DC electric current signals may also be used to communicate process measurement information from transmitters…
Textbook
One very convenient feature of waves is that their properties are universal. Waves of water in the ocean,…
Textbook
It is possible to convey electrical power and communicate analog information over the same two wires using 4…
Textbook
Every flow-measuring instrument exploits a physical principle to measure the flow rate of fluid stream.…
Textbook
Filled-bulb systems exploit the principle of fluid expansion to measure temperature. If a fluid is enclosed in…
Textbook
A wise PLC programmer once told me that the first thing any aspiring programmer should learn about the PLC…
Textbook
In this section I will show screenshots from a process loop simulation program illustrating the effectiveness…
Textbook
Most pneumatic instruments use a simple but highly sensitive mechanism for converting mechanical motion into…
Textbook
As described earlier in this chapter, calibration refers to the adjustment of an instrument so its output…
Textbook
When control valves operate between fully open and fully shut, they serve much the same purpose in process…
Textbook
Another category of control strategies involves the use of signal relays or function blocks with the ability…
Textbook
Control valves are supposed to deliver reliable, repeatable control of process fluid flow rate over a wide…
Textbook
All masses require force to accelerate (we can also think of this in terms of the mass generating a reaction…
Textbook
To understand just how different FOUNDATION Fieldbus is from other digital instrument systems, consider a…
Textbook
A positive displacement flowmeter is a cyclic mechanism built to pass a fixed volume of fluid through with…
Textbook
A pneumatic controller receives a process variable (PV) signal as a variable air pressure, compares that…
Textbook
A very common form of on/off valve used for pneumatic and hydraulic systems alike is the solenoid valve. A…
Textbook
“Polyphase” means “many phases,” describing a form of AC electrical system where…
Textbook
Perhaps the most important rule to obey when using pneumatic instruments is to maintain clean and dry…
Textbook
A completely different way of measuring liquid level in vessels is to bounce a traveling wave off the surface…
Textbook
Volumes could be written about poor diagnostic technique. The following mistakes are not intended to comprise…
Textbook
In addition to directly performing logic functions, electromechanical relays may also be used as interposing…
Textbook
Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…
Textbook
The advent of “smart” field instruments containing microprocessors has been a great advance for…
Textbook
In the United States, the ANSI and IEEE organizations have standardized a set of numerical codes referring to…
Textbook
Disturbances in the liquid tend to complicate liquid level measurement. These disturbances may result from…
Textbook
Regardless of valve type, all stem-actuated control valves require some form of seal allowing motion of the…
Textbook
The vast majority of modern process transmitters (both analog and digital) come equipped with a feature known…
Textbook
Diagnostic ability is arguably the most difficult skill to develop within a student, and also the most…
Textbook
Feedback Control System Components Before we begin our discussion on process control, we must define a few key…
Textbook
The two “process variables” we rely on most heavily in the field of electrical measurement and…
Textbook
Solids tend to expand when heated. The amount that a solid sample will expand with increased temperature…
Textbook
Virtually any mass above absolute zero temperature emits electromagnetic radiation (photons, or light) as a…
Textbook
Multiple accessories exist for pressure-sensing devices to function optimally in challenging process…
Textbook
Current is the name we give to the motion of electric charges from a point of high potential to a point of low…
Textbook
One of the most important accessories for any temperature-sensing element is a pressure-tight sheath known as…
Textbook
Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
Textbook
The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
Textbook
Tube, like pipe, is a hollow structure designed to provide an enclosed pathway for fluids to flow. In the case…
Textbook
A chemical reaction resulting in a net release of energy is called exothermic. Conversely, a chemical reaction…
Textbook
Pipe is a hollow structure designed to provide an enclosed pathway for fluids to flow, usually manufactured…
Textbook
Every programmable logic controller must have some means of receiving and interpreting signals from real-world…
Textbook
Capacitance Any two electrical conductors separated by an insulating medium possess the characteristic called…
Textbook
There are multiple motives for compromising the security of an industrial control system, some of which…
Textbook
As we have seen, the concept of integration is finding the accumulation of one variable multiplied by another…
Textbook
Perhaps the most important rule to obey when using pneumatic instruments is to maintain clean and dry…
Textbook
A simple control system drawn in block diagram form looks like this: Information from the measuring device…
Textbook
Displacer level instruments exploit Archimedes’ Principle to detect liquid level by continuously…
Textbook
Current is the name we give to the motion of electric charges from a point of high potential to a point of low…
Textbook
At the root of successful system diagnosis is a rigorous adherence to scientific reasoning. There exists no…
Textbook
Temperature measurement devices may be classified into two broad types: contact and non-contact. Contact-type…
Textbook
A control strategy similar to ratio control is relation control. This is similar to ratio control in that a…
Textbook
One very convenient feature of waves is that their properties are universal. Waves of water in the ocean,…
Textbook
A level switch is one detecting the level of liquid or solid (granules or powder) in a vessel. Level switches…
Textbook
Much of our knowledge about atomic structure comes from experimental data relating the interaction between…
Textbook
Learning is not merely a process of information transfer. It is first and foremost a transformation of…
Textbook
The disadvantages of pneumatic instruments are painfully evident to anyone familiar with both pneumatic and…
Textbook
Shown here is a partial listing of principles applied in the subject matter of this chapter, given for the…
Textbook
A vertical column of fluid generates a pressure at the bottom of the column owing to the action of gravity on…
Textbook
Linearity of Measurement Instruments The purpose of calibration is to ensure the input and output of an…
Textbook
Facebook
Google
GitHub
Linkedin