Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
Textbook
One of the fundamental laws of electric circuits is Kirchhoff’s Current Law, which states the algebraic…
Textbook
As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
Textbook
So far we have just looked at instruments that sense, control, and influence process variables. Transmitters,…
Textbook
A great many precision instruments use the principle of balance to measure some quantity. Perhaps the simplest…
Textbook
To show a practical process example, let’s examine three diagrams for a compressor control system,…
Textbook
In November of 2007 a new computer virus was submitted to a virus scanning service. The purpose of this new…
Textbook
Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
Textbook
pH is the measurement of the hydrogen ion activity in a liquid solution. It is one of the most common forms of…
Textbook
A sliding-stem valve body is one where the moving parts slide with a linear motion. Some examples of…
Textbook
Measuring the flow rate of liquid through an open channel is not unlike measuring the flow rate of a liquid…
Textbook
Self-balancing pneumatic instrument mechanisms are very similar to negative-feedback operational amplifier…
Textbook
An electric motor is often used as a discrete control element in a control system if driving a pump, conveyor…
Textbook
Learning is not merely a process of information transfer. It is first and foremost a transformation of…
Textbook
Level gauges are perhaps the simplest indicating instrument for liquid level in a vessel. They are often found…
Textbook
Steam boilers are very common in industry, principally because steam power is so useful. Common uses for steam…
Textbook
Many years ago, when I was first learning about electricity, I happened to discover a length of coaxial…
Textbook
The transformer is one of the most important components in all of AC circuitry. Principally used to…
Textbook
Mechanical pressure-sensing elements include the bellows, the diaphragm, and the bourdon tube. Each of these…
Textbook
A unique form of technical diagram for describing the abstract functions comprising a control system (e.g. PID…
Textbook
The term “grid” refers to the conductors and equipment interconnecting power sources to power…
Textbook
Binary patterns are not just able to represent numerical values. Given a standardized code, they may represent…
Textbook
Electrical Resistance Resistance (\(R\)) is the dissipative opposition to an electric current, analogous to…
Textbook
Disturbances in the liquid tend to complicate liquid level measurement. These disturbances may result from…
Textbook
Volumes could be written about poor diagnostic technique. The following mistakes are not intended to comprise…
Textbook
Self-balancing pneumatic instrument mechanisms are very similar to negative-feedback operational amplifier…
Textbook
The two “process variables” we rely on most heavily in the field of electrical measurement and…
Textbook
An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973, while working for the Xerox research…
Textbook
When control valves operate between fully open and fully shut, they serve much the same purpose in process…
Textbook
Several different technologies exist for the conversion of fluid pressure into an electrical signal response.…
Textbook
Any conductor possesses a characteristic called inductance: the ability to store energy in the form of a…
Textbook
A temperature switch is one detecting the temperature of some substance. Temperature switches often use…
Textbook
As defined previously, calibration means the comparison and adjustment (if necessary) of an instrument’s…
Textbook
Like many other mathematical operations, the derivative and the integral perform inverse operations from each…
Textbook
In addition to Ohm’s Law, we have a set of rules describing how voltages, currents, and resistances…
Textbook
DC electric motors generate torque by a reaction between two magnetic fields: one field established by…
Textbook
As we have seen, the concept of differentiation is finding the rate-of-change of one variable compared to…
Textbook
The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
Textbook
An important type of “accessory” relay, especially for legacy electromechanical protective relays,…
Textbook
A very simple device used to measure pressure is the manometer: a fluid-filled tube where an applied gas…
Textbook
Sample sizes of chemical substances are often measured in moles. One mole of a substance is defined as a…
Textbook
Abdelaziz, Ahmed (June 2014) Identified numerous typographical errors throughout the book, mostly repeated…
Textbook
Impedance in a series circuit is the orthogonal sum of resistance and reactance: \[Z = \sqrt{R^2 + (X_L -…
Textbook
A temperature switch is one detecting the temperature of some substance. Temperature switches often use…
Textbook
The final element of PID control is the “D” term, which stands for derivative. This is a calculus…
Textbook
Although analog electronic process controllers are considered a newer technology than pneumatic process…
Textbook
“Polyphase” means “many phases,” describing a form of AC electrical system where…
Textbook
Every flow-measuring instrument exploits a physical principle to measure the flow rate of fluid stream.…
Textbook
Once while working as an instrument technician in an aluminum foundry, a mechanic asked me what it was that I…
Textbook
The next level of detail is the Process and Instrument Diagram, or P&ID. Here, we see a “zooming…
Textbook
Cyber-security seems to have its own vocabulary, ranging from unwieldy technical acronyms to slang terms…
Textbook
Perhaps the simplest form of solid or liquid level measurement is with a float: a device that rides on the…
Textbook
(Will be addressed in future versions of this book)
Textbook
Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
Textbook
Light has long been used as a long-range signaling medium. While communication by light through open air is…
Textbook
The very purpose of physics is to quantitatively describe and explain the physical world in as few terms as…
Textbook
A chemical reaction resulting in a net release of energy is called exothermic. Conversely, a chemical reaction…
Textbook
One of the most common, and most useful, pressure measuring instruments in industry is the differential…
Textbook
A machine in the broad sense of the word is any device designed to translate some form of energy into useful…
Textbook
A completely different way of measuring liquid level in vessels is to bounce a traveling wave off the surface…
Textbook
Facebook
Google
GitHub
Linkedin