Discrete and Process Automation

Industrial applications of PLCs

17 March 2023
Basic electrical design of a PLC panel. Source: SolisPLC

A programmable logic controller (PLC) is essentially a microprocessor-based computer without a conventional user interface such as a keyboard, mouse or display. Its primary purpose is to survive in severe factory conditions. It's a special kind of computer hardware built for controlling a wide range of electro-mechanical operations in sensors, actuators, plants and other industrial processes. These systems are packed with useful features including simple programming, sequential control, timers and counters, user-friendly hardware, and dependable controlling commands. PLCs are engineered to function in the most demanding of industrial settings, including those with strong vibrations, high temperatures, high humidity and high electrical noise levels.

Logic controllers are frequently assigned the responsibility of controlling and monitoring a vast array of sensors and actuators. Thus, their broad I/O (input/output) configurations set them apart from standard computer systems. The PLC's versatility as a control-system component extends beyond its original role as a dedicated digital computer. Therefore, it is not surprising that PLCs are also known as industrial PCs. This article discusses some of the major applications of PLC in industries.


Automation process robots

Industrial robots have robust PLC programs built right into the robot controller. This software has industry-wide implications since it allows a handful of robots to function independently of a master PLC. This means a huge savings in money for smaller companies who would have had to invest in a regular PLC integration.

Productivity in industry

The manufacturing process has become considerably more effective because of intelligent automation, the internet of things (IoT), cutting-edge robotics and other smart factory initiatives. Despite rapid advances in technology, PLCs continue to play a crucial role in production as the core processor for all real-time decisions. For instance, when integrated with cloud computing, the dependable data provided by PLC, such as sensor performance and similar information, may provide a more complete picture, or "big data." More efficient manufacturing processes can be developed with the help of analysis tools used by plant managers and others to better leverage resources, logistics, supplier timing, and batch schedule jobs.

The paper and steel industry

A PLC's purpose in the paper industry is to rapidly automate procedures for maximum productivity. The production of book or newspaper pages is managed and supervised by a PLC. In the steel industry, controlling the boiler's temperature and pressure, the electrode lift, the oxygen lance for steel, the cooling bed temperature, and so on, all rely largely on PLC.

Machine tool monitoring and automobile automation

A PLC is a machine tool that can evaluate inputs and outputs and take actions based on instructions stored in its memory. Using PLCs allows for increased productivity while decreasing the need for human decision-making. In automobile automation industry, in order to standardize manufacturing and boost return on investment (ROI), they employ PLC in automated procedures for automobiles.

Glass industry

Automatic process control systems are used in the glass industry for regulating the proportion of materials and processing flat glasses. The need for PLC control mode in the glass sector has been steadily increasing as this technology has progressed over the years. For instance, the production of glass bottles is one of the most significant areas where PLC is used. The PLC-based spray coating system for glass bottles is an integral feature of the glass bottle production sector.

Food processing industry

Flow rates in main areas of the water treatment plant, as well as valves that regulate in-process water flow, may all be adjusted from afar thanks to PLC used in the food processing system. Moreover, PLC programming may be used to manage and automate the packaging process, which would ultimately result in the packing system becoming totally automated. This would further increase product rate and reduce product time.

It is standard practice for an automated mixing and bottle filling system to begin by combining water and protein solutions from separate containers. Individual bottles will then be filled with the mixed solution. Pressing the system's start button sets everything in motion. In this case, the sensor output is sent into the PLC, whose outputs operate the mixer, valves and conveyor belt.

[Learn more about PLC technology and discover PLC system suppliers on GlobalSpec.com]

Cement manufacturing industry

Cement is made by combining a number of different raw ingredients in a kiln. These constituents, and the ratio in which they are used, affect the final product's quality. All raw materials used must be of the highest quality, hence it is imperative that data be accurate. Operating in user mode, PLC is one component of a distributed control systems being used in the cement manufacturing industry alongside configuration software used in administration and production. PLCs regulate the processes of operating the coal kilns, ball mills and shaft kilns.


A PLC is a specialized piece of computing hardware designed to manage various electro-mechanical tasks in sensors, actuators, sensors, plants and other industrial processes. In today's competitive business climate, effective automation and process control are crucial. Profitability of manufacturing operations is increased by automation projects based on PLC. In addition to speeding up setup, PLCs are capable of simplifying even the most laborious tasks.

To contact the author of this article, email GlobalSpecEditors@globalspec.com

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