Honeywell Minitrend QX, Руководство пользователя

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43-TV-25-30 Iss.6 GLO Aug 07 UK 293
Appendix F: Fuzzy Logging
What is Fuzzy Logging?
Fuzzy Logging
is a real time Data Compression technique. Patent no. US 6,405,155 B2 ,
developed at Honeywell as an alternative to the more standard methods of recording data.
Paperless Recorders are primarily used for exception recording. They spend most of their
life trending and recording straight lines. Fuzzy Logging has been developed to improve the
efficiency of data storage, and is particularly effective in exception recording examples
where normal operation consists of generally static inputs.
Fuzzy Logging looks for straight lines in the data stream, in real time, whether they are hor-
izontal, climbing or descending. A straight line made up of say 10 points can be equally well
represented by 2 points, one at either end, the other 8 points are redundant. Fuzzy logging
works by creating straight lines in the data and discarding redundant points.
What’s it for?
…… To help the user in the trade off between
Scan Rate , Disk capacity and Recording
Time, after all the ‘Pie’ is only so big.
Fuzzy Logging has been developed to help
maximise all three sections, in effect increas-
ing the size of the ‘Pie’.
The result is a technique that delivers a host
of real world benefits over the more traditional
recording methods.
1. Disks take longer to fill – changed less frequently, less site visits.
2. Faster scan rates can be used for any given disk size – giving greater resolution on the
process.
3. Recording time can be extended.
4. Less hard disk memory required for archiving on the PC.
5. Quicker graphing of data.
6. Smaller data files for remote collection.
How does it work?
Fuzzy Logging does not log data points that form part of a straight line.
The technique is best illustrated by the diagram below:
The Recording 'Pie'.
Scan Rate Storage Capacity
Recording Period