Discrete Manufacturing

Benefits of learning ladder logic for industrial programming

Ladder logic is challenging for industrial programming, but it is a valuable skill for engineers looking to enhance their skill set.

By David Breen July 10, 2020
Courtesy: Breen Machine Automation Services

 

Learning Objectives

  • Ladder logic is a challenging programming language to learn for those not familiar with industrial programming.
  • Users familiar with object-oriented language (OOL) may not be used to the more manual nature of ladder logic.
  • Ladder logic is a product of an industry that has been slow to adapt to the more modern approaches.

I started programming as an early teen, received a bachelor’s degree in computer science and I’ve worked as a software and web developer for over a decade. I’ve been a programmer before attaining the degree: teaching myself, learning new languages and trying new things. Transitioning to industrial programming was the biggest changeup in my history, but also a valuable one.

Adding ladder logic into industrial programming

The first thing when adding ladder logic to industrial programming is it looks like a bad visual integrated development environment (IDE). Like somebody tried to give you a flowchart you could drag and drop onto. Considering it’s mostly a mix of logical gates, it really does behave like that.

Once you start to tinker, get your head around it, it’s usable. Basic structures like loops are a mess, sure, and the variable structure is ugly. The whole program is stuck in an infinite loop. The thing that’s going to slow you down the most is how much you need a mouse.

With object-oriented language (OOL) such as Java, VB, or any common scripting language, navigation requires very infrequent mouse usage. Get to the place you want to edit and start typing. There’s a double-click here and there, but it’s mostly typing because it’s all characters and symbols. To speed things up, many IDEs have an auto-completion function built-in.

Learning ladder logic can be challenging, but it is a valuable skill for those working in industrial programming. Courtesy: Breen Machine Automation Services

Learning ladder logic can be challenging, but it is a valuable skill for those working in industrial programming. Courtesy: Breen Machine Automation Services

Navigation inside PLC programming

In ladder logic, keyboard shortcuts can keep things moving, but navigating between rungs with only the arrow keys can be tedious, slowing down the execution, and derailing your train of thought. Ever walk into a room and forget why you went in there? Imagine that happening every 10 seconds.

OOL and a modern IDE provide autocompletion of variables and method names, easy navigating, better code organization and structure and more effective use of screen real estate. Instead of a bunch of boxes and arrows to space things out, all that appears are letters and numbers. The user can see much more information without having to scroll around.

The biggest hurdle when switching to industrial programming is how slow it is. It’s a beast of its own in a variety of ways, and there’s only so much that can improve speed. Things are going to take longer to write in ladder. It’s a given.

Looking forward: PLC programming needs more PC programmers

As for the other issues, they’re remnants of the early days of an industry that has been slow to adapt. That is exactly why I think the industry needs more PC programmers. The manufacturing industry hasn’t seen significant changes to its programming methodologies in decades despite immense improvements in other fields. It needs fresh ideas and modern concepts.

PLC programming is not fun, not efficient and not easy to maintain. And yet, it remains a very worthwhile skill. Frankly, the more PC people who learn it, the faster we can help the industry evolve its methods to more accessible and maintainable solutions.

David Breen, lead programmer, Breen Machine Automation Services, a CFE Media content partner. This article originally appeared on Breen Machine Automation Services’ blog. Edited by Chris Vavra, associate editor, Control Engineering, CFE Media, cvavra@cfemedia.com.

MORE ANSWERS 

Keywords: PLC programming, ladder logic, object-oriented language

Ladder logic is a challenging programming language to learn for those not familiar with industrial programming.

Users familiar with object-oriented language (OOL) may not be used to the more manual nature of ladder logic.

Ladder logic is a product of an industry that has been slow to adapt to the more modern approaches.

ONLINE 

Read this article online at www.controleng.com for additional stories about ladder logic.

Consider this 

What benefits did you gain from learning ladder logic?


David Breen
Author Bio: David Breen, lead programmer at Breen Machine Automation Services, LLC.