Analyze of the environment temperature effect over hydro-energetic buildings resistive transducers

This paper makes a thermal study of a portable temperature measurement device under the influence of environment temperature. The portable device is used to measure sensors placed inside and outside of a hydro-energetic building (dams), where the ambient temperature range is between - 20degCdivide35degC. The self-heating phenomenon of electronics components cumulated with the ambient temperature increases the packaging temperature which affects the device measurement procedure. The usual electronic component that is affected by temperature variation is the resistor and the analog to digital convector, but the most significant error is caused by resistors. A through hole resistor used as a reference, with temperature coefficient of 10ppm/degC and tolerance of 1%, generates a measurement temperature error of 2.5degC - with a 0.1% tolerance the error is reduced by 10 times. Modeling the temperature resistor behavior, the accuracy of measurement device can be less that 0.02degC. To establish the resistor temperature model a thermal imaging analyze is been made and using a microcontroller as a central unit, the temperature error can be eliminate by soft. The PCB components placement and positioning can be also optimized using the thermal image.