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Pressure Sensor Accessories

Pressure Sensor Accessories

Multiple accessories exist for pressure-sensing devices to function optimally in challenging process…


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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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Temperature Sensor Accessories

Temperature Sensor Accessories

One of the most important accessories for any temperature-sensing element is a pressure-tight sheath known as…


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“Normal” status of a Process Switch

“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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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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Electromagnetism Basics

Electromagnetism Basics

The fundamental principle of electromagnetism is that an electric current will create a magnetic field at…


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Practical PID Controller Features

Practical PID Controller Features

In order for any PID controller to be practical, it must be able to do more than just implement the PID…


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Open-ended, Shorted and Properly Terminated Transmission Lines

Open-ended, Shorted and Properly Terminated Transmission Lines

Many years ago, when I was first learning about electricity, I happened to discover a length of coaxial…


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Applications of Spectroscopy for Analytical Measurement

Applications of Spectroscopy for Analytical Measurement

Much of our knowledge about atomic structure comes from experimental data relating the interaction between…


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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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Resistance, Reactance and Impedance

Resistance, Reactance and Impedance

Electrical Resistance Resistance (\(R\)) is the dissipative opposition to an electric current, analogous to…


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Antennas and Resonant Circuits (Tank Circuits)

Antennas and Resonant Circuits (Tank Circuits)

Capacitors store energy in electric fields, proportional to the square of voltage. Inductors store energy in…


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Vibration Physics

Vibration Physics

One very convenient feature of waves is that their properties are universal. Waves of water in the ocean,…


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Valve Seat Leakage

Valve Seat Leakage

In some process applications, it is important that the control valve be able to completely stop fluid flow…


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Sliding-stem Valves

Sliding-stem Valves

A sliding-stem valve body is one where the moving parts slide with a linear motion. Some examples of…


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Null-balance Voltage Measurement

Null-balance Voltage Measurement

A number of different sensors used in instrumentation generate DC voltage signals proportional to the process…


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Temperature Sensor Accessories

Temperature Sensor Accessories

One of the most important accessories for any temperature-sensing element is a pressure-tight sheath known as…


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Laser Spectroscopy

Laser Spectroscopy

A laser is a light source emitting waves of light that not only share the exact same frequency (color)…


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Analog Electronic PID Controllers

Analog Electronic PID Controllers

Constructing PID control systems using discrete components is a fairly simple method involving operational…


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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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The Basics of Control Relays

The Basics of Control Relays

An electromechanical relay is an electrical switch actuated by an electromagnet coil. As switching devices,…


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Non-dispersive Luft Detector Spectroscopy

Non-dispersive Luft Detector Spectroscopy

Non-dispersive analysis, while newer in discovery than dispersive analysis (Isaac Newton’s 17th-century…


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Ultrasonic (Sound) Echo Level Measurement

Ultrasonic (Sound) Echo Level Measurement

A completely different way of measuring liquid level in vessels is to bounce a traveling wave off the surface…


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Teaching Diagnostic Principles and Practices

Teaching Diagnostic Principles and Practices

Diagnostic ability is arguably the most difficult skill to develop within a student, and also the most…


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Principles, not Procedures

Principles, not Procedures

One of the marks of a successful problem-solver is a habit of applying general principles to every new problem…


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Safety Instrumented Functions and Systems

Safety Instrumented Functions and Systems

A Safety Instrumented Function, or SIF, is one or more components designed to execute a specific…


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FOUNDATION Fieldbus H1 Protocol Segment Troubleshooting

FOUNDATION Fieldbus H1 Protocol Segment Troubleshooting

Feedback obtained from industrial users of FF reveal a common pattern: Fieldbus is a powerful and reliable…


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Laminar Flowmeters

Laminar Flowmeters

A unique form of differential pressure-based flow measurement deserves its own section in this flow…


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National Institute of Standards and Technology (NIST) Traceability

National Institute of Standards and Technology (NIST) Traceability

As defined previously, calibration means the comparison and adjustment (if necessary) of an instrument’s…


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2-wire (“loop-powered”) Transmitter Current Loops

2-wire (“loop-powered”) Transmitter Current Loops

It is possible to convey electrical power and communicate analog information over the same two wires using 4…


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Chemical Reactor Temperature Control Example

Chemical Reactor Temperature Control Example

Sometimes we encounter a diversity of instrument signal standards in one control system. Such is the case with…


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Level Switches

Level Switches

A level switch is one detecting the level of liquid or solid (granules or powder) in a vessel. Level switches…


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Interconnected Generators

Interconnected Generators

Any power grid large enough to meet the demand of an entire nation must have multiple generators drawing from…


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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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The Concept of Differentiation

The Concept of Differentiation

Suppose we wished to measure the rate of propane gas flow through a hose to a torch: Flowmeters appropriate…


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Non-contact Temperature Sensors

Non-contact Temperature Sensors

Virtually any mass above absolute zero temperature emits electromagnetic radiation (photons, or light) as a…


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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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Atomic Theory and Chemical Symbols

Atomic Theory and Chemical Symbols

The three “elementary” particles of matter comprising all atoms are electrons, protons, and…


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Common Control Valve Problems

Common Control Valve Problems

Valves can experience a number of problems, most of them either preventable or repairable. These problems can…


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Control Valve Actuators

Control Valve Actuators

The purpose of a control valve actuator is to provide the motive force to operate a valve mechanism. Both…


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Wastewater Disinfection Example

Wastewater Disinfection Example

The final step in treating wastewater before releasing it into the natural environment is to kill any harmful…


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Teaching Technical Theory

Teaching Technical Theory

Learning is not merely a process of information transfer. It is first and foremost a transformation of…


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Split-range Control

Split-range Control

There are many process control applications in the industry where it is desirable to have multiple control…


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Pressure Sensor Accessories

Pressure Sensor Accessories

Multiple accessories exist for pressure-sensing devices to function optimally in challenging process…


Textbook