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How-To: Building a PLC Project with Modbus Communication

How-To: Building a PLC Project with Modbus Communication

Modbus is a communication protocol stemming from the early days of Modicon PLCs, but is still common today. These two example implementations of Modbus transactions will get you started.


Info Byte: Preventing Relay Burnout with Flyback Diodes

Info Byte: Preventing Relay Burnout with Flyback Diodes

Inductive loads, such as solenoids and contactors, can cause arcs and failures back into electromechanical switching devices, causing costly downtime. The solution is cheaper than you think.


Troubleshooting for PLC Modules and I/O Devices

Troubleshooting for PLC Modules and I/O Devices

Failures of I/O systems are a common source of headache for control engineers. Troubleshooting those devices that have polarized connections (source vs sink, and NPN vs PNP) is a technique worth refining.


Understanding the Basics of Pulse Width Modulation (PWM)

Understanding the Basics of Pulse Width Modulation (PWM)

Power delivered to devices can be changed by raising or lowering the voltage and current. But this method does not always produce intended results. Pulse width modulation (or PWM) can be used to better control variable loads.


What Is a PLC? An Introduction to Programmable Logic Controllers

What Is a PLC? An Introduction to Programmable Logic Controllers

What is a PLC? This article will lay out a succinct definition of a programmable logic controller and explain its basic components.


The Origin Story of the PLC

The Origin Story of the PLC

In the late 1960s, a revolution in manufacturing became a reality when the first Programmable Logic Controller (PLC) was developed. We’ll examine the early history of the PLC - not just the technology, but also the inspiration of the inventors as well.


Differences and Relationship Between IT and OT in Industrial Facilities

Differences and Relationship Between IT and OT in Industrial Facilities

We’re all familiar with information technology, or IT. The computer systems, hardware, internet, and various software we use in our own homes and offices are mostly IT. But when it comes to industrial workplaces, the rules are different.


Sinking vs. Sourcing for Control System Modules - Explained

Sinking vs. Sourcing for Control System Modules - Explained

Digital control systems are particular about the direction of current flow from sensors and input devices. The terms sourcing and sinking (often abbreviated source and sink) are among the more confusing ratings found on I/O module datasheets. Part 1 of a 3-part series.


Info Byte: What’s the Reason Behind Relay Terminal Numbering?

Info Byte: What’s the Reason Behind Relay Terminal Numbering?

Any industrial electrician can instantly recognize a relay, but when it comes to wiring, why are the terminals numbered in such apparently random order?


Introduction to Allen-Bradley Data Highway (DH) Networks

Introduction to Allen-Bradley Data Highway (DH) Networks

In this article, learn the basics of Allen-Bradley Data Highway, the various network structures, and the relationship between DH and Ethernet networks.


Lock-out-tag-out (LOTO) Devices for Industrial Safety

Lock-out-tag-out (LOTO) Devices for Industrial Safety

One of the most visible elements of industrial safety is the use of lock-out-tag-out (LOTO) devices, familiar to those with experience. But, if you are new to the workforce, a brief introduction may be helpful.


An Overview of Laser Sensing

An Overview of Laser Sensing

What is laser sensing, how does it work, and what types of laser sensors exist?


Introduction to Industrial Network Gateways

Introduction to Industrial Network Gateways

This article teaches the basics of gateways in industrial networks and PLC-to-PLC communication.


Connecting Multiple PLCs to an HMI

Connecting Multiple PLCs to an HMI

Learn the basics of connecting multiple PLCs to an HMI using various data types.


Process Noise Sources and How to Fix Them

Process Noise Sources and How to Fix Them

Noise signal sources occur primarily from radiofrequency interference (RFI), often in the form of impulse functions or arcing. How do you mitigate process noise from your control system?


Boolean Logic for Ladder Diagrams

Boolean Logic for Ladder Diagrams

Ladder diagrams, or ladder logic, is a popular programming language used for PLCs. Programmers can utilize boolean logic as a base for their ladder diagrams. Learn the basics and structures for boolean logic.


An Overview of AVEVA Solutions

An Overview of AVEVA Solutions

AVEVA Solutions, formerly Wonderware, is a popular service that offers HMI, SCADA, and MES. How is each solution used in industrial automation?


Alternative Devices for Measuring Fluid Volume

Alternative Devices for Measuring Fluid Volume

Flow totalizers, flow sensors, and flow meters are popular devices for measuring flow. However, this article discusses alternative methods, such as ultrasonic level detection and resistive tape.


Introduction to Smart Sensors

Introduction to Smart Sensors

Smart sensors differ from traditional sensors in that they offer benefits such as self-diagnostics, simplified wiring and communication, and more efficient remote monitoring.


How to Utilize Real-time Production Data and Achieve Better Manufacturing Results

How to Utilize Real-time Production Data and Achieve Better Manufacturing Results

Struggling to find the best ways to utilize real-time production data? This article reviews six steps to achieve better manufacturing results.