Category Archive: Human Machine Interfaces

Jan
23

Centrifugal Compressor Efficiency – Part 3

Entropy R134a

Part 1 of the centrifugal compressor efficiency series addressed the measurements and parameters that are used to calculate compressor efficiency. In Part 2 of this series we examine how these measurements are used to calculate the enthalpy of the gas stream at the compressor suction and discharged for the refrigerant R134a. This calculation utilized bilinear …

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Jan
16

Centrifugal Compressor Efficiency – Part 2

R134a Thermodynamic Properties

As addressed in Part 1 of the centrifugal compressor efficiency series, the enthalpy of the gas stream at the compressor suction and discharge must be known to determine the compressor efficiency. Also, the isentropic enthalpy must be determined based on the gas stream entropy at the compressor suction and the compressor discharge pressure. These properties …

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Jan
09

Centrifugal Compressor Efficiency – Part 1

Measurements On-line Compressor Efficiency

Centrifugal compressors play an important role within the process industry. In some cases compressor capacity may determine the throughput of a plant. If a compressor is used for refrigeration then any variation in compressor operation may directly impact the temperature control in key unit operations such as flash vessels and exothermic reactors. Also, the compressor …

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Sep
01

Chance of a Lifetime

We have the opportunity to hear the 3 most influential and knowledgeable technical leaders in industry give their assessment of the present state and future of our profession. This will be the first and most likely only time these guys will be sharing their knowledge at the same event, thus covering the complete spectrum of …

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Mar
04

A Calculation so Simple Yet so Powerful

The simple creation of a rate of change signal by passing a process variable with noise suppression (new PV) through a deadtime block with a deadtime equal to the process deadtime to create an old PV and then subtracting the old PV from the new PV creates a powerful delta PV. The PV one deadtime …

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Mar
04

Are We Misleading Our Operators?

The current industry practice for graphic displays may be deceiving our operators, leading to wrong decisions. Our obsession with numbers has resulted in digital displays of process variables that are typically primary process variables (PV) on piping and equipment graphics as the principal method of conveying process understanding. The overriding problem is fundamental and extensive. …

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Feb
08

Virtualization – Real Today, a Reality Tomorrow

Virtualization technology has advanced a lot over the past 10 years. Most IT organizations now make extensive use of virtualization technology to consolidate servers and manage very large numbers of users. Virtualization provides a much improved architecture for isolating applications from hardware changes, securing systems, providing patch management, and improving power management (in large data …

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Dec
23

XY Plots for Operations and Process Analysis

Process visualization and interaction for operations are about to enter the 21st century after being stuck in the 1980s. Emerson and major companies in the process industries and universities through organizations such as the Center for Operator Performance are doing research on how to increase the effectiveness of operators to match the increased capability of …

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Nov
22

Control Loop Foundation Class

The book Control Loop Foundation originated from an internal Emerson training class that I put together for new engineers. The Education Services training center located in Austin, TX provided a class room for this training class. I found this to be an ideal training environment for teaching the class since each class room in the …

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Jan
12

Exceptional Opportunities in Process Control – Virtual Plants

Simulation was such an integral part of my job it is difficult for me to visualize a process control career without models. I was asked to join Engineering Technology (ET) at Monsanto in 1976 because I had developed a dynamic compressor model as the lead Instrument and Electrical engineer for what was the largest Acrylonitrile …

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