Latest Energy & Infrastructure Technical Articles

Credited with coining the name ‘PLC’, Allen-Bradley and parent company Rockwell Automation are major players in the…

Credited with coining the name ‘PLC’, Allen-Bradley and parent company Rockwell Automation are major players in the world of control systems. Learn how the hardware platforms have evolved into the familiar modern configurations.

The timer is a fundamental function of ladder logic programming. In this article, we discuss on- and off-delay as well as…

The timer is a fundamental function of ladder logic programming. In this article, we discuss on- and off-delay as well as retentive timers and define the inputs and outputs required to properly use them.

Power supplies tend to get a reputation as one of the most important power considerations of a DC control circuit - but…

Power supplies tend to get a reputation as one of the most important power considerations of a DC control circuit - but we can’t ignore other key players: power filters, converters, and backup power modules.

What if you could control the end position and the speed of a hydraulic actuator accurately with just a simple signal?…

What if you could control the end position and the speed of a hydraulic actuator accurately with just a simple signal? Some systems use simple open/close valves, but others require far more precision.

Even with the most reliable networks, network outages are inevitable for a host of reasons, and managing these outages in…

Even with the most reliable networks, network outages are inevitable for a host of reasons, and managing these outages in VFD systems becomes critically important.

Although the are similarities in operating theory, relays and contactors are used in industrial circuits for different…

Although the are similarities in operating theory, relays and contactors are used in industrial circuits for different specific applications, and should not be used interchangeably.

In honor of May the 4th, Star Wars Day, we compare the sources and applications of the two most common force-delivery…

In honor of May the 4th, Star Wars Day, we compare the sources and applications of the two most common force-delivery systems - mechanical and hydraulic.

In the first article of this series, we investigate Siemens as a major PLC manufacturer, learning about the hardware,…

In the first article of this series, we investigate Siemens as a major PLC manufacturer, learning about the hardware, software, and key applications of each product lineup.

Two common methods exist for driving induction motors with VFDs - linear scalar control, which is often labeled as V/f,…

Two common methods exist for driving induction motors with VFDs - linear scalar control, which is often labeled as V/f, and vector, or field-oriented control, which can be a bit more complex to understand.

Large DC and AC motor drives often provide terminals for installing a braking resistor. What are these resistors, and how…

Large DC and AC motor drives often provide terminals for installing a braking resistor. What are these resistors, and how do they slow down a machine? What hazards and cautions must be considered?

Redundancy and safety are often seen together in industrial safety systems. Safety relays monitor emergency devices to…

Redundancy and safety are often seen together in industrial safety systems. Safety relays monitor emergency devices to switch contacts based on status - but what makes them different from normal relays?

With the increasing appearance of “web-based” HMIs, we investigate these devices, learn how they differ from the…

With the increasing appearance of “web-based” HMIs, we investigate these devices, learn how they differ from the graphical HMIs, and see implications for our modern control system architecture.

AC motors are common throughout industry - easily controlled by VFDs and without the maintenance that comes with DC…

AC motors are common throughout industry - easily controlled by VFDs and without the maintenance that comes with DC brushes. So then, why are DC motors still used in certain applications?

Before digital control systems, responses were fairly slow. Push a button, and a motor contactor engaged. These days, the…

Before digital control systems, responses were fairly slow. Push a button, and a motor contactor engaged. These days, the speed of computers introduces some new challenges but brings solutions as well.

Modbus is a communication protocol stemming from the early days of Modicon PLCs, but is still common today. These two…

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.

Inductive loads, such as solenoids and contactors, can cause arcs and failures back into electromechanical switching…

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.

Moisture inside industrial pneumatic systems is a major cause for concern, and if the air is not filtered or dried…

Moisture inside industrial pneumatic systems is a major cause for concern, and if the air is not filtered or dried properly, it can lead to serious failures.

Failures of I/O systems are a common source of headache for control engineers. Troubleshooting those devices that have…

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.

The fourth pillar of effective statistical process control (SPC) is the use of designed experiments used to learn as much…

The fourth pillar of effective statistical process control (SPC) is the use of designed experiments used to learn as much as possible from a limited number of experiments, yet remain statistically relevant enough to be useful.