The reason for posting here ist that I get a constant negative misreading of precisely 39 cm H2O on serial monitor and on Mission Planner quick tab after MS5837-BA02 calibration. I´m aware of the fact that this not the ArduPilot forum. I´m a new user here so I cant upload the arduino script for the moment. I´ll try do do it later.
In brief: Looking at the bluerobotics website and with assistance from the ArduRover forum I managed to connect the bar02 via an arduino script to a NORA+ FC running ArduRover 4.5.3. The MS5873 test script puts out parameters as exspected on serial monitor. The script reads the baros I2C signal and convertes depth measurements (dont need the rest) to a digital PWM signal (50Hz; duration 1.000 to 2.000 mcrs) - a logic level shifter protects the bar02 SCL and SDA lines from 5V I2C signal of the arduino (PIN A4, A5) - everything has common GND - the PWM signal feeds into a GPIO PIN (62) of the NORA+ FC that is defined as a rangefinder with PWM input.
I conected a digital pressure gauge to the bar02 to check for accuracy - which is linear and precise between an external pressure of + 30 to + 800 and above cmH2O.
Now the tricky part that I havent managed to resolve. At ambient pressure (0 mmH2O) on the gauge the bar02 outputs a depth of minus 39 cm H2O on the serial - its 1.600 cm H2O on the rangefinder in Mp.
I increased pressure manually to 40 cm H2O - readings on MP now are +/- 0 mm H2O. But serial depth values remain 39 cm H2O lower than gauge pressure (I calibrated the gauge) across a pressure range of up to 800 cm H20.
Any ideas in this dedicated forum on how to solve the issue calibration misreading or at least modify the script to compensate the issue.