessor-based devices are linked with transmitters, sensors, monitors, and other devices at the remote site.

RTUs collect and transmit data to the control center, where it is monitored and processed. Data transmission between RTUs and the central station typically occurs when using serial ports such as RS232.

A programmable logic controller (PLC) is a solid-state electronic device that can control system equipment and processes by replacing the RTU. It is linked to the sensors and converts their output into a digital signal.

A PLC features a simpler design and a more straightforward installation process than an RTU. PLCs are also more reliable and economical. Additionally, they are more compact and take up less space than RTUs. Finally, troubleshooting is easy and swift in case of errors.

A human-machine interface (HMI) displays information usually as a graphical representation of the SCADA system for monitoring and control by human operators. Employees use HMIs to access control units such as PLCs and RTUs.

HMIs are ideally designed to be simple and intuitive. For instance, a graphical representation of a pump connected to a water tank would be visible on the HMI, and the human user would be able to view the real-time flow of the water and its pressure.

The alarm system is critical to an HMI system and can be triggered based on predefined values. In the water tank example, a human operator could set the water level alarm at 80% and 90%. The alarm would give a standard warning once the water level crosses 80%. A critical alarm would be triggered if the water level crosses 90%, and a release valve would automatically open.

Intelligent electronic devices include microprocessor-based controllers, regulators, and relays. These devices are capable of serial communications with the other devices within the SCADA system.

Intelligent electronic devices can transmit and receive data from external devices and control or be controlled by them. External devices include transducers, relays, control units, and similar devices.

A network management server (NMS) monitors the network hardware and software for the SCADA system. The network administrator and NMS are responsible for managing individual network components.

NMS records data from remote components, which is then reported to the system administrator. Functions performed by NMS include device monitoring, performance analysis, device discovery & management, and the analysis of alerts & notifications.

SCADA systems leverage a mix of radio, direct-wired, and internet connections for data transfer. In the case of large-scale deployments, such as in power stations and railways, ONET or SDH may also be used.

HMI and MTU use programming to generate maps and diagrams to provide critical information on regular operations and event failures. Commercial SCADA systems generally use C programming or a derived programming language.

See More: What Is Telematics? Meaning, Working, Types, Benefits, and Applications in 2022

SCADA systems are an indispensable part of most modern-day industrial setups. However, they are not flawless. As such, it is crucial to understand more about the pros and cons of SCADA.

Pros and Cons of SCADA

Let's begin by looking at the pros of SCADA solutions.

SCADA systems keep industrial operations secure and streamlined by providing real-time information on the status of all critical devices and processes. Thanks to SCADA, operators can swiftly identify and address potential issues, thus ensuring robust business continuity.

SCADA provides a centralized interface for operations personnel to control and monitor all critical devices and processes from one location. Operations teams can swiftly and efficiently adjust any part of the unified system.

SCADA systems are, by design, highly reliable and efficient. SCADA drives the continuous operation of critical processes, which is vital for ensuring the reliability of industrial operations. SCADA systems can continue operating even during component failure or other system errors.

Further, SCADA automates several crucial tasks that are part of the monitoring and controlling of large-scale operations. By removing the reliance on human intervention and, thus, the possibility of human error, SCADA enhances efficiency and improves process speed and accuracy.

Finally, SCADA systems come with support for remote access functionalities. Operations personnel can use SCADA to control and monitor industrial processes from any secure device with a reliable internet connection. This is especially useful for managing and monitoring hard-to-reach or high-risk equipment.

SCADA systems have many essential pros. However, they also have some noteworthy cons.

The immediate consideration faced by enterprises adopting a SCADA solution is its high cost. SCADA deployments can be cost-intensive because they usually need several units of specialized hardware, customized software, and the training of human operators for day-to-day usage and regular maintenance.

Besides this, SCADA systems are usually critical for industrial operations. Therefore, any form of downtime or failure in these systems can prove to be expensive. This is because repairs would be cost-intensive, as would the downtime cost of shutting down the affected processes.

Without the proper training, SCADA systems can be fairly tricky and complex to use. A SCADA deployment requires specialized knowledge for operators to use it effectively. Even well-trained operators must conduct complex maintenance operations quickly and efficiently to keep the system running. Responding to problems can be tricky, as SCADA configurations — hardware and software — are usually complex in design.

Apart from this, a SCADA configuration is typically customized according to the exact industrial environment it controls and manages. This makes these solutions difficult to upgrade or modify once deployed. Doing so generally requires specialized expertise, and even then, users need to be prepared for potential disruptions to their operations.

SCADA systems are not immune to cyber-attacks. The cybersecurity risk in these solutions arises because SCADA is connected to networks such as LAN, WAN, or the internet. If correct network security practices are not followed, SCADA deployments can be vulnerable to unauthorized access. This could lead to unwanted control or manipulation of industrial processes, which can risk life and property.

See More: What Is Utility Computing? Definition, Process, Examples, and Best Practices

SCADA has become indispensable for managing and controlling industrial processes and ensuring seamless and secure productivity. With numerous options in the market today, let's look at some of the top SCADA software solutions.

SIMATIC is a SCADA solution that specializes in plant transparency and maximizing productivity. Its salient features include openness, innovativeness, scalability, and process visualization.

This software comprises several high-performance attributes that allow for the seamless monitoring of automated processes. It is helpful for single-user and distributed multi-user systems that include redundant servers.

The Siemens SIMATIC open system has all the functions typically required for industrial applications. It can visualize highly complex SCADA tasks and applications. Additionally, it comes with a mobile SCADA solution for smartphones and tablets. Users can also extend system functionality using add-ons.

GENESIS64 is an advanced HMI suite for Microsoft Windows and can deliver high performance over standard connectivity such as OPC, Modbus, and BACnet. Using OPC UA technology, it focuses on providing uninterrupted connectivity from building facilities and plant floors to corporate systems.

ICONICS GENESIS64 allows for monitoring real-time data from manufacturing, energy, and business fronts on a centralized visualization dashboard. Other features include an enterprise-wide distributed alarm system, 2D and 3D graphics, the ability to export updated configurations, and historical trends and logs.

CIMPLICITY by General Electric specializes in high-performance HMI optimized for operator efficiency. Apart from its advanced visualization capabilities, this solution is also preferred for its ability to assist in risk reduction for plant management procedures. Its key features include secure data collection, adaptability to different data sources, and robust control and monitoring capabilities. Besides this, the HMI and dashboards support native and HTML5-based visualization.

GE CIMPLICITY also features an in-depth alarm system for anomaly detection. Apart from this, the functionality of this solution can be extended using APIs and scripting for customized configurations and data acquisition. It is also known for its high availability, round-the-clock uptime, and redundancy.

CIMPLICITY offers users an operations dashboard with all the KPIs and compliance data for reporting. It also features an easy setup process as both cloud and hybrid environments are supported.

Adroit Ignite features a sophisticated HMI and high flexibility, scalability, speed, and ease of use. It is built for Microsoft Windows and has advanced functionality for seasoned users. This software is apt for automobile, food & beverage, utility, life sciences, telecommunication, IoT, manufacturing, and building management enterprises.

A key highlight of this solution is its intuitive ribbon toolbar that helps enhance user productivity. Its Operator and Designer applications are online-compatible, making it useful for both on-premise and cloud applications.

Ignition is a powerful and flexible SCADA tool for industrial automation and control. Key highlights include scripting tools, a drag-and-drop designer, and built-in support for numerous industrial protocols.

Java, SQL, and web-based interfaces drive ignition by Inductive Automation. It easily integrates with other systems and supports real-time data visualization and analysis. Robust security and scalability make this solution suitable for projects across scale.

See More: What Is the Internet of Things? Definition, Role, Examples, and Trends for 2022

SCADA is a crucial component of modern manufacturing. It streamlines production, enhances efficiency, and decreases costs. SCADA also improves disaster control, machinery maintenance, and process precision.

Several SCADA software solutions exist in the market, and choosing the right one depends on the specific business needs of an enterprise. The SCADA tool should ensure optimum control over production floors, utility supplies, and other facilities while securing expensive equipment and output.

Did this article help you understand SCADA in detail? Share your views on FacebookOpens a new window , TwitterOpens a new window , or LinkedInOpens a new window . We’d love to hear from you!

Image Source: Shutterstock

Technical Writer