January 9, 2019
Most people are keenly aware that modern manufacturing and industrial activities require at least some automation. The term PLC (Programmable Logic Controllers, devices responsible for the modern industrial age) has become increasingly common over the years. However, a few people outside the industry have likely heard the acronym SCADA (Supervisory Control And Data Acquisition). As much as we can all appreciate what the advent of the PLC has done for automation, the development and implementation of SCADA systems have done a great deal to refine modern manufacturing and industrial processes.
Here’s an overview of how these systems work in an industrial setting.
What does a SCADA system do?
In simple terms, a SCADA system is a collection of software and hardware components that allow manufacturers to perform a series of specific functions. These functions include:
- Monitoring and gathering process data (in real time)
- Interacting with field devices and control stations like sensors and motors via an HMI (Human Machine Interface) display
- Recording system events in a log file
- Controlling manufacturing processes locally, or from an off-site location
It’s easy to see how the monitoring and gathering of information (along with the other functions) of an industrial process is crucial in a system that relies heavily on automation. The information that is gathered is analyzed in order to identify opportunities for improved efficiency and to expedite the communication of issues within the system to reduce the amount of time required to repair key pieces of machinery.
Their Design: System Architecture
Typically, SCADA systems are centralized systems that provide monitoring and control functionality for a specific area (up to and including the entire manufacturing process). The simplest way to conceptualize the architecture of a SCADA system is to envision a software package that works hand in hand with the devices on the factory floor.
Sensors and manual operator-activated inputs are positioned throughout the system. These gather data and transmit it to the PLCs. The PLCs in turn transmit that data to the HMI via a wired or wireless network, where it can be viewed graphically and analyzed by an operator situated in the control room. Depending on the system, devices can also be controlled via the HMI workstation. Of course, this is a very simplified explanation of SCADA architecture, but should provide the general idea.
Data Processing and Analysis
As mentioned above, the HMI processes data and makes it viewable for PLC technicians, allowing them to visually locate problem areas within given system. The SCADA system is designed to interpret the data that is gathered and transmitted and send operational commands to the different field devices as warranted to maintain efficiency throughout the process. As one can imagine, constant communication between the HMI, the PLCs, and the field devices is integral to the efficacy of a SCADA system.
Human Machine Interfaces
A system’s HMI is the visual port of entry into the operation of real-time processes. The HMI provides a graphical representation of many of the system’s components, allowing the human operator to take operational control of a piece of equipment from the control room (e.g. in the event of a conveyor jam, the operator can manually shut down upstream and downstream conveyor segments to isolate the jam and make clearing the jam a safer task).
Equipment status is also easy to monitor for each component of a process as these tend to be color coded; alarm notifications are typically configurable. Available controls via the HMI can vary by system, but typical controls include being able to override a piece of equipment or placing it in an out of service state.
Who Uses SCADA Systems?
The sheer number of applications for SCADA systems is staggering. If a manufacturer relies on automated processes, no matter the size or complexity, chances are you’ll find a SCADA system in use. In fact, it wouldn’t be hyperbole to say that many of the world’s most necessary industries would not fair as well as they currently do, if not for SCADA. These industries include:
- Waste Management and Recycling
- Oil and Gas Production
Industrial Automation is Booming
Even those with a cursory interest in manufacturing or automation know that automation and robotics are the future of industrial production. With that said, it is only logical to assume that growth of popularity of SCADA systems will continue to increase at a commensurate level. Naturally, manufacturers will continue to employ SCADA systems to enhance and improve their respective processes.