The Condensed Handbook of Measurement and Control

Overview

Some measurement and control technologies have evolved rapidlyover the past few years, while others have almost disappeared.Instruments presently in use may become obsolete as newer and moreefficient measurement techniques are introduced. The emergence ofnew techniques is driven by the ongoing need for better quality, bythe increasing cost of materials, by continuous product changes, bytighter environmental requirements, by better accuracies, byimproved plant performance, and by the evolution of themicroprocessor-based devices. These technical developments havemade possible the measurement of variables judged impossible tomeasure only a few decades ago.

Effective measurement requires a solid understanding of theprocess conditions. Selecting the correct measuring and controldevice is sometimes a challenge even for the most seasonedengineers, technicians, and sales personnel.

This handbook provides the tools to enable users to correctlyimplement measuring and control systems, which in many cases is anactivity not well understood and therefore not successfullyimplemented. Given the ever-growing demand for measurement andcontrol applications and the wide range of devices on the market,the user must be able to assess different methods of measurementand control and select the most appropriate one. It is not wise toconsider only one type of measurement or control since each has itsown advantages and disadvantages. The user must compare thedifferent types in terms of which best fits the user’s applicationsince many techniques are available for measuring a parameter (suchas flow, level, etc.). Making the optimum selection involvesconsidering the requirements of the process, the desired degree ofaccuracy, the installation, dependability factors, maintenance, andeconomic factors. Since there is probably no one best method formeasuring a specific variable this guide should help the userdecide which method is more appropriate for the application.

One final note: when describing the function of instrumentationit is important to ensure that we are using uniform terminology.ANSI/ISA-51.1-1979 (R1993), Process Instrumentation Terminology,includes definitions for many of the specialized terms used in theindustrial process industries, such as accuracy, deadband, drift, hysteresis, linearity, repeatability, andreproducibility.

Edition:

3

Published:

01/01/2007

Number of Pages:

470

File Size:

1 file , 4.6 MB