Latest Sensors & Instruments Education

Categories

Thermocouple Types, Junctions, Connector and Tip Styles

Thermocouple Types, Junctions, Connector and Tip Styles

RTDs are completely passive sensing elements, requiring the application of an externally-sourced electric…


Textbook

Digital Representation of Numerical Data

Digital Representation of Numerical Data

Process measurements are often of an analog nature: the temperature of a furnace, the rate of fluid flow…


Textbook

Troubleshooting Current Loops

Troubleshooting Current Loops

A fundamental principle in instrumentation system troubleshooting is that every instrument has at least one…


Textbook

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…


Textbook

Pressure Switches

Pressure Switches

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


Textbook

Memory Maps and I/O Addressing

Memory Maps and I/O Addressing

A wise PLC programmer once told me that the first thing any aspiring programmer should learn about the PLC…


Textbook

Digital Representation of Text

Digital Representation of Text

Binary patterns are not just able to represent numerical values. Given a standardized code, they may represent…


Textbook

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…


Textbook

Measuring Electrical Conductivity

Measuring Electrical Conductivity

The electrical conductivity of liquids is an important analytical measurement in many industrial processes.…


Textbook

Transfer Function Analysis

Transfer Function Analysis

An extremely important topic in engineering is that of transfer functions. Simply defined, a transfer function…


Textbook

Resistance, Reactance, and Impedance

Resistance, Reactance, and Impedance

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


Textbook

Human-Machine Interfaces (HMIs)

Human-Machine Interfaces (HMIs)

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


Textbook

Analytical Measurements of Chemical Compositions

Analytical Measurements of Chemical Compositions

A great many chemical composition measurements may be made indirectly by means of electricity, if those…


Textbook

Interconnected Generators

Interconnected Generators

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


Textbook

Indicators, Recorders, Process Switches and Alarms

Indicators, Recorders, Process Switches and Alarms

So far we have just looked at instruments that sense, control, and influence process variables. Transmitters,…


Textbook

Supervisory Control

Supervisory Control

In a manually-controlled process, a human operator directly actuates some form of final control element…


Textbook

Zero and Span Adjustments (Analog Instruments)

Zero and Span Adjustments (Analog Instruments)

Linearity of Measurement Instruments The purpose of calibration is to ensure the input and output of an…


Textbook

Digital PID Algorithms

Digital PID Algorithms

Instrument technicians should not have to concern themselves over the programming details internal to digital…


Textbook

Understanding Electrical Power Grids

Understanding Electrical Power Grids

The term “grid” refers to the conductors and equipment interconnecting power sources to power…


Textbook

Numerical Integration

Numerical Integration

As we have seen, the concept of integration is finding the accumulation of one variable multiplied by another…


Textbook

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…


Textbook

Proper Care and Feeding of Pneumatic Instruments

Proper Care and Feeding of Pneumatic Instruments

Perhaps the most important rule to obey when using pneumatic instruments is to maintain clean and dry…


Textbook

Pneumatic Actuator Response

Pneumatic Actuator Response

A limitation inherent to pneumatic valve actuators is the amount of air flow required to or from the actuator…


Textbook

Understanding the Calculus Concepts of Differentiation and Integration

Understanding the Calculus Concepts of Differentiation and Integration

The following animation shows the calculus concepts of differentiation and integration (with respect to time)…


Textbook

Supervisory Control

Supervisory Control

In a manually-controlled process, a human operator directly actuates some form of final control element…


Textbook

Proportional-only Control

Proportional-only Control

Imagine a liquid-level control system for a vessel, where the position of a level-sensing float directly sets…


Textbook

Techniques for Analyzing Control Strategies

Techniques for Analyzing Control Strategies

Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…


Textbook

Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)

Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)

At the next OSI Reference Model layer (layer 4) is a set of protocols specifying how reliable communication…


Textbook

Differential Pressure Transmitters

Differential Pressure Transmitters

One of the most common, and most useful, pressure measuring instruments in industry is the differential…


Textbook

Analysis of Practical Pneumatic Instruments

Analysis of Practical Pneumatic Instruments

To better understand the design and operation of self-balancing pneumatic mechanisms, it is helpful to examine…


Textbook

Ethernet networks: Repeaters, Cabling and Switching Hubs

Ethernet networks: Repeaters, Cabling and Switching Hubs

An engineer named Bob Metcalfe conceived the idea of Ethernet in 1973, while working for the Xerox research…


Textbook

Electrical Resistance and Ohm’s Law

Electrical Resistance and Ohm’s Law

To review, voltage is the measure of potential energy available to electric charges. Current is the uniform…


Textbook

Basic Operation of a Gas Chromatograph

Basic Operation of a Gas Chromatograph

This animation shows the basic operation of a gas chromatograph, showing the separation of different molecular…


Textbook

Temperature Sensor Accessories

Temperature Sensor Accessories

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


Textbook

4-wire “Passive” Versus “Active” Output Transmitters

4-wire “Passive” Versus “Active” Output Transmitters

Some self-powered (4-wire) analog electronic transmitters are designed to behave as electrical loads rather…


Textbook

Common Diagnostic Mistakes in Control Systems

Common Diagnostic Mistakes in Control Systems

Volumes could be written about poor diagnostic technique. The following mistakes are not intended to comprise…


Textbook

Practical Topic Coverage

Practical Topic Coverage

Nearly every technical course teaches and tests students on definitions, basic concepts, and at least some…


Textbook

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…


Textbook

How Derivatives and Integrals Relate to One Another

How Derivatives and Integrals Relate to One Another

Like many other mathematical operations, the derivative and the integral perform inverse operations from each…


Textbook

Resistance, Reactance, and Impedance

Resistance, Reactance, and Impedance

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


Textbook

Actuator Bench-set

Actuator Bench-set

Valve actuators provide force to move control valve trim. For precise positioning of a control valve, there…


Textbook

Fiber Optic Data Communication

Fiber Optic Data Communication

Light has long been used as a long-range signaling medium. While communication by light through open air is…


Textbook

Ions in Liquid Solutions

Ions in Liquid Solutions

Many liquid substances undergo a process whereby their constituent molecules split into positively and…


Textbook

Understanding the Calculus Concepts of Differentiation and Integration

Understanding the Calculus Concepts of Differentiation and Integration

The following animation shows the calculus concepts of differentiation and integration (with respect to time)…


Textbook

Electrical Pressure Elements

Electrical Pressure Elements

Several different technologies exist for the conversion of fluid pressure into an electrical signal response.…


Textbook

Supervisory Control

Supervisory Control

In a manually-controlled process, a human operator directly actuates some form of final control element…


Textbook

LRV and URV Settings, Digital Trim (Digital Transmitters)

LRV and URV Settings, Digital Trim (Digital Transmitters)

The advent of “smart” field instruments containing microprocessors has been a great advance for…


Textbook

4-wire “Passive” Versus “Active” Output Transmitters

4-wire “Passive” Versus “Active” Output Transmitters

Some self-powered (4-wire) analog electronic transmitters are designed to behave as electrical loads rather…


Textbook

Rotary-stem Valves

Rotary-stem Valves

A different strategy for controlling the flow of fluid is to insert a rotary element into the flow path.…


Textbook

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…


Textbook

Self-regulating, Integrating, and Runaway Process Characteristics

Self-regulating, Integrating, and Runaway Process Characteristics

Perhaps the most important rule of controller tuning is to know the process before attempting to adjust the…


Textbook

Valve Seat Leakage

Valve Seat Leakage

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


Textbook

AC Motor Braking

AC Motor Braking

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


Textbook

Dampers and Louvres

Dampers and Louvres

A damper (otherwise known as a louvre) is a multi-element flow control device generally used to throttle large…


Textbook

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…


Textbook

Interconnected Generators

Interconnected Generators

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


Textbook

Rotating Phasor in Three-dimensional Form

Rotating Phasor in Three-dimensional Form

The following animation shows a rotating phasor in three-dimensional form. The phasor rotates in a complex…


Textbook

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…


Textbook

Control Valve Sizing

Control Valve Sizing

When control valves operate between fully open and fully shut, they serve much the same purpose in process…


Textbook

Pipe and Pipe Fittings

Pipe and Pipe Fittings

Pipe is a hollow structure designed to provide an enclosed pathway for fluids to flow, usually manufactured…


Textbook