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Abstract and Manuscript Management System - Abstract Detail |
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| Speaker: | Janice Bennett |
| Title: | Catching the drift: Adventures in measuring humidity |
| Topic Group: | Humidity |
| E-mail: | jbennett@veriteq.com |
| Co-Authors: | |
| Abstract: |
While the capabilities of capacitive Relative Humidity sensors have been well described and documented, the electronic circuits used to measure these sensors, and how they impact a measuring device’s accuracy has not. RH remains one of the single hardest parameters to measure accurately, although metrology has made incredible advances in measuring temperature, the affect of RH on temperature is still underemphasized in design of industrial sensors. The Life Sciences and Pharmaceutical industries, which both rely heavily on industrial measuring devices for many critical processes, are subsequently left to use measuring devices that have substandard humidity measuring capacities, particularly over a wide operating range. This paper first describes what is required in overcoming the problems associated with the traditional circuitry of RH sensors. The paper further describes the testing processes undertaken by Veriteq Instruments over a number of years wherein a variety of measuring circuits/systems were evaluated. There are several problems that are unique to an electronic in situ humidity measuring device which must operate in a wide-range environment: <1% to > 95% RH and -40°C to +85°C. Over several years of testing different approaches on how to increase the level of accuracy that could be achieved in measuring RH over a wide operating range, a familiar measurement approach was finally created. This approach adapted a small-sized very low power system. The resulting RH measuring method has changed industry standards on the accuracy specifications of RH sensors. |
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