Imagine a liquid-level control system for a vessel, where the position of a level-sensing float sets the…
Textbook
The simplest form of 4-20 mA current loop is the type used to represent the output of a process controller,…
Textbook
Process measurements are often of an analog nature: the temperature of a furnace, the rate of fluid flow…
Textbook
Negative feedback systems, in general, tend to cause confusion for those first learning their fundamental…
Textbook
Perhaps the most important rule of controller tuning is to know the process before attempting to adjust the…
Textbook
Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
Textbook
Modern DC and AC motor drives provide features useful when using electric motors as final control elements.…
Textbook
Feedback Control System Components Before we begin our discussion on process control, we must define a few key…
Textbook
To better understand the design and operation of self-balancing pneumatic mechanisms, it is helpful to examine…
Textbook
There are several different methods useful for causing an AC induction motor to brake, or slow down: DC…
Textbook
The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
Textbook
A bridge circuit is basically a pair of voltage dividers where the circuit output is taken as the difference…
Textbook
Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
Textbook
AC induction motors are based on the principle of a rotating magnetic field produced by a set of stationary…
Textbook
In the United States, the most common language used to program PLCs is Ladder Diagram (LD), also known as…
Textbook
Regulating the electric power sent to an electric motor is a task performed by high-speed switching…
Textbook
The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
Textbook
In addition to directly performing logic functions, electromechanical relays may also be used as interposing…
Textbook
Although it seems each model of PLC has its own idiosyncratic standard for programming, there does exist an…
Textbook
A simple control system drawn in block diagram form looks like this: Information from the measuring device…
Textbook
The fundamental principle of electromagnetism is that an electric current will create a magnetic field at…
Textbook
An important type of “accessory” relay, especially for legacy electromechanical protective relays,…
Textbook
To review, voltage is the measure of potential energy available to electric charges. Current is the uniform…
Textbook
Weight-based level instruments sense process level in a vessel by directly measuring the weight of the vessel.…
Textbook
Temperature measurement devices may be classified into two broad types: contact and non-contact. Contact-type…
Textbook
In our first signal characterization example, we tackle the problem of measuring fluid flow through a pipe. To…
Textbook
In contrast to quantitative tuning procedures where definite numerical values for P, I, and D controller…
Textbook
Calculus. Few areas of mathematics are as powerfully useful in describing and analyzing the physical…
Textbook
A great many precision instruments use the principle of balance to measure some quantity. Perhaps the simplest…
Textbook
A vertical column of fluid generates a pressure at the bottom of the column owing to the action of gravity on…
Textbook
As we have seen, feedforward control is a way to improve the stability of a feedback control system in the…
Textbook
An extremely important topic in engineering is that of transfer functions. Simply defined, a transfer function…
Textbook
“Polyphase” means “many phases,” describing a form of AC electrical system where…
Textbook
Measuring the flow rate of liquid through an open channel is not unlike measuring the flow rate of a liquid…
Textbook
A proximity switch is one detecting the proximity (closeness) of some object. By definition, these switches…
Textbook
A very common form of on/off valve used for pneumatic and hydraulic systems alike is the solenoid valve. A…
Textbook
Any conductor possesses a characteristic called inductance: the ability to store energy in the form of a…
Textbook
Cyber-security seems to have its own vocabulary, ranging from unwieldy technical acronyms to slang terms…
Textbook
Modern DC and AC motor drives provide features useful when using electric motors as final control elements.…
Textbook
A whole class of problem-solving techniques focuses on altering the given problem into a simpler form that is…
Textbook
Facebook
Google
GitHub
Linkedin