Analysis of an ambient temperature influence on the thermal thin-film microsensor

Berlicki, T.M.; Murawski, E.; Osadnik, S.J.; Prociów, E.

doi:10.1016/0924-4247(94)00832-9

Cited by 6 publications

(2 citation statements)

References 4 publications

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“…It should be noted, however, that irrespective of the operating mode employed, the output of a thermal flow sensor will still require compensation for large changes in ambient temperature, due to the temperature dependency of the material properties of the fluid and sensor [6], [12].…”

Section: Ambient-temperature Compensationmentioning

confidence: 99%

“…This may be conveniently done using thermopiles [1]- [4], which, being self-generating transducers, are intrinsically offset free. Their sensitivity, however, is process and temperature dependent, and will therefore contribute to the overall process and temperature dependence of the flow sensor's characteristics [6]. Alternatively, the heating power may be spatially distributed in the sensor such that any flow-induced temperature gradient is cancelled [7], [8].…”

Section: Introductionmentioning

confidence: 99%

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Constant power operation of a two-dimensional flow sensor

Makinwa

Huijsing

2002

IEEE Trans. Instrum. Meas.

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Abstract-To compensate for changes in ambient temperature, thermal flow sensors are usually heated to a constant temperature above ambient temperature. This operating mode, however, requires an extra ambient-temperature sensor. Using a simple model, it is shown that for a two-dimensional thermal flow sensor, similar compensation may be obtained by using a constant heating power, thus eliminating the need for an ambient-temperature sensor. The flow sensor's interface circuitry consists of two thermal sigma-delta modulators that heat the sensor with constant power and dynamically cancel the flow-induced temperature gradient. The modulator's bit-stream outputs are then a digital representation of the heat distribution in the sensor. Wind tunnel tests confirm the validity of the sensor model used and show that both flow speed and direction may be accurately determined from the bit-streams, with errors less than 5% and 3 , respectively, for flow speeds between 1 and 25 m/s.

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Section: Ambient-temperature Compensationmentioning

confidence: 99%