A Practical Guide to Particle Counting for Drinking Water Treatment - Chapter 9 ppt

... voltage range of a chart recorder or SCADA analog input is 1 to 5 V. A 250 Ω resistor is required to convert a 4 to 20 mA signal into a 1 to 5 V signal. Another benefit of the 4 to 20 mA current ... LLC AUXILIARY FEATURES 97 A second method maintains a constant sample time, but varies the number of particles counted. For instance, on low-concentration filtered...

Ngày tải lên: 18/06/2014, 19:20

... at a time. If a spare is available it can be rotated into service. The maintenance log should be kept up- to- date, and calibration stickers displaying the date of calibration placed on each particle ... practical. 2. Particle Counter Calibration Verification Verifying calibration is an easier and more practical step for the water plant operator. Only a couple of partic...

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... called a voltage comparator input stage. The more complex approach involves analog -to- digital (A/ D) conversion. 1. Voltage Comparator A comparator is simply a small circuit that “compares” an ... typically communicated every minute. The comparator provides a simple way to convert the particle size information from an analog pulse to a digital count value. It is a very...

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... the name implies, a constant “exchange” of data between the particle counter software package and a SCADA software package. The particle counter data are output to a temporary location in the computer’s memory ... gasoline. The data may be transmitted in any type of format, referred to as a “protocol.” These protocols are not standardized, and a lot of effort can be expended...

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... constant, high-quality, and rea- sonably affordable standard for size calibration of particle counters. C. PARTICLE SIZE CALIBRATION To calibrate a particle counter for sizing accuracy, standards covering ... wider acceptance in the drinking water treatment industry. The desire for standards for both instrument accuracy and cross-comparison of data has placed an increa...

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... display are configured with a terminal emulation program via the RS-485 port. The full-scale (20 mA) value can be set to any value up to 9, 999 ,99 9. A sample period and hold time may be programmed as ... E. ANALOG OUTPUTS Met One offers separate particle counter models for serial data and 4 to 20 mA output. The serial data model can provide 4 to 20 mA output data as well....

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... most of the standard SCADA optomux drivers are incomplete and must be modified to accommodate it. Any of the manu- facturers may have developed an interface for a particular SCADA package, so it never ... require a little more effort to clean and maintain, and a particular style of software presentation may be more suited to a given set of operators. Although it is becoming les...

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... Data Broadwell, Mike A practical guide to particle counting for drinking water treatment/ Mike Broadwell. p. cm. Includes index. ISBN 1-5 667 0-3 0 6 -9 (alk. paper) 1. Particle counting (Water treatment ... D.C. A Practical Guide to Mike Broadwell for Particle Counting Drinking Water Treatment © 2001 by CRC Press LLC 6 A PRACTICAL G...

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... Packaged Treatment Plants Packaged treatment plants, as touched on above, are prefabricated plants, which are more cost-effective than ground-up plants for smaller applications. A packaged plant ... 16 A PRACTICAL GUIDE TO PARTICLE COUNTING At the most basic level, particle counters could not be a more natural fit for drinking water treatment. After all, water...

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... PRACTICAL GUIDE TO PARTICLE COUNTING The disadvantage to this approach is that the particle counter data are collected and displayed separately from the other plant data, requiring separate training ... second alternative is the direct interface of the particle counters to SCADA using serial data communications. All count data, as well as status and alarm information, are t...

Ngày tải lên: 18/06/2014, 19:20