There are several different methods useful for causing an AC induction…
Regulating the electric power sent to an electric motor is a task…
AC induction motors are based on the principle of a rotating magnetic…
A simple control system drawn in block diagram form looks like this:…
The following animation shows how the “rotating” magnetic…
DC electric motors generate torque by a reaction between two magnetic…
An electric motor is often used as a discrete control element in a…
The key to understanding how three-phase electric motors work is to…
Modern DC and AC motor drives provide features useful when using…
The simplest form of 4-20 mA current loop is the type used to…
Any two electrical conductors separated by an insulating medium…
Area refers to the size of two-dimensional surface. Volume refers to…
A proximity switch is one detecting the proximity (closeness) of some…
Self-balancing pneumatic instrument mechanisms are very similar to…
A fluid is any substance having the ability to flow: to freely change…
As we have seen, the concept of differentiation is finding the…
An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973,…
Virtually any mass above absolute zero temperature emits…
Disturbances in the liquid tend to complicate liquid level…
To calibrate an instrument means to check and adjust (if necessary)…
The final element of PID control is the “D” term, which…
Many liquid substances undergo a process whereby their constituent…
One of the most common, and most useful, pressure measuring…
A pressure switch is one detecting the presence of fluid pressure.…
A laser is a light source emitting waves of light that not only…
In the United States, the ANSI and IEEE organizations have…
In some process applications, it is important that the control valve…
Multiple accessories exist for pressure-sensing devices to function…
The efficient identification and correction of instrument calibration…
Filled-bulb systems exploit the principle of fluid expansion to…
A very common form of on/off valve used for pneumatic and hydraulic…
The most popular form of signal transmission used in modern industrial…
Imagine a liquid-level control system for a vessel, where the position…
Displacer level instruments exploit Archimedes’ Principle to…
Every flow-measuring instrument exploits a physical principle to…
The term “grid” refers to the conductors and equipment…
When a high-energy photon strikes an atom, it may eject one of the…
A powerful mathematical concept useful for analyzing practically any…
Some of the simplest types of digital communication networks found in…
When control valves operate between fully open and fully shut, they…
The advent of “smart” field instruments containing…
A positive displacement flowmeter is a cyclic mechanism built to pass…
Fluid pressure exerts force on any surface area it contacts, as…
A quantitative PID tuning procedure is a step-by-step approach leading…
Since we often use electricity to convey energy from one location to…
Programmable logic controllers are essentially nothing more than…
Atom: the smallest unit of matter that may be isolated by chemical…
The following photograph shows a large air blower in a wastewater…
An electric motor is often used as a discrete control element in a…
