Absolute Pressure Error

Blue Robotics Software ArduSub
6

I think I’ve managed to figure this out:

  1. “depth sensor is not connected” is reliant on ap.depth_sensor_present
  2. which is conditional on the sensor being a water type sensor
  3. which is currently only set for Keller LD and MS5867 sensors

Part 3 there will partly be the case because those are the only sensor types we’ve tested with for use under water, but in the case of the MS5611 specifically is also potentially important because that’s a sensor that’s already used internally in the Pixhawk, and registering the internal sensor as a measure of the water pressure is a really bad idea.

Given you seemingly have an MS5611 sensor that you want to use in the water (I’m assuming you’ve already confirmed that’s a viable use-case of your sensor), you could make a custom firmware build* that just also sets that as a water type sensor (it will be in the same file as the MS5687 part). Note that you’ll need to be extra careful, because if the sensor fails and MS5611 sensors are registered for water use then the firmware will likely fall back to using the internal sensor, which could be quite confusing since it will be reporting supposedly valid but completely illogical depth values.

*Note that ArduSub-stable is currently a bit problematic, and we’re planning to make ArduSub 4.1 the new stable quite soon, so it may be better to use ArduSub-beta instead for the moment.