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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

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.

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.  

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.


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

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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