Title :
A photopyroelectric measurement device for liquid investigation and monitoring
Author_Institution :
Nat. Inst. for R&D of Isotopic & Mol. Technol., Cluj-Napoca, Romania
Abstract :
A calorimetric measurement device based on the front photopyroelectric (PPE) configuration, consisting in a composite pyroelectric sensor and an irradiation LED, aimed to generate modulated optical excitation is presented. The proposed device is designed for on-field measurements and monitoring of a sample´s thermal effusivity, when the investigated liquid is a semi-infinite layer. The composite PPE sensor is in fact a planar multilayered system, developed in order to have a rigid external surface and to allow picking - up the PPE signal by only accessing one side of the ensemble while the other side can be completely submerged in a liquid. The device is meant to be equipped with an internal preamplifier and an internal controlled current source in order to increase its independence and consequently in order to use it as a remote measurement device. A modulation signal conditioner has also been designed in order to provide a control voltage for the current source which drives the LED. The measurement device along with the modulation signal´s conditioner, with the current source, and with the preamplifier is intended to be used with any embedded control system, provided with a multichannel analog to digital converter and which can deliver two control analog signals. Emphasis will be laid on describing the signal conditioning chain for the excitation source and the signal conditioning chain for the modulation element.
Keywords :
analogue-digital conversion; calorimeters; constant current sources; embedded systems; light emitting diodes; preamplifiers; pyroelectric detectors; calorimetric measurement device; composite pyroelectric sensor; embedded control system; internal controlled current source; internal preamplifier; irradiation LED; modulation signal conditioner; multichannel analog to digital converter; photopyroelectric measurement device; thermal effusivity; Frequency modulation; Light emitting diodes; Liquids; Optical sensors; Thermal sensors; measurement instrumentation; photopyroelectric calorimetry; signal conditioning; thermal diffusivity; thermal effusivity;
Conference_Titel :
Electrical and Power Engineering (EPE), 2014 International Conference and Exposition on
Conference_Location :
Iasi
DOI :
10.1109/ICEPE.2014.6970028