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Process Variable Analyzer

turning routine data into actionable information

The Process Data Analyzer is virtual meaning it's not really there.  And yet, the figure below shows a box.  To clarify, the box is merely a way to transmit to the PC a signal that is already there.  In the case chosen, there are two temperature probes, a thermocouple and an RTD, the former inside an insulated cup, the latter on a steel ring supporting the cup.  The cup is meant to represent a process tank and the steel ring the outside support of the tank

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The conventional interpretation is that the collected data is merely logged.  But a problem or a set of problems can impose an analytical question on the logged data, transforming  a dumb logger, via an algorithm, into an analyzer.

 

For example, suppose you wanted to measure and control the flow of heat out of the tank.  A really simple example is shown below.

The "virtual analyzer" and cup are accompanied by the electronics needed to support the thermocouple and RTD.

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To emphasize that the hardware called the virtual analyzer really is nothing more than a data logger, two more sets of contacts are shown: one measuring a battery voltage and the other, spade lugs, open and ready to be used.

After addition of hot water to the test cup, the thermocouple, data base 1 (dbone) trace rises quickly to 80C and cools gradually.  

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Meanwhile, the RTD registers a gentle, but noticeable rise of 5C over that time interval, clearly showing that the insulation is not as good as expected.

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This thermal response trace is called the "Process Batch Fingerprint", PBF, for this cup/support test system measured with this virtual analyzer.

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In practical situations, the logged data is the set of variables arising from a process batch.  These include temperature, but also motor frequencies, motor power, pH, vacuum.  Each of these parameters has a trace of value versus time.  These traces represent PBFs for these parameters.

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