Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
Textbook
As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
Textbook
As we have seen, the concept of differentiation is finding the rate-of-change of one variable compared to…
Textbook
Imagine a major marathon race, where hundreds of runners gather in one place to compete. When the starting gun…
Textbook
Valves can experience a number of problems, most of them either preventable or repairable. These problems can…
Textbook
The Law of Continuity for fluids states that the product of mass density (\(\rho\)), cross-sectional pipe area…
Textbook
The two “process variables” we rely on most heavily in the field of electrical measurement and…
Textbook
Process measurements are often of an analog nature: the temperature of a furnace, the rate of fluid flow…
Textbook
“Radio” systems use electromagnetic fields to communicate information over long distances through…
Textbook
There are many process control applications in the industry where it is desirable to have multiple control…
Textbook
Diagnostic ability is arguably the most difficult skill to develop within a student, and also the most…
Textbook
The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
Textbook
Perhaps the most valuable skill an instrument technician can possess is the ability to efficiently diagnose…
Textbook
The efficient identification and correction of instrument calibration errors is an important function for…
Textbook
Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…
Textbook
Data-processing modules within FF systems are known as function blocks. Sometimes these blocks serve merely to…
Textbook
A technological advance introduced in the late 1980’s was HART, an acronym standing for Highway…
Textbook
Hydrogen ion activity in aqueous (water-solvent) solutions is a very important parameter for a wide variety of…
Textbook
One of the fundamental laws of electric circuits is Kirchhoff’s Current Law, which states the algebraic…
Textbook
Instrument technicians should not have to concern themselves over the programming details internal to digital…
Textbook
A chemical reaction resulting in a net release of energy is called exothermic. Conversely, a chemical reaction…
Textbook
When a high-energy photon strikes an atom, it may eject one of the lower-level electrons from its shell,…
Textbook
As we have seen, the concept of differentiation is finding the rate-of-change of one variable compared to…
Textbook
Given the ability of pressurized fluids to transmit force over long distances, it is not surprising that many…
Textbook
The reason why a pneumatic control valve’s stem position corresponds linearly to the amount of air…
Textbook
There are many process control applications in the industry where it is desirable to have multiple control…
Textbook
As we have seen, the concept of integration is finding the accumulation of one variable multiplied by another…
Textbook
At the next OSI Reference Model layer (layer 4) is a set of protocols specifying how reliable communication…
Textbook
A 4 to 20 mA current signal represents some signal along a 0 to 100 percent scale. Usually, this scale is…
Textbook
A variety of technologies exist to measure the quantity of stored material in a vessel. For liquid…
Textbook
When control valves operate between fully open and fully shut, they serve much the same purpose in process…
Textbook
Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…
Textbook
In a manually-controlled process, a human operator directly actuates some form of final control element…
Textbook
Layer 1 of the OSI Reference Model is where we define the “physical” elements of a digital data…
Textbook
A very common form of on/off valve used for pneumatic and hydraulic systems alike is the solenoid valve. A…
Textbook
A form of protection against faults on long-distance power lines is called distance relaying, so named because…
Textbook
A pneumatic controller receives a process variable (PV) signal as a variable air pressure, compares that…
Textbook
Learning PLC programming is a very important skill. If your job involves programming, then you will likely…
Textbook
In November of 2007 a new computer virus was submitted to a virus scanning service. The purpose of this new…
Textbook
A vertical column of fluid generates a pressure at the bottom of the column owing to the action of gravity on…
Textbook
Textbook
Valve actuators provide force to move control valve trim. For precise positioning of a control valve, there…
Textbook
A level switch is one detecting the level of liquid or solid (granules or powder) in a vessel. Level switches…
Textbook
Using filter cells to eliminate wavelengths associated with interfering gases is called positive filtering in…
Textbook
(Will be addressed in future versions of this book)
Textbook
Any power grid large enough to meet the demand of an entire nation must have multiple generators drawing from…
Textbook
The digital multimeter (DMM) is quite possibly the most useful tool in the instrument technician’s…
Textbook
Disconnect Switches Disconnects are switches designed to isolate sections of a power system in case of damage…
Textbook
The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
Textbook
As previously defined, calibration refers to the checking and adjustment of an instrument so that its output…
Textbook
The majority of flowmeter technologies operate on the principle of interpreting fluid flow based on the…
Textbook
Binary patterns are not just able to represent numerical values. Given a standardized code, they may represent…
Textbook
The following photograph shows a large air blower in a wastewater treatment facility equipped with a…
Textbook
In contrast to quantitative tuning procedures where definite numerical values for P, I, and D controller…
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 pneumatic controller receives a process variable (PV) signal as a variable air pressure, compares that…
Textbook
A damper (otherwise known as a louvre) is a multi-element flow control device generally used to throttle large…
Textbook
Every programmable logic controller must have some means of receiving and interpreting signals from real-world…
Textbook
An interesting parallel to the “unity fraction” unit conversion technique is something referred to…
Textbook
A wise PLC programmer once told me that the first thing any aspiring programmer should learn about the PLC…
Textbook
Facebook
Google
GitHub
Linkedin