What is a SCADA System and How Does It Work?

We get asked all the time, “What is a SCADA system and how does it work?” SCADA stands for Supervisory Control and Data Acquisition. It is a type of control system designed to collect data from industrial equipment.  In this article, we’ll provide you with a high-level introduction to SCADA systems, how they work, and how to get started.

If you’d prefer to learn about SCADA through a short video, check out our Tech Edge video below.

What is a SCADA system?

A SCADA system is a combination of hardware and software that enables the  automation of industrial processes by capturing Operational Technology (OT) real-time data. SCADA connects the sensors that monitor equipment like motors, pumps, and valves to an onsite or remote server. 

 A SCADA system empowers organizations to:

• Control processes locally or at remote locations
• Acquire, analyze and display real-time data
• Directly interact with industrial equipment such as sensors, valves, pumps, and motors 
• Record and archive events for future reference or report creation.

To learn more about SCADA, download our eBook – The Ultimate Guide to Supervisory Control and Data Acquisition

SCADA system hardware

Hardware such as Remote Terminal Units (RTUs) and Programmable Logic Controllers (PLCs) serve as local collection points for acquiring sensor information. This hardware in a modern SCADA system will often trigger actions of the connected piece of equipment via programmed logic. In a SCADA system, the collected data from the sensors is gathered by a computer commonly known as a “gateway.”

Different edge workloads use computer hardware in various ways.

• Gateways pass the data from PLCs to servers or to the edge.
• Edge computers are close to the source of the data and can act as a gateway. However, they will first process the data before transferring to the cloud or central physical server. This enables quicker decisions at a local level as well as bandwidth and cost savings.
• Human Machine Interfaces (HMIs) provide a local touchscreen interface for machine monitoring and control. They can also act as gateways or edge computers. 
• The server itself acts as the central control for your local SCADA system. Your local historian server (historical data logging over time) may live here. Depending on the architecture it may also report back to cloud or a larger server on the enterprise network

Once collected, sensor data can either be acted upon directly through the use of SCADA software, or saved for later review. SCADA systems can help monitor and control processes from the same location in which actions are performed, or from a remote site.  

Programmable logic controller in industry.

How does SCADA work?

One of the major efficiencies of SCADA is the ability to monitor and control systems in your facility from multiple locations – even remote locations. Depending on the configuration of the SCADA control system, the state of the production processes can be viewed from an operator workstation overlooking the industrial plant, a HMI located directly beside machinery, or even from the home of an employee.

You can also influence and control a SCADA environment without having to directly respond to each event. Using logic-based rules, operators are able to designate the completion of certain actions when sensors detect abnormalities. For example, is the rotating bit on a plywood cutting machine vibrating excessively? The SCADA software can be programmed to power down the machine immediately and avoid causing further potential harm to materials or operators.

Facilities often choose a hybrid version of direct and automated control by creating rules that alert an operator to the abnormal operation. The operator can then make an informed decision on the appropriate next steps.

Who uses SCADA?

By providing real-time visibility over the state of assets and operations, SCADA helps business owners and operators make smarter decisions, improve efficiency, and minimize downtime. A huge range of industries use SCADA including manufacturing facilities, oil and gas operations, and public utilities. 

Examples of a SCADA system

Smart City

From wastewater treatment to power grid management, smart cities are increasingly relying on SCADA control systems to help monitor and optimize everything from traffic light patterns to public power consumption. When a city is able to see spikes in resource usage, such as public transit or electrical consumption, they are able to more quickly respond.

Cities can optimize resources over the long term when repeated trends are recognized. For example, certain temperatures and humidity levels may directly correlate with residents turning on their heating or cooling systems. City managers can prepare the grid to increase electrical production and transfer as those conditions develop. 

At a more granular level, the increasing number of electric vehicles being charged is likely to have a growing impact on city electric grids. SCADA systems are one way to help monitor and adjust to evolving demands for power such as this.

Smart Manufacturing

Modern factories monitor data from machinery sensors in order to predict maintenance, monitor output speed, and increase operator safety. For example, a piece of equipment may become less efficient at a certain point in its maintenance cycle. With a SCADA system, you could recognize this pattern and change the maintenance schedule to avoid a production bottleneck. Without a SCADA system, it would be difficult to recognize such patterns manually.

One example of a SCADA system utilizing Ignition by Inductive Automation

How to implement a SCADA solution

To implement a SCADA solution, we suggest you follow these steps:

• Clearly define and understand what you want to monitor
• Determine what data you currently collect and how 
• Start small: pick one set of data and one location to do a proof of concept (POC)
• Understand what architecture is needed to scale for your needs
• Add gateways to connect current data collection points
• Create new data collection points if desired
• Centralize your data to your intended monitoring location
• Map data in your SCADA software of choice
• Add visualizations of data and controls
• Define automations and rules

SCADA software then takes over to help you interact with your facility, alert you to issues, inform predictive maintenance, and provide control over a handful, or even thousands of pieces of equipment.

It may seem complicated at first, but the goals are simple. First, connect the things you want to monitor.  Then, select the location from which you wish to monitor and control them.

Integrated SCADA software

With the amount of data being produced in modern industrial facilities, the opportunity for optimization has never been greater. The concept of collecting and acting on data isn’t new. But, today’s SCADA solutions offer incredible insights and capabilities that were previously inaccessible.

OnLogic partners with the SCADA experts at Inductive Automation. They created the popular and powerful Ignition SCADA software which was specifically developed to streamline modern industrial automation implementations. Our line of hardware with Ignition Edge software pre-installed can help you get up and running with a SCADA solution more quickly.

If you still have questions about SCADA,  contact our team of experts today. 

This blog was originally posted on December 1st, 2021. We updated the content on September 20th, 2022.