Page 220 - Mechanical Engineers' Handbook (Volume 2)

Mechanical Engineers’ Handbook: Instrumentation, Systems, Controls, and MEMS, Volume 2, Third Edition.

Edited by Myer Kutz

Copyright  2006 by John Wiley & Sons, Inc.

CHAPTER 7
DATA ACQUISITION AND DISPLAY SYSTEMS
Philip C. Milliman
Weyerhaeuser Company
Federal Way, Washington
1 INTRODUCTION 209 6.3 Display of Historical Data 228
2 DATA ACQUISITION 210 7 DATA ANALYSIS 230
7.1 Distributed Systems 230
3 PROCESS DATA ACQUISITION 211 7.2 System Error Analysis 231
3.1 Sampling Interval 211
3.2 Accuracy and Precision of 8 DATA COMMUNICATIONS 231
Data 213 8.1 Serial Communications 231
3.3 Time-Based versus 8.2 Parallel Communications 232
Event-Driven Collection 214 8.3 Networks 232
8.4 OSI Standard 232
4 DATA CONDITIONING 214 8.5 OPC Standard 233
4.1 Simple Linear Fit 215 8.6 Benefits of Standard
4.2 Nonlinear Relationships 215 Communications 234
4.3 Filtering 216
4.4 Compression Techniques 218 9 OTHER DATA ACQUISITION
4.5 More on Sampling and AND DISPLAY TOPICS 234
Compression 220 9.1 Data Chain 234
9.2 Web Programs and Interfaces 235
5 DATA STORAGE 222 9.3 Configuration versus
5.1 In-Memory Storage 222 Implementation 235
5.2 File Storage 224 9.4 Store and Forward 237
5.3 Database Storage 225 9.5 Additional Communications
5.4 Using Third-Party Data Topics 237
Acquisition Systems 226
10 SUMMARY 238
6 DATA DISPLAY AND
REPORTING 226 REFERENCES 238
6.1 Current-Value Inspection 226
6.2 Display of Individual Data MAGAZINES THAT CARRY
Points 227 RELEVANT INFORMATION 238

1 INTRODUCTION
The industry has changed significantly since this chapter was first written in the months
before 1990. The personal computer has become part and parcel of everyday life. Control
systems have become increasingly based on standard systems and interfaces; sensors them-
selves are often based on just smaller versions of the same operating system as large man-
ufacturing systems. This has tended to change the focus from the technology of data
acquisition to the software and systems to support data acquisition.
The trend has been away from requiring the engineer to understand the science of how
sensors work and the lowest levels of data acquisition and more toward the engineer under-
standing the collection, coordination, storage, access, and manipulation of data. With that in

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