The highest caliber of PLC programming is always THE sought-after solution by companies whose existence goes hand-in-hand with facility management. Ensuring that all mechanical operations are working in tandem with each other allows for a more cost-effective, efficient, and highly productive environment.
PLC is an acronym for programmable logic controller. At its core, a PLC is a computer capable of running a blindingly large amount of operations at one time. It serves as a central processing unit in charge of the split-second movement of programmed information being sent to I/O (input/output) modules. As facility management finds it necessary to utilize a fair amount of facility automation, finding the right PLC solution becomes imperative.
As one might deduce, PLC relies on programming language to provide instructions. It is here that there is discourse as to what it the best programming language for use with a PLC. Even within industries, facilities sometimes work off of different languages, which can create confusion.
In general, there are five popular types of PLC programming languages:
- Ladder Logic Diagram
- Structured Text
- Sequential Function Charts
- Function Block Diagram
- Instruction List
While each language has its pros and cons, it is important to have familiarity with each as this may be helpful when trying to ascertain a best use scenario for a particular application. Here is a brief breakdown down of each:
Ladder Logic — This is perhaps the simplest of all the PLC programming languages. It is widely used because of its user friendliness. The name comes from its appearance having a familiar resemblance to relay-based circuit electrical drawings that look like a ladder. Herein lies why ladder logic proves to be a go-to language. Before the use of PLCs, relays were at the heart of early automation. Ladder logic was created to resemble this familiar layout. This made it more intuitive & would not require any extensive amount of training to use.
Structured Text — More advanced functionality comes from this language as it has the capability of being highly complex. Also, it looks quite familiar to coding language like C++ or Java. This makes it much easier to navigate for personnel trained in more traditional programming. What’s more, it has become a standardized language with most PLC-based systems. This allows for an easier transition to use in a facility.
Sequential Function Charts — This approach is ideal for facilities that operate with specific sequences to be followed in a certain order. However, this ends up being a primary disadvantage as it has limited usage in an optimal manner.
Function Block Diagram — Complex functions and sequences are represented in a visually intuitive manner. This language is most often used in places where motion control sequences are found, as well as proportional integral derivative (PID) controllers are employed to reach, and maintain, target points (e.g., temperature). Function block diagram programming is quite flexible & easy to use. That said, this flexibility can allow different programmers to operate the layout in very subjective ways, making for less standardized operation.
Instruction List — This programming language is considered a low-level, which makes it very efficient & use less memory. In many ways, it is ideal for applications where fast processing speeds are required. It is user-friendly, but with one major caveat — analyzing & troubleshooting the language is difficult with training. This is one of the reasons the language was deprecated & thought to be on its way out in terms of utilization.
The Need to Modernize
The ins and outs of PLC programming can be difficult to navigate. However, if a facility wants to operate in a modern fashion, integrating it will be a crucial step toward progress. As such, it is without a doubt that getting input from an automation/technical-savvy firm to find the ideal solution for a specific application will be invaluable.
Connect with our amazing I&E division here at CCI Culberson for your PLC programming needs today.