12-09-2020 10:57 AM
We can't find constant dependence of pressure in temperature function. Every BMP280 behaves differently. We are using this sensor for altitude measurement. We are using reference sensor and it works quite well when both sensors are calibrated and stays in the same temperature range, but it's unpredictible when temperature changes. We tested 5-6 different BMP280s and can't find dependence between pressure and temperature. We are using compensation functions from datasheet.
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12-16-2020 05:12 AM
Hi,
Need check few question from your attached photo:
12-18-2020 10:59 AM
1. Y-axis unit is Pa, and it represents change of Pa during tests.
2. Offset is not calibrated but it is constant so it doesn't affect this measurement.
3. Pressure is the same for all sensors, temperature change is the same for all sensors.
4. Correct - heating for 0 to 40, colling from 24 to 0.
12-22-2020 08:54 AM
Hi,
The three BMP280 at same pcb board or different, we suggest test at same pcb board to avoid PCB difference.
When we test pressure performance with different temperature, we put barometric sensor at chamber with fixed pressure, then change temperature, log barometric sensor pressure/temperature output.
Best regards.
12-22-2020 12:17 PM
BMPs are on different PCBs - we want to use it on hundreds of different PCBs so testing on the same doesn't make sense.
Still don't have solution for our problem, maybe we will try different sensors.
12-22-2020 02:31 PM
Hi,
BMP280 TCO typical value is ±1.5Pa/k(25℃-40℃), 3σ value(max/min value) larger than 1.5Pa/k. TCO (0℃-25℃)larger than TCO (25℃-40℃). From your test photo, 1st and 2nd BMP280 almost follow this TCO value, 3rd BMP280 influenced by other factor. In order to exclude other interference factor, we suggest test at constant pressure chamber and change temperature.
If you check BMP390 datasheet, TCO is ±0.6Pa/k(25℃-40℃), much better than BMP280. BMP390 also the latest pizeo-resistive pressure sensor from BST. If your product used in outdoors, also need consider humidity performance, high recommend BMP390 as your solution.
Best regards.