Allen Bradley’s Data Highway Plus (DH+) networking ability is still found commonly in interfaces with legacy equipment. Understanding this network structure…
Allen Bradley’s Data Highway Plus (DH+) networking ability is still found commonly in interfaces with legacy equipment. Understanding this network structure can bridge the gap between old and new systems.
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.
Hysteresis is a term introduced in basic control system courses and listed on sensor datasheets, but the terms is not…
Hysteresis is a term introduced in basic control system courses and listed on sensor datasheets, but the terms is not often understood, with error deriving from both the system itself as well as the sensor.
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?
Advanced features such as programmable limits, diagnostics, and remote configuration are available with IO-Link devices.…
Advanced features such as programmable limits, diagnostics, and remote configuration are available with IO-Link devices. Learn how to connect an example IO-Link block into an actual PLC project.
Linear position sensors are used in electrical and fluid-actuated motion devices. They allow extremely precise position,…
Linear position sensors are used in electrical and fluid-actuated motion devices. They allow extremely precise position, velocity, and acceleration control, and provide feedback to ensure product quality and tolerance compliance.
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.
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.
Power delivered to devices can be changed by raising or lowering the voltage and current. But this method does not always…
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.
Analog and digital multimeters have both enjoyed popularity in different generations of electrical systems. What is…
Analog and digital multimeters have both enjoyed popularity in different generations of electrical systems. What is unique about the analog meters, and in what situations might they be preferred over their digital counterparts?
Statistical process control (SPC) allows for continual improvement process (CIP), a method of optimizing a process driven…
Statistical process control (SPC) allows for continual improvement process (CIP), a method of optimizing a process driven by data and statistical methods.