What is PLC Programming?

Over the last few decades, manufacturing industries and plants have been turning to automation to revolutionize industrial activities and practices. Automation in these industries and plants improves work operations and increases production speed while reducing the reliance on manual labor. It helps these industries scale up and grow into billion-dollar industries.

Programmable Logic Controllers (PLCs) are the basis of industrial automation. They can be fully automatic or have buttons and switches that humans can use to control machinery operations. PLC is an automation and control system that receives and processes information from machinery and manufacturing floor operations.

They have controllers that output the processed information, which is used to control the machinery operations. PLCs automate the operations on manufacturing floors by processing input information and releasing control commands based on the reports of the input information.

What Does PLC Programming Entail?

PLCs operate from program instructions that P L C Programmers design. PLC programming is a vital part of designing control applications. It allows PLC to operate effectively either through human input or fully automatic inputs. The control program is designed in either a graphic or textual form and is logic-based to ensure logical solutions to specific real-time industrial applications requirements.

PLC control software can either be designed by the PLC hardware manufacturers or by custom software designers who use the specific manufacturer’s allowed points to introduce and apply their custom code. The installed program runs as software with a Human Machine Interface (HMI), a graphical representation of the program’s variables. The graphically represented variables allow users to read, understand, interpret, and manipulate the code, ultimately controlling the industrial operations of the attached machinery.

What Languages are Used in PLC Programming?

Currently, several PLC equipment manufacturers design and develop industrial automation PLC. Such companies design and develop all types of industrial automation PLC from small equipment to large or high-end ones. Each manufacturer crafts its dedicated programming software for programming and configuring PLC hardware.

Programming languages differ between these manufacturers. Some manufacturers prefer to use common languages such as C and BASIC programming languages for hardware configuration. However, some manufacturers prefer the use of custom languages. For both, the programming languages can be divided into either:

Textual languages:

  • a structured text (ST), or
  • an instructions list (IL)

Graphical language:

  • Function Block Diagram (FBD)
  • Sequential Function Chart (SFC)
  • Ladder Diagrams (LD)

Graphical Programming Languages are the most preferred type between the two. It is due to their simplicity, ease of use, and convenient programming features. Here, all the programming required functions and functional programming units come with the instruction library of the PLC software. That includes the strings, timers, counters, comparators, arithmetic, and numeric functions, calling functions, bit-shift, among others.

What Devices are Used for Programming PLCs?

PLC programming can be done on various devices ranging from handheld devices to PCs; these devices are used for entering, modifying, and troubleshooting code. For handheld programming devices, the device is connected to the PLC using a connective cable. The connective cable allows the user to transfer and edit code into the PLC.

For PC devices, manufacturer-designed software is used to edit, run, and troubleshoot the program in either online or offline states. After the program is fully functional, the programmer uses a programming cable to transfer the program to the PLC.

Final Thoughts

PLC is the basis of industrial automation, and they are designed as hardware by manufacturers, who then allow PLC programmers to enter their custom program code into the device. Programming for this program can be done using a text-based or a graphic-based language.

Cheryl Henson

Cheryl Henson is a passionate blogger and digital marketing professional who loves writing, reading, and sharing blogs on various topics.

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