Supervisory control and data acquisition (SCADA) integrates hardware and software control elements to automate industrial processes. SCADA systems collect, process, and categorize critical data about system performance. This data is compiled and displayed for a human operator, allowing for accurate decision-making based on real-time data.
Based on their extremely broad capabilities, SCADA systems may be programmed for virtually any facility size, budget, or industry. This includes large-scale manufacturing and processing plants as well as smaller systems like traffic lights and home monitoring devices. Wherever data requires supervision and action, SCADA can help streamline the process.
When implemented properly, SCADA leads to large-scale improvements in efficiency for processes that require monitoring. In the manufacturing industry, such systems can detect whether productivity targets or quality assurance targets are being met. If there is a discrepancy in one of these measures, the operator receives information on the nature and location of the error, allowing for prompt action. Some systems can even perform basic tasks without human intervention when certain thresholds are met, allowing for emergency shut-offs or similar limited actions.
It's important to note that SCADA does not replace industrial control systems, and a SCADA system cannot typically control a plant on its own. Instead, SCADA is a solution for centralizing data from widespread industrial components, allowing for more informed decision making. At Turner Integrated Systems, we treat SCADA programming as a part of your larger industrial control system, providing comprehensive control panel and operator interface designs to facilitate automation on all levels.
SCADA System Components
SCADA systems draw on a set of five distinct component types that, when combined, allow for wide-reaching, highly-specialized applications. These pieces work in tandem with sensors to smoothly automate industrial processes.
- Remote Terminal Units (RTUs). Remote terminal (or telemetry) units are one of the basic ways that SCADA software can interface with physical system components. RTUs function primarily to monitor sensors and actuators to transmit their data points to the central control unit.
- Programmable Logic Controllers (PLCs). PLC function overlaps quite heavily with that of RTUs. Both are microcomputers capable of reading, translating, and transmitting measurements. However, PLCs tend to be favored in local field environments as they are economical and capable of high transmission speeds at short distances. RTUs, on the other hand, might be preferred when the system is more geographically dispersed. It's not crucial to understand the fine distinctions between RTUs and PLCs when first considering a SCADA system. In many cases, they are interchangeable.
- Supervisory Computers. Supervisory computers are the control center of a SCADA system. They collect information from the RTUs and PLCs and also transmit commands in the other direction, allowing for remote control of system components. There might be multiple supervisory computers at each operator control interface.
- Human Machine Interface (HMI). Generated by the supervisory computer, the HMI is a graphical interface that displays data in a useful way for the human technician. By monitoring and interacting with the HMI, an employee can view trends or schematics, perform diagnostics, and alter system variables according to new information.
- Communication Infrastructure. The communication infrastructure forms the framework on which all of the other components communicate.
As important as it is to understand distinct components, it's impossible to fully understand SCADA programming by viewing the parts in isolation. System architecture extends the view of SCADA, describing the way that the components interact with one another to form an integrated control network.
The data processed by SCADA software comes from automated sensors or, less commonly, manual measurements. These data points include measurements such as temperature, pressure, voltage, or other key variables. After each recording, an RTU or PLC transmits the new information to the supervisory computer. This information transfer allows the supervising computer to display it graphically on the HMI so that the operator can regulate key decisions.
In some cases, the RTU or PLC itself can be programmed to take simple control actions based on the result of a measurement. More often, the supervisory computer or human operator must issue a command to alter the system's state.
In practice, SCADA architecture can get quite complicated, encompassing hundreds or thousands of different components and a variety of communication protocols. This overall flow of information and commands, however, holds true for most networks.
It is a common misconception that SCADA is the same thing as a Distributed Control System (DCS). Although there is some overlap given that DCS also supervising industrial processes, the overall setup of the systems differs.
- In a DCS system, the emphasis is on computer regulation of local processes. An operator can intervene in the system, but human analysis and intervention is not the primary goal of a DCS system.
- By contrast, SCADA systems aim primarily to compile data in a way that is useful for an operator to make routine or emergency decisions about system functioning.
These different goals also manifest in different programming techniques. A DCS typically relies more heavily on simple logic gates to form control loops. SCADA programming involves more complexity, but that also makes it more flexible. Logic gates might still play a role at the RTU and PLC level, but SCADA programming requires the use of specialized industry software or custom software to manage and display incoming data.
When custom software is used, it is typically designed in C or a similar programming language. Once this advanced development is delivered to a client, the only programming that remains is to configure variables for the RTUs, PLCs, and HMI using graphical interfaces. In doing so, an operator can name and view variables or configure schematics and diagrams without necessarily writing code.
At Turner Integrated Systems, we handle all SCADA programming and interface design. We'll analyze your facility's needs to develop a comprehensive custom interface that performs exactly the functions you need.
SCADA Security With Turner
A final SCADA consideration that should be taken seriously is cybersecurity. Initially, SCADA systems relied on additional human interactions to check sensors and manage control points. Now, many of these tasks have been automated using internet protocols, which drastically increases efficiency at the expense of increased vulnerability to cyber-attacks. These attacks might come in the form of hacking or malware designed to disrupt functionality.
To protect against these risks, Turner's system architects follow security best practices at every stage of the development process. We also provide rigorous documentation, in-house programming, and on-site installation, preventing any possibility of third-party interference and empowering clients to monitor against intrusion.
Where SCADA is Used
A number of diverse industries rely on SCADA programs to streamline their day-to-day operations. These include:
- Manufacturing: Quality control, inventory management
- Traffic control: Traffic signal regulation, mass transit power distribution and tracking
- Water and sewage treatment: Flow monitoring and regulation, automated cleaning cycles
- Energy generation and distribution: Voltage monitoring and regulation, circuit breaker management, power grid management
At Turner Integrated Systems, we draw on experience from across industries to develop personalized turnkey industrial control systems. Our senior engineers work closely with your decision-makers from day one, striving to understand your needs while keeping you informed of the most effective, economical solutions.
Throughout the process, we'll maintain control of design and manufacturing in-house, preventing security vulnerabilities and providing you the peace of mind that comes with consistency and expertise. When your system is ready, we'll provide full installation and documentation services, including information about updates as they come.
To see examples of Turner's expert SCADA programming and industrial control system design offerings, we invite you to review our portfolio, which best illustrates our capabilities. If you're ready to learn more, you can reach out directly so we can show you what such a solution would look like for you.