It’s fair to say that programmable logic controllers (PLCs) are the brains of industrial systems — capable of controlling a wide variety of other functions akin to the various aspects of the human body. Capable of receiving and transmitting electronic signals, today’s PLCs are capable of watching and governing most mechanical/electrical systems you’ll find across industrial facilities today.
Of course, exactly how a PLC functions depend on how it’s programmed by the user. Based on this, PLCs will respond in different ways to the input information it receives. Examples of input devices include pressure/temperature switches and various sensors that tell the PLC about the real-time conditions in the facility. Based upon these inputs, PLCs output signals to control motors, pumps, fans, valves, alarms and the like.
Let’s take a closer look at four uses for programmable logic controllers in industrial settings.
1: Controlling Material Ratios
There are many instances in which PLCs actually control how products are made during the manufacturing stage of the process. PLC Technician Training offers up two prime examples: cement manufacturing and glass production.
In cement manufacturing, a PLC program can make sure the right quantity and quality of raw materials make it into the kiln — making the final product as cost-effective yet high-quality as can be.
In the production of glass, PLCs can also control the ratio of materials. Furthermore, PLCs can work in tandem with a distributed control network to collect even more data about the various steps in the production process. Gathering a thorough understanding of every process — from start to finish — is the first step toward optimizing them.
2: Automating Smart Factories
The rise of “smart factories” is thanks in part to the capabilities of PLCs in automating various functions. According to the World Economic Forum, smart factories entail physical infrastructure “powered by information and communications technologies, which draw insights from the data in the landscape.”
Rather than requiring humans to oversee every process, PLCs use the insights they receive to execute various commands. The World Economic Forum cites a seafood processing factory in Norway as a prime example — machines evaluate salmon quality, weigh the product, grade the fish and distribute it to production units accordingly.
3: Monitoring & Controlling Environmental Conditions
It’s advantageous for industrial facilities to have the ability to observe conditions and optimize resources as needed — such as monitoring the quality of air, water, and products based on inputs from sensors located around the factory. PLCs can take input measurements from sensors and respond accordingly to adjust the environment as needed.
Food Engineering Magazine outlines an example of a PLC-based system helping a microbrewer maintain a temperature ideal for fermentation. While it would have been possible to install individual temperature controllers on each of seven tanks, it was far more efficient and cost-effective to use a PLC. In addition to being scalable up to 16 tanks, it was easier to view and control them remotely. The PLC monitors the temperature and uses a complex system of valves and cooling zones to constantly optimize the temperature.
4: Optimizes Mechanical Actions in Assembly Lines & Plants
The faster, more accurate and more continuous mechanical actions are in an industrial setting, the more efficient production becomes. PLCs can fine-tune them precisely — such as detecting the exact position of a bottle and filling it to the optimal level with the correct liquid in a beverage plant. PLCs can ensure there exists the proper amount of time between mechanical actions — no more, no less.
While these examples represent four uses for programmable logic controllers in industrial settings, the potential is limited only by what you can imagine.