The vast majority of PID controllers in service today are digital in…
Modern DC and AC motor drives provide features useful when using…
AC induction motors are based on the principle of a rotating magnetic…
To better understand the design and operation of self-balancing…
The simple PLC ladder diagram (LD) commands consist of contacts and…
A limit switch detects the physical motion of an object by direct…
In the United States, the most common language used to program PLCs is…
There are several different methods useful for causing an AC induction…
In order for any PID controller to be practical, it must be able to do…
Phasors are to AC circuit quantities as polarity is to DC circuit…
Negative feedback systems, in general, tend to cause confusion for…
Although it seems each model of PLC has its own idiosyncratic standard…
The simplest form of 4-20 mA current loop is the type used to…
Non-dispersive analysis, while newer in discovery than dispersive…
Perhaps the most basic and necessary protective relay function is…
The reason why a pneumatic control valve’s stem position…
An electric motor is often used as a discrete control element in a…
DC electric motors generate torque by a reaction between two magnetic…
In addition to directly performing logic functions, electromechanical…
Perhaps the most important rule of controller tuning is to know the…
A simple control system drawn in block diagram form looks like this:…
A Safety Instrumented Function, or SIF, is one or more components…
The purpose of a control valve actuator is to provide the motive force…
A limit switch detects the physical motion of an object by direct…
The final step in treating wastewater before releasing it into the…
Perhaps the most confusing aspect of discrete sensors is the…
These fortifications focus on human behavior rather than system design…
A much simpler alternative to continuous vibration sensors…
Shown here is a partial listing of principles applied in the subject…
Coy, John J. et. al. (December 2012) Sampled graphic illustrations…
Any physical location in an industrial facility harboring the…
A bridge circuit is basically a pair of voltage dividers where the…
Developed by the Modicon company (the original manufacturer of the…
Programmable logic controllers are essentially nothing more than…
Every programmable logic controller must have some means of receiving…
First, let us review some of the properties of differentials and…
A unique form of differential pressure-based flow measurement deserves…
Given the ability of pressurized fluids to transmit force over long…
By definition, a source is a device delivering energy into a system,…
In addition to directly performing logic functions, electromechanical…
Control valves are supposed to deliver reliable, repeatable control of…
Tube, like pipe, is a hollow structure designed to provide an enclosed…
To show a practical process example, let’s examine three…
There are many process control applications in the industry where it…
Lipták, Béla G. et al., Instrument Engineers’ Handbook – Process…
An variable-area flowmeter is one where the fluid must pass through a…
There are several different methods useful for causing an AC induction…
It is often useful to express the amplitude of an alternating quantity…
A 4 to 20 mA current signal represents some signal along a 0 to 100…
Perhaps the most confusing aspect of discrete sensors is the…
Using filter cells to eliminate wavelengths associated with…
A chemical reaction resulting in a net release of energy is called…
To better understand the design and operation of self-balancing…
Diagnostic ability is arguably the most difficult skill to develop…
As we have seen, feedforward control is a way to improve the stability…
Weight-based level instruments sense process level in a vessel by…
Multiple accessories exist for pressure-sensing devices to function…
Linearity of Measurement Instruments The purpose of calibration is to…
Some problem-solving techniques are unique to quantitative problems,…
The simplest form of 4-20 mA current loop is the type used to…
