As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
Textbook
In addition to directly performing logic functions, electromechanical relays may also be used as interposing…
Textbook
A bridge circuit is basically a pair of voltage dividers where the circuit output is taken as the difference…
Textbook
The vast majority of PID controllers in service today are digital in nature. Microprocessors executing PID…
Textbook
The simplest form of 4-20 mA current loop is the type used to represent the output of a process controller,…
Textbook
The purpose of a control valve actuator is to provide the motive force to operate a valve mechanism. Both…
Textbook
Perhaps the most important rule of controller tuning is to know the process before attempting to adjust the…
Textbook
Process measurements are often of an analog nature: the temperature of a furnace, the rate of fluid flow…
Textbook
Perhaps the most basic and necessary protective relay function is overcurrent: commanding a circuit breaker to…
Textbook
Although it seems each model of PLC has its own idiosyncratic standard for programming, there does exist an…
Textbook
In order for any PID controller to be practical, it must be able to do more than just implement the PID…
Textbook
AC induction motors are based on the principle of a rotating magnetic field produced by a set of stationary…
Textbook
The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…
Textbook
A simple control system drawn in block diagram form looks like this: Information from the measuring device…
Textbook
Modern DC and AC motor drives provide features useful when using electric motors as final control elements.…
Textbook
Phasors are to AC circuit quantities as polarity is to DC circuit quantities: a way to express the…
Textbook
Negative feedback systems, in general, tend to cause confusion for those first learning their fundamental…
Textbook
An electric motor is often used as a discrete control element in a control system if driving a pump, conveyor…
Textbook
Feedback Control System Components Before we begin our discussion on process control, we must define a few key…
Textbook
In the United States, the most common language used to program PLCs is Ladder Diagram (LD), also known as…
Textbook
A very common method for directly controlling low flow rates of fluids is to use a device known as a metering…
Textbook
A control strategy similar to ratio control is relation control. This is similar to ratio control in that a…
Textbook
These fortifications focus on human behavior rather than system design or component selection. In some ways…
Textbook
A vertical column of fluid generates a pressure at the bottom of the column owing to the action of gravity on…
Textbook
Regardless of valve type, all stem-actuated control valves require some form of seal allowing motion of the…
Textbook
In this section I will show screenshots from a process loop simulation program illustrating the effectiveness…
Textbook
As defined previously, calibration means the comparison and adjustment (if necessary) of an instrument’s…
Textbook
A unique form of technical diagram for describing the abstract functions comprising a control system (e.g. PID…
Textbook
DC electric current signals may also be used to communicate process measurement information from transmitters…
Textbook
An interesting parallel to the “unity fraction” unit conversion technique is something referred to…
Textbook
There are many process control applications in the industry where it is desirable to have multiple control…
Textbook
Fieldbus devices require far more attention in their initial setup and commissioning than their analog…
Textbook
Sometimes we encounter a diversity of instrument signal standards in one control system. Such is the case with…
Textbook
Once while working as an instrument technician in an aluminum foundry, a mechanic asked me what it was that I…
Textbook
To show a practical process example, let’s examine three diagrams for a compressor control system,…
Textbook
Tube, like pipe, is a hollow structure designed to provide an enclosed pathway for fluids to flow. In the case…
Textbook
A temperature switch is one detecting the temperature of some substance. Temperature switches often use…
Textbook
Weight-based level instruments sense process level in a vessel by directly measuring the weight of the vessel.…
Textbook
Any conductor possesses a characteristic called inductance: the ability to store energy in the form of a…
Textbook
There is much to be said for neatness of assembly in electrical signal wiring. Even though the electrons…
Textbook
Disconnect Switches Disconnects are switches designed to isolate sections of a power system in case of damage…
Textbook
Weight-based level instruments sense process level in a vessel by directly measuring the weight of the vessel.…
Textbook
Visualizing the actions of P, I, and D tuning parameters using graphs is extremely useful in predicting the…
Textbook
Solids tend to expand when heated. The amount that a solid sample will expand with increased temperature…
Textbook
Volumes could be written about poor diagnostic technique. The following mistakes are not intended to comprise…
Textbook
Diagnostic ability is arguably the most difficult skill to develop within a student, and also the most…
Textbook
An exciting development in industrial instrumentation is the WirelessHART radio communication standard,…
Textbook
Control valves are supposed to deliver reliable, repeatable control of process fluid flow rate over a wide…
Textbook
Since we often use electricity to convey energy from one location to another, it is important to be able to…
Textbook
A powerful mathematical concept useful for analyzing practically any physical system – electrical…
Textbook
While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
Textbook
Once while working as an instrument technician in an aluminum foundry, a mechanic asked me what it was that I…
Textbook
Textbook
Capacitance Any two electrical conductors separated by an insulating medium possess the characteristic called…
Textbook
Those familiar with industrial instrumentation will find much within the electric power industry remarkably…
Textbook
The two “process variables” we rely on most heavily in the field of electrical measurement and…
Textbook
When I began teaching full-time in 1998, most of what I thought I understood about good teaching was actually…
Textbook
As previously defined, calibration refers to the checking and adjustment of an instrument so that its output…
Textbook
All masses require force to accelerate (we can also think of this in terms of the mass generating a reaction…
Textbook
In the United States, the most common language used to program PLCs is Ladder Diagram (LD), also known as…
Textbook
Facebook
Google
GitHub
Linkedin