Whether you work in manufacturing, traffic control, automotive, or another industry where machinery and automated equipment reign supreme, it’s likely you’re familiar with programmable logic controllers or PLCs.

These intelligent devices are critical for the smooth operation of automated machinery-but how exactly do they work, and how can you use one correctly? Industrial parts can be extremely complex. Find out in this article.

What is a programmable logic controller?

Programmable logic controllers are a type of computer designed to control the automation of industrial processes. The name programmable logic controller stems from the device’s ability to execute complex logical sequences of programmed instructions.

PLCs are popular within manufacturing and other industrial settings for controlling machinery and equipment such as conveyors, cranes, and ovens. You’ll also find them in civil applications such as controlling traffic lights and elevators.

It is worth noting that integrated circuit programming tends to be a crucial element of PLCs. It can ensure that the microcontrollers and electronic components within the PLC are configured to execute the specific control logic and automation tasks required for industrial processes. This programming grants the PLC the customization, flexibility, and precision necessary to adapt its behaviour to diverse applications, making it an indispensable tool in industrial and civil automation.

That said, it is important not to overlook the electronic component packaging, as it can play a pivotal role in the overall reliability and efficiency of industrial processes. The choice between various packaging methods, such as tape and reel or Digi-Reel services, can significantly impact production line efficiency and the seamless operation of automation systems. Therefore, conducting meticulous research by exploring trusted online sources or referring to industry-specific information, such as ProEx’s post on their tape and reel vs Digi-Reel services can be vital. Ultimately, the right choice can contribute to the seamless operation and reliability of your automation and manufacturing processes.

Basic PLC functions and applications

To function, PLCs follow preprogrammed instructions presented as a sequence of steps, called a program. The program is stored in the PLC’s memory, allowing it to carry out automated operations in a given sequence. PLCs find extensive use in tasks such as monitoring temperature, controlling motors, managing production lines, and handling complex sequences of operations. In the realm of quality control, PLCs integrate seamlessly with specialized equipment like a Line Scan Camera to facilitate real-time inspections of products on assembly lines. This collaborative application ensures that the PLC not only streamlines processes but also enhances the quality and accuracy of production outputs, demonstrating its pivotal role in modern industrial automation.

PLCs also play a vital role across a range of other applications, including:

• Batch processing in the cement, food, paper, and chemical industries,
• Water tank quenching in the aerospace industry,
• Washing machine, elevator, and traffic signal control,
• Burner management systems (i.e. flame safety checks, valve switching for fuel changeover, etc.)
• Screen washing and register control systems in the printing industry,
• Escalator and safety control system operation in the travel industry,
• Many more.

PLCs use several helpful features and functions to perform their duties within these applications, such as timers, counters, and sequential control. Its robust construction allows for reliable control and ease of programming even under harsh industrial conditions.

Using a PLC effectively

To understand how to effectively use a programmable logic controller, you’ll first need to learn about its parts. The three modules a standard PLC comprises are:

• Input/output modules, which connect the actuators and sensors to the PLC, allowing it to detect parameters such as flow, temperature, and pressure,
• Power supply module, which receives AC power and converts it into DC for the other modules to use,
• CPU module, which performs the processing and data computations necessary to run the device.

Programming a PLC typically requires specialised programming software or a programming device. You can write instructions in one of five standard programming languages, which are:

• Instruction List,
• Ladder Logic,
• Structured Text,
• Function Block Diagram,
• Sequential Function Chart.

Ladder Logic is the most common language for programming PLCs. In Ladder Logic, programmers use symbols representing shift registers, counters, mathematical applications, and opening and closing relays to tell the PLC what to do. Its visual layout makes it easier to program and read than other languages.

The future of PLCs

With the rise of cloud computing, robotic integration, and intelligent automation, PLCs will continue to play a central role across industries. As technology changes, PLCs must adapt, using artificial intelligence and communication with the Industrial Internet of Things (IIoT) to continue serving businesses around the globe.