A Programmable Logic Controller (PLC) is an industrial computer control system that is used to control manufacturing processes, such as assembly lines, machines, robotic devices, or any activity that requires automation. PLCs are ruggedized and adapted for industrial use, and they can automate a specific process, machine function, or even an entire production line.
PLCs receive information from connected sensors or input devices, process the data, and trigger outputs based on pre-programmed parameters. They have programmable memory used to store program instructions and various functions, and they consist of a processor unit (CPU) which interprets inputs, executes the control program stored in memory, and sends output signals, and a power supply unit which converts AC voltage to DC. PLC programs are typically written in a programming device, which can take the form of a desktop console, special software on a personal computer, or a handheld programming device. Then, the program is downloaded to the PLC directly or over a network, and it is stored either in non-volatile flash memory or battery-backed-up RAM.
PLCs are modular, which means that you can mix and match the types of input and output devices to best suit your application. They are a flexible and robust control solution, adaptable to almost any application. PLCs can monitor and record run-time data such as machine productivity or operating temperature, automatically start and stop processes, generate alarms if a machine malfunctions, and more.
PLCs are different from industrial PCs, microcontrollers, and other industrial control solutions because they have a few key features that set them apart, such as:
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HMI: In order to interact with the PLC in real-time, users need an HMI, or Human Machine Interface. These operator interfaces can be built into the PLC or can be separate devices.
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Proprietary software: It’s common for PLCs to use proprietary software, which can limit the ability to customize or modify the system.
Overall, PLCs are an essential component of industrial automation, and they can greatly enhance almost any production line, machine function, or process.
