Computer-aided monitoring and operation of continuous measuring devices
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Author (Corporation)
Publication date
2004
Typ of student thesis
Course of study
Collections
Type
01A - Journal article
Editors
Editor (Corporation)
Supervisor
Parent work
Water Science and Technology
Special issue
DOI of the original publication
Link
Series
Series number
Volume
50
Issue / Number
11
Pages / Duration
31-39
Patent number
Publisher / Publishing institution
IWA Publishing
Place of publication / Event location
Edition
Version
Programming language
Assignee
Practice partner / Client
Abstract
Extended studies of measuring and control systems in activated sludge plants at EAWAG revealed that the measuring devices remain the weakest point in control applications. To overcome this problem, a software package was developed which analyses and evaluates the residuals between a reference measurement and the sensor and collects the information in a database. The underlying monitoring concept is based on a two-step evaluation of the residuals by means of statistical evaluations using control charts with two different sets of criteria. The first step is a warning phase in which hints on probable errors trigger an increase in the monitoring frequency. In the second step, the alarm phase, the error hypothesis has to be validated and should allow immediate and targeted reactions from the operator. This procedure enables an optimized and flexible monitoring effort combined with an increased probability of early detection of systematic measuring errors. Beside the monitoring concept, information about the measuring device, the performed servicing actions and the responsibilities is stored. Statistical values for the quantitative characterization of the measuring system during operation will be given. They are needed to parameterise controllers or to guarantee the accuracy of the instrument in order to allow reliable calculations of effluent tax. In contrast to other concepts, not only is the measuring device examined under standard conditions, but so is the entire measuring chain from the liquid to be analysed to the value stored in the database of the supervisory system. The knowledge of the response time of the measuring system is then required in order to allow a comparison of the corresponding values.
Keywords
Characterization of measuring devices, On-line analyser, Precision, Trueness, Control, Monitoring
Subject (DDC)
Event
Exhibition start date
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Conference start date
Conference end date
Date of the last check
ISBN
ISSN
0273-1223
1996-9732
1996-9732
Language
English
Created during FHNW affiliation
No
Strategic action fields FHNW
Publication status
Published
Review
Peer review of the complete publication
Open access category
Closed
License
Citation
Rieger, L., Thomann, M., Joss, A., Gujer, W., & Siegrist, H. (2004). Computer-aided monitoring and operation of continuous measuring devices. Water Science and Technology, 50(11), 31–39. https://doi.org/10.2166/wst.2004.0668