What is SCADA and why does it matter for your business?

December 12, 2023

When a manufacturer, a utility or an operator of industrial assets needs to manage its machines and processes, what is the technology it turns to? The answer is supervisory control and data acquisition (SCADA), a 50+ year-old technology that is nearly universal in industrial operations around the world. But with the exception of process engineers, relatively few people know this technology exists. Let’s learn more about the control systems that power the modern world.

SCADA definition.

First popularized in the 1970s, the SCADA acronym originally described systems that provided automated control and data acquisition. Coinciding with the advent of the microprocessor, SCADA systems were designed to take advantage of exponentially-increasing computing power available on-site at the factory or in the field through telecommunications networks.

Core SCADA system functions.

SCADA systems are responsible for two critical tasks – controlling industrial equipment for large operations such as plants or pipelines, and reading measurements from these operations. More specifically, SCADA systems perform the following:

  • Plant and process system monitoring
  • Industrial process and machine control (manual and automated)
  • Data collection and analysis
  • Alarm monitoring and notification
  • Reporting (real-time and historical)

SCADA systems require data to perform all these activities. In some respects, early SCADA systems were the precursors to the modern concept of digitization.

Industries that use SCADA systems.

Today, SCADA systems are nearly universal across all industries. Any industrial process that automatically controls machines or collects data from sensors uses SCADA technology. Modern SCADA systems can be very small or massive.

The industries and applications commonly associated with SCADA include:

  • Manufacturing
  • Power generation, transmission and distribution
  • Refineries
  • Utilities (water, sewer, electricity, gas)
  • Oil and gas pipelines
  • Commercial properties
  • Airports
  • Shipping
SCADA as a tool to optimize performance.

The most important (and perhaps least talked about) benefit of a SCADA system is that it provides a digital platform for engineers, analysts and business leaders to optimize performance. As a general rule, anything that can be digitized can be improved using computer programming and data science techniques to identify underperformance and simulate the effects of changes.

At a minimum, the real-time analytics that SCADA provides should drive improvements. Human beings are naturally good at pattern-matching, and monitoring results in real-time reveals which changes are improving operations and which are impairing them.

Digital replicas also have the advantage of unlimited simulation. The cost of digitally testing a change to a plant process is a small fraction of a real-world equivalent experiment. There are many companies that have developed tools to simplify this process.

SCADA architecture.

At its simplest, SCADA architecture consists of one or more programmable logic controllers (PLCs), a database and one or more human machine interfaces (HMIs) connected to a central controller.

SCADA system diagram

Naturally, each implementation is as unique as the system it controls or monitors and may involve a combination of local and remote communication networks.

At the highest level, PLCs provide connections directly to machines they can control through signals received from the central controller or commands sent through the HMIs. They also connect standalone or machine sensors back to the central controller, which can record readings in the database or display them in real-time through HMI screens. Data read from sensors are often recorded over extended periods, creating a history of the plant; a synonym for this type of system is “data historian”.

How SCADA connects the plant floor to head office

To visualize how a SCADA system connects head-office decisions to the factory floor, we can look at how it fits in the so-called “automation pyramid.”

This diagram shows how a SCADA system connects to the systems that control it as well as the systems it controls, until we reach the edge of our system.

Automation "pyramid"

This five-layer model shows how head-office planning functions, such as inventory management and business planning, pass from the ERP to the manufacturing execution system (MES) where they are translated to production planning and scheduling. These plans are then executed by the SCADA system as instructions, which are passed through PLCs to the machine/sensors. In reverse, sensor data is filtered at the PLC level, where it passes up to local-, plant- and business-wide reports and metrics.

Sensor data is typically aggregated in PLCs and sent back to the central control system for monitoring, reporting, data collection and analysis. Depending on the configuration, this data may also drive automated controls, sending specific instructions to the PLCs and, ultimately, the machines they control.

The bottom-line: a SCADA system is an important transition layer between the head-office and the plant floor.

Modern SCADA systems

Not surprisingly, SCADA systems have evolved significantly in the last half-century. In terms of their hardware, PLCs are completely different (although they still have the same functionality). Sensors are also more sophisticated, consume less power and can even connect wirelessly.

One of the big changes in SCADA architecture has been the transition from local computing (think of PCs connected to a server on an office network) to cloud-based systems. The advantages of cloud-based SCADA systems are numerous, including enhanced reporting capabilities, always up-to-date software and more secure backup.

In terms of design capabilities, most modern SCADA systems provide easy-to-use tools for designing control systems, including drag-and-drop interfaces, SQL-based data storage and access to modern scripting languages like Python for complex routines.

Well organized, cloud-based data historians support connections to modern analytics and reporting tools, which means data analysts and data scientists can perform sophisticated analysis of plant operations. Furthermore, cloud-based tools with well-defined APIs enable easy integration into the MES and ERP layers.

The bottom line – modern SCADA systems enable real-time status and automated control of the entire operation.

SCADA security

We live in a world where security threats can significantly impact your critical infrastructure and services. Many legacy systems deployed on local networks also involve legacy security risks; however, the proliferation of new Internet of Things (IoT) solutions have also made industrial operations attractive targets for cybercriminals. For some, the obvious solution might be to prevent internet access to the plant. But this approach is akin to burying one’s head in the sand and hoping for the best. It also means forgoing many of the benefits of modern industrial automation.

Not the best security strategy, SCADA or otherwise

The right approach to managing SCADA security is to accept that security threats are real, and that your organization’s assets could be targeted. Beyond ensuring a base-level of security, the relative importance of these assets should determine the appropriate level of protection. Naturally, nuclear power plants will require more advanced security solutions and strategies than a family-run candy factory, but the good news is that there is a solid history of IT security providing protection for such a range of assets.

The future of SCADA

In a world where new digital technologies face near-certain obsolescence in a decade, SCADA has enjoyed a remarkably long run. The reasons are numerous, but the key driver is likely that SCADA systems are literally at the nexus of businesses’ head office functions and the physical operations that feed these businesses.

SCADA systems will be with us for a long time, and they are also adapting to an increasingly digital world. Modern capabilities like cloud computing, wireless access, data science and even AI and machine-learning are expanding the power of today’s control systems to allow for tomorrow’s bright future.


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