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Gas Filter Correlation (GFC) Spectroscopy

Gas Filter Correlation (GFC) Spectroscopy

Using filter cells to eliminate wavelengths associated with interfering gases is called positive filtering in…


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Polyphase AC Power

Polyphase AC Power

“Polyphase” means “many phases,” describing a form of AC electrical system where…


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Electrical Signal and Control Wiring

Electrical Signal and Control Wiring

There is much to be said for neatness of assembly in electrical signal wiring. Even though the electrons…


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Ladder Diagram (LD) Programming Contacts and Coils

Ladder Diagram (LD) Programming Contacts and Coils

In the United States, the most common language used to program PLCs is Ladder Diagram (LD), also known as…


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On/off Electric Motor Control Circuits

On/off Electric Motor Control Circuits

An electric motor is often used as a discrete control element in a control system if driving a pump, conveyor…


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Auxiliary and Lockout (86) Relays

Auxiliary and Lockout (86) Relays

An important type of “accessory” relay, especially for legacy electromechanical protective relays,…


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Logic Programming in PLCs

Logic Programming in PLCs

Although it seems each model of PLC has its own idiosyncratic standard for programming, there does exist an…


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Use of Line Reactors

Use of Line Reactors

Regulating the electric power sent to an electric motor is a task performed by high-speed switching…


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Circuit Breakers and Disconnects

Circuit Breakers and Disconnects

Disconnect Switches Disconnects are switches designed to isolate sections of a power system in case of damage…


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AC Motor Braking

AC Motor Braking

There are several different methods useful for causing an AC induction motor to brake, or slow down: DC…


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Differential (87) Current Protection

Differential (87) Current Protection

One of the fundamental laws of electric circuits is Kirchhoff’s Current Law, which states the algebraic…


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Fluid Mechanics

Fluid Mechanics

A fluid is any substance having the ability to flow: to freely change shape and move under the influence of a…


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Relay Circuits and Ladder Diagrams

Relay Circuits and Ladder Diagrams

Electromechanical relays may be connected together to perform logic and control functions, acting as logic…


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Teaching Technical Practices (Labwork)

Teaching Technical Practices (Labwork)

Labwork is an essential part of any science-based curriculum. Here, much improvement may be made over the…


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Introduction to Power System Automation

Introduction to Power System Automation

Those familiar with industrial instrumentation will find much within the electric power industry remarkably…


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Classified Areas and Electrical Safety Measures

Classified Areas and Electrical Safety Measures

Any physical location in an industrial facility harboring the potential of explosion due to the presence of…


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Ladder Diagram (LD) Structure Commands

Ladder Diagram (LD) Structure Commands

The simple PLC ladder diagram (LD) commands consist of contacts and coils, arranged in sequences that mimic…


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ANSI/IEEE Function Number Codes

ANSI/IEEE Function Number Codes

In the United States, the ANSI and IEEE organizations have standardized a set of numerical codes referring to…


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How to Teach Yourself PLC Programming

How to Teach Yourself PLC Programming

Learning PLC programming is a very important skill. If your job involves programming, then you will likely…


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Digital Multimeter (DMM) Tips and Tricks

Digital Multimeter (DMM) Tips and Tricks

The digital multimeter (DMM) is quite possibly the most useful tool in the instrument technician’s…


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Legal Code

Legal Code

Creative Commons Attribution 4.0 International Public License By exercising the Licensed Rights (defined…


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Understanding How Three-phase Electric Motors Work

Understanding How Three-phase Electric Motors Work

The key to understanding how three-phase electric motors work is to have an accurate mental picture of the…


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EIA/TIA-232, 422, and 485 Networks

EIA/TIA-232, 422, and 485 Networks

Some of the simplest types of digital communication networks found in industry are defined by the EIA…


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Pressure Switches

Pressure Switches

A pressure switch is one that detects the presence of fluid pressure. Pressure switches often use diaphragms…


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Safety Gas Analyzers

Safety Gas Analyzers

Process analyzers measure the concentration of specific substances for the purpose of measuring and/or…


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Error Corrections

Error Corrections

Abdelaziz, Ahmed (June 2014) Identified numerous typographical errors throughout the book, mostly repeated…


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Understanding the “Normal” Status of a Process Switch

Understanding the “Normal” Status of a Process Switch

Perhaps the most confusing aspect of discrete sensors is the definition of a sensor’s normal status.…


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Proximity Switches

Proximity Switches

A proximity switch is one detecting the proximity (closeness) of some object. By definition, these switches…


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the Negative Consequences of Poor PID Controller Tuning

the Negative Consequences of Poor PID Controller Tuning

Much has been written about the benefits of robust PID control. Increased productivity, decreased equipment…


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AC Motor Braking

AC Motor Braking

There are several different methods useful for causing an AC induction motor to brake, or slow down: DC…


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Human-Machine Interfaces (HMIs)

Human-Machine Interfaces (HMIs)

Human-machine interfaces, or HMIs, are a critical part of nearly all control systems, complementing the…


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The s Variable: Euler’s Relation and Phasor Expressions of Waveforms

The s Variable: Euler’s Relation and Phasor Expressions of Waveforms

A powerful mathematical concept useful for analyzing practically any physical system – electrical…


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Level Sensor Accessories

Level Sensor Accessories

Disturbances in the liquid tend to complicate liquid level measurement. These disturbances may result from…


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References

References

Lipták, Béla G. et al., Instrument Engineers’ Handbook – Process Measurement and Analysis Volume I,…


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Boiler Water Level Control System Example

Boiler Water Level Control System Example

Steam boilers are very common in industry, principally because steam power is so useful. Common uses for steam…


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Different PID Equations

Different PID Equations

For better or worse, there are no fewer than three different forms of PID equations implemented in modern PID…


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Dimensional Analysis

Dimensional Analysis

An interesting parallel to the “unity fraction” unit conversion technique is something referred to…


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Filled-bulb Temperature Sensors

Filled-bulb Temperature Sensors

Filled-bulb systems exploit the principle of fluid expansion to measure temperature. If a fluid is enclosed in…


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What is Electrical Power?

What is Electrical Power?

Since we often use electricity to convey energy from one location to another, it is important to be able to…


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Weighfeeders

Weighfeeders

A special type flowmeter suited for powdered or granular solids is the weighfeeder. One of the most common…


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Pilot Valves and Pneumatic Amplifying Relays

Pilot Valves and Pneumatic Amplifying Relays

Self-balancing mechanisms consisting solely of a baffle/nozzle detector coupled to a feedback bellows, while…


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