What is a Safety PLC?

This article investigates the basic qualities that make up a safety PLC, what distinguishes a safety PLC from a standard model, and the reasons for which a safety PLC may be critical. Programmable logic controllers, or PLCs, are a very common type of controller used in automation. They are the baseline of many different automated … Read more

How-To: BRX PLC Programming With Digital I/O

Learn how to use an AutomationDirect BRX PLC with the Do-more Designer software. This tutorial will cover discrete I/O commands along with basic timing and counting ladder functions. These days, it’s not always accurate to assume that a bigger computer means that’s always better. The same is true for PLCs. As electronics technology has improved, … Read more

Alternative PLC Programming Languages

For most systems, there are various languages meant for specific purposes, including Function Block, Sequential Charts, and Structured Text. By far, the most common programming language for PLCs consists of rungs of if-then logic, similar to an electrical line diagram, going by the name of ‘Ladder Logic.’ Many programmers have quite likely been exposed only … Read more

Understanding PLC Program Commands: One-Shots

Many PLC commands are well-known to programmers, including contacts, coils, timers, and counters. But a less-common instruction is the one-shot, capable of harnessing the incredible processing speeds in a CPU. One-Shot Functions In a previous article, I wrote about how to use timers in ladder logic. A typical next step is to discuss counters, being … Read more

What Is the Difference Between Profibus and Profinet?

An overview of the requirements, standards, applications, and main differences between Profinet and Profibus communication protocol, connectors, and evolution from its original technology. Profibus and Profinet are two of the most popular communication protocols used in industrial automation. Both protocols share a similar origin story, as they were conceived out of the need for standardizing … Read more

Siemens SIMATIC PLCs – Hardware History

In this first of an upcoming series, we investigate Siemens as a major PLC manufacturer, learning about the hardware, software, and key applications of each product lineup. Siemens AG is the largest energy and industrial manufacturing company in Europe, and with more than 170 years of history, it is also an innovator in many fields. … Read more

An Overview of Software Languages for Programmable Logic Controllers (PLCs)

What software languages are used with programmable logic controllers? What software languages are used with programmable logic controllers? An important part of using programmable logic controllers (PLCs) IEC 61131-3 is part three of the international standard for programmable logic controllers. In this section of the standard, the software architecture and valid programming languages of a … Read more

Introduction to Modbus

This article will introduce Modbus, an industrial protocol that laid the foundation for fieldbus communication in industrial systems. In 1979, Modicon introduced an application layer protocol (layer 7 of the OSI model) for use with its Programmable Logic Controllers (PLC). This protocol was called Modbus and became the first widely used fieldbus in the history … Read more

Introduction to Mitsubishi PLC – FX Series and MELSOFT GX Developer

Mitsubishi’s FX series PLC is one of MELSOFT GX Developer’s most popular automation solutions for small and medium-scale applications. Learn how to use GX Developer software to program the FX series PLC. The FX series PLC is one of the introductory MELSEC product lines from Mitsubishi Electric. The company is widely recognized for the manufacturing … Read more

Ladder Logic in Programmable Logic Controllers (PLCs)

This article describes the programming language ladder logic used to program PLCs and shows examples of how it functions. Ladder diagram, better known as ladder logic, is a programming language used to program PLCs (programmable logic controllers). This article will briefly describe what ladder logic is and go over some examples of how it functions. … Read more