Programmable Logic Controllers (PLCs) have been one of the cornerstones of automation since they led Industry 3.0 more than 50 years ago PLCs are industrial computers used to control a variety of electromechanical processes in manufacturing facilities and automated environments. Because they are easy to operate and program, PLCs often play an important role in SCADA systems, serving as the physical interface between shop floor equipment and HMIs, as well as communicating, monitoring, and controlling automated processes.
From food and beverage production to water utilities to manufacturing, PLCs are an integral part of virtually every area of modern automation. Using real-time programming, PLCs are able to capture input data from machines on the factory floor and apply user-created program logic in response, generating output data or commands to run various applications and tools such as SQL databases.
You can't have IIoT without PLCs!
As organizations continue to digitally transform through the implementation of Industry 4.0 technologies, the approach to leveraging PLCs has similarly advanced. In modern SCADA systems, data is the focal point, but the traditional poll-response approach to collecting data from PLCs is not always sufficient. In more complex or decentralized systems, PLCs are still the cornerstone, but they can support very different architectures.
Technologies that support the Industrial Internet of Things (IIoT) offer organizations a new level of interoperability. Modern PLCs are an integral part of these IIoT networks, and many of the recent advances revolve around onboard implementations of IIoT-enabled technologies, allowing devices to play a more active role in the overall system architecture. Contrary to the outdated notion that PLCs are only useful for basic I/O, newer models have a wide range of communication capabilities, including cloud connectivity and edge computing, making them powerful tools both on the factory floor and in remote locations.
PLC powering the edge
Especially in industries such as oil and gas, collecting data at the edge of the network can be difficult due to harsh environments or lack of infrastructure. Edge computing endeavors to overcome these difficulties by moving PLC polling closer to the source, thereby reducing latency and increasing reliability.
Network edge PLCs typically employ IIoT-ready communication protocols such as MQTT, which use a publish-subscribe model to conserve bandwidth while maintaining an open data stream. To avoid network connectivity issues that can lead to massive data loss, MQTT's store-and-forward functionality collects up to seven days of data on the PLC itself and backlogs the information to the server when the network reconnects.
Do more with PLCs
Although vital, PLCs are only one part of a successful data management architecture. To fully unleash the power of your system, you need to connect PLCs to best-of-breed solutions. Not only can you collect and record data from virtually any PLC, but you also have the tools to perform advanced analytics to help your organization make smarter, data-driven decisions.