Perhaps the most confusing aspect of discrete sensors is the definition of a sensor’s normal status.…
Textbook
Imagine a liquid-level control system for a vessel, where the position of a level-sensing float sets the…
Textbook
A different strategy for controlling the flow of fluid is to insert a rotary element into the flow path.…
Textbook
The electrical conductivity of liquids is an important analytical measurement in many industrial processes.…
Textbook
Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…
Textbook
Any power grid large enough to meet the demand of an entire nation must have multiple generators drawing from…
Textbook
An electromechanical relay is an electrical switch actuated by an electromagnet coil. As switching devices,…
Textbook
An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973, while working for the Xerox research…
Textbook
The advent of “smart” field instruments containing microprocessors has been a great advance for…
Textbook
One very convenient feature of waves is that their properties are universal. Waves of water in the ocean,…
Textbook
Three-phase AC is the dominant mode of electric power generation and distribution in modern societies.…
Textbook
As we have seen, the concept of integration is finding the accumulation of one variable multiplied by another…
Textbook
Some analyzers measure the composition of a process stream by directly immersing the sensing element in that…
Textbook
Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
Textbook
Many years ago, when I was first learning about electricity, I happened to discover a length of coaxial…
Textbook
When control valves operate between fully open and fully shut, they serve much the same purpose in process…
Textbook
In the United States, the most common language used to program PLCs is Ladder Diagram (LD), also known as…
Textbook
Valves can experience a number of problems, most of them either preventable or repairable. These problems can…
Textbook
A simple control system drawn in block diagram form looks like this: Information from the measuring device…
Textbook
The Law of Continuity for fluids states that the product of mass density (\(\rho\)), cross-sectional pipe area…
Textbook
Like so many other industrial data networks, FOUNDATION Fieldbus is an “unswitched” or…
Textbook
A limitation inherent to pneumatic valve actuators is the amount of air flow required to or from the actuator…
Textbook
Level gauges are perhaps the simplest indicating instrument for liquid level in a vessel. They are often found…
Textbook
PID control can be a confusing concept to understand. Here, a brief summary of each term within PID (P. I, and…
Textbook
Coy, John J. et. al. (December 2012) Sampled graphic illustrations from his NASA Reference Publication…
Textbook
One of the most important accessories for any temperature-sensing element is a pressure-tight sheath known as…
Textbook
A 4 to 20 mA current signal represents some signal along a 0 to 100 percent scale. Usually, this scale is…
Textbook
A level switch is one detecting the level of liquid or solid (granules or powder) in a vessel. Level switches…
Textbook
A quantitative PID tuning procedure is a step-by-step approach leading directly to a set of numerical values…
Textbook
A laser is a light source emitting waves of light that not only share the exact same frequency (color)…
Textbook
Most pneumatic instruments use a simple but highly sensitive mechanism for converting mechanical motion into…
Textbook
Electrical Resistance Resistance (\(R\)) is the dissipative opposition to an electric current, analogous to…
Textbook
Feedback obtained from industrial users of FF reveal a common pattern: Fieldbus is a powerful and reliable…
Textbook
The two “process variables” we rely on most heavily in the field of electrical measurement and…
Textbook
The final step in treating wastewater before releasing it into the natural environment is to kill any harmful…
Textbook
A machine in the broad sense of the word is any device designed to translate some form of energy into useful…
Textbook
Instrument technicians should not have to concern themselves over the programming details internal to digital…
Textbook
Negative feedback systems, in general, tend to cause confusion for those first learning their fundamental…
Textbook
Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…
Textbook
The efficient identification and correction of instrument calibration errors is an important function for…
Textbook
Sometimes we encounter a diversity of instrument signal standards in one control system. Such is the case with…
Textbook
The following animation shows how the “rotating” magnetic field of a three-phase AC induction…
Textbook
Certain types of nuclear radiation easily penetrates the walls of industrial vessels, but is attenuated by…
Textbook
Any conductor possesses a characteristic called inductance: the ability to store energy in the form of a…
Textbook
Given the ability of pressurized fluids to transmit force over long distances, it is not surprising that many…
Textbook
Much has been written about the benefits of robust PID control. Increased productivity, decreased equipment…
Textbook
A very simple device used to measure pressure is the manometer: a fluid-filled tube where an applied gas…
Textbook
A simple control system drawn in block diagram form looks like this: Information from the measuring device…
Textbook
Process measurements are often of an analog nature: the temperature of a furnace, the rate of fluid flow…
Textbook
Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…
Textbook
In some process applications, it is important that the control valve be able to completely stop fluid flow…
Textbook
A pressure switch is one detecting the presence of fluid pressure. Pressure switches often use diaphragms or…
Textbook
Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…
Textbook
Converting between disparate units of measurement is the bane of many science students. The problem is worse…
Textbook
Sensors used to measure vibration come in three basic types: displacement, velocity, and acceleration.…
Textbook
The digital multimeter (DMM) is quite possibly the most useful tool in the instrument technician’s…
Textbook
Capacitive level instruments measure electrical capacitance of a conductive rod inserted vertically into a…
Textbook
The Law of Mass Conservation states that matter can neither be created nor destroyed. The Law of Energy…
Textbook
An important legacy technology for all kinds of continuous measurement is the self-balancing system. A…
Textbook
Electromechanical relays may be connected together to perform logic and control functions, acting as logic…
Textbook
Facebook
Google
GitHub
Linkedin