Hi Blue Robotics,
I have a question regarding the performance of the Bar30 pressure/depth sensor. I’ve implemented the sensor as part of a small profiling float. I performed a test where the float performed a cycle in a swimming pool, starting the surface, descending to the bottom, and rising again, repeating four times. The test duration was 8 minute and in that time, the water surface ‘height’ changes 0.45 m (45 mBar), a rate of approximately 0.05 m/min (5 mBar/min). Ultimately, I’d like to perform depth control based on the Bar30 pressure sensor, but this amount of drift may be problematic.
From reading the TE Sensor Datasheet, and this forum discussion, I understand that the absolute pressure may be off by ±50 mBar or ±0.5 m (for these testing depths).
I did perform a benchtop test to assess longer term drift, but the test was not performed in water (I’ll probably be setting up this test later this week). There was a (nonlinear, tapering off towards end of test) drift from 0.03 m (1016 mBar) to 0.18 m (1032 mBar) over 50 minutes, average rate of 3.2mBar/10min. Quite a bit smaller than the pool test, but still considerable.
I noticed you did have a case of a faulty sensor, but the drift exhibited there was quite a bit more than what I’m seeing. Given the ‘long-term’ stability advertised by TE is ±30 mbar/year, even the observed drift seems strange.
Any advice would be much appreciated.