Last updated on Sep 6, 2024

What are the latest trends and developments in ladder logic programming and PLC technology?

Ladder logic programming and PLC technology are essential skills for electrical control engineers and technicians. They allow you to design, implement, and troubleshoot complex industrial automation systems using graphical symbols and logic expressions. But how do you keep up with the latest trends and developments in this dynamic field? In this article, we will explore some of the most recent innovations and best practices in ladder logic programming and PLC technology, and how they can benefit your projects and career.

1 Structured text

One of the latest trends in ladder logic programming is the use of structured text, a high-level programming language that resembles C or Pascal. Structured text offers more flexibility, readability, and functionality than traditional ladder logic, especially for complex calculations, data manipulation, and modular programming. You can use structured text to create custom functions, data types, and libraries, and integrate them with ladder logic blocks. Structured text is also compatible with most PLC platforms and standards, such as IEC 61131-3 and OPC UA.

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Don Fitchett 🔷

Industrial Training Instructor - Distance learning at BIN95.com (All industrial training topics covered). PLC Training at your location too.
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Structured Text programming (ST) is an excellent example; just because it is a trend/popular, it does not necessarily mean it is the best practice. Like Softlogic was once trending, the industry eventually learned it was not the best practice and returned to Ladder Logic programming. The best practices for the process and manufacturing industry will always return to a primary focus on reliability and reduced downtime costs. ST is easier for programmers to work with during the first automation design year. However, it is more complex and costly for their customers, the final end-user, to work with for the following ten years. The best practice is to program primarily in ladder logic and use ST for data manipulation and algorithm parts.

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2 Function blocks

Another trend in ladder logic programming is the use of function blocks, which are graphical representations of reusable code modules that perform specific tasks or operations. Function blocks can simplify your ladder logic programs by reducing the number of instructions, wires, and contacts, and by encapsulating the logic and data of each function. You can use function blocks to create custom components, such as timers, counters, PID controllers, and data converters, or to access predefined libraries of common functions, such as math, logic, communication, and diagnostics.

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Don Fitchett 🔷

Industrial Training Instructor - Distance learning at BIN95.com (All industrial training topics covered). PLC Training at your location too.
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Function Block programming is not so much a trend as Structured Text (ST) Programming is. But if it were, many reasons for refraining from ST programming would also apply to Function Block (FB) programming. For a programmer, modular programming (Reusable blocks of code) is always a best practice. Each function may also have ladder logic or Structured Text hidden within the function. The end user (plant maintenance and engineering) typically deals with the function block, not the internal code. While FB programming is a graphical programming interface (GUI), making it easier for the automation control end-user to follow, it does have its unique barriers. Difficulty in accessing code within and the methods vary between PLC vendors.

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3 Simulation and testing

A key development in PLC technology is the use of simulation and testing tools, which allow you to verify and debug your ladder logic programs and PLC systems before deploying them to the field. Simulation and testing tools can help you to identify and correct errors, optimize performance, and ensure safety and reliability. You can use simulation and testing tools to emulate the input and output signals, monitor the status and values of variables and registers, and generate reports and logs. Some simulation and testing tools also support online editing and debugging, which enable you to modify and update your ladder logic programs while the PLC is running.

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4 Networking and communication

Another development in PLC technology is the use of networking and communication protocols, which enable you to connect your PLC systems with other devices, such as sensors, actuators, HMI panels, SCADA systems, and cloud services. Networking and communication protocols can enhance your PLC systems by enabling data exchange, remote control, and integration with other systems. You can use networking and communication protocols to implement various architectures, such as point-to-point, bus, ring, star, or mesh, and to support different standards, such as Ethernet, Modbus, Profibus, CANopen, or MQTT.

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Don Fitchett 🔷

Industrial Training Instructor - Distance learning at BIN95.com (All industrial training topics covered). PLC Training at your location too.
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PLC networking and communication's most significant trend is towards ethernet networks. Networking PLCs and automation control have provided the industry with powerful capabilities. My advice on this one is to remember that with great power comes great responsibility. Using the standard computer communication protocol Ethernet instead of industrial communication protocols like Modbus, CANopen, etc., makes the industry a more prominent and softer target for cyber attacks. Additionally, using Ethernet often leads the network to find its way to the internet [cloud], which increases risk exponentially! 'Safety First' should also extend to cyber security regarding industrial automation control of dangerous equipment.

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5 Security and encryption

A vital trend in PLC technology is the use of security and encryption features, which protect your PLC systems from unauthorized access, modification, or attack. Security and encryption features can prevent data theft, sabotage, or cyberattacks, which can compromise the safety and functionality of your PLC systems. You can use security and encryption features to implement various measures, such as password protection, user authentication, access control, firewall, VPN, or SSL/TLS.

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6 Artificial intelligence and machine learning

A cutting-edge trend in PLC technology is the use of artificial intelligence and machine learning techniques, which enable your PLC systems to learn from data, adapt to changing conditions, and optimize outcomes. Artificial intelligence and machine learning techniques can improve your PLC systems by enabling predictive maintenance, anomaly detection, quality control, and process optimization. You can use artificial intelligence and machine learning techniques to implement various algorithms, such as neural networks, fuzzy logic, genetic algorithms, or reinforcement learning.

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7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

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Don Fitchett 🔷

Industrial Training Instructor - Distance learning at BIN95.com (All industrial training topics covered). PLC Training at your location too.
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Some reading my replies may think I am bucking the trends. I am just providing some context in my replies by giving an automation control end-user perspective to contrast the programmer's perspective. The takeaway should always be to keep the end-user in mind. What may be a trend with programmers and automation equipment vendors because it makes their job easier may be a challenging outcome for their end-users in the long run. Always strive to see the big picture and think long-term. Not just project completion.

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What are the latest trends and developments in ladder logic programming and PLC technology?

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1 Structured text

2 Function blocks

3 Simulation and testing

4 Networking and communication

5 Security and encryption

6 Artificial intelligence and machine learning

7 Here’s what else to consider

Electrical Controls

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