Differential Pressure Sensors: DLHR vs RSC Comparison II
8. Dez. 2018
Both the Honeywell RSC Trustability and AllSensors DLHR differential pressure sensors are very promising candidates for application in state-of-art airspeed sensors. I’m interested in understanding better their relative advantages. So, I’ve added support of the DS18B20 temperature sensor to the UC4H Airspeed node firmware, for independent temperature measurement, and built a setup there both sensors are connected to one and the same pitot-static tube. In this first set of experiments I focused on the zero-pressure offset, with respect to its noise and dependence on temperature variations. For achieving different temperatures I put the setup repeatedly in ambient air, in the fridge, and the freezer.
The RSC sensor datasheet provides an autozero algorithm, so the data were taken first without this being done, which shows the „raw“ offset and then with autozero applied. The autozero procedure is not simply an offset subtraction, so it was interesting to see if it does anything.
In the comparison of the data the different pressure ranges of the two used sensors has to be considered. RSC: ±20 inH2O, DLHR: ±10 inH2O (±20 inH2O correspond to ±5000 Pa).
The noise analysis reproduces the findings I’ve obtained earlier here. The temperature dependent results indicate a significantly better offset stability of the DLHR sensor.
