ROV Depth Sensor Issues: 30 Bar Incorrect Readings, 1000m Sensor Error Message

Blue Robotics Products Sensors
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Hello, We are experiencing issues with two different depth sensors on our ROV system and are looking for guidance.

30 Bar Depth Sensor(MS5837) Issue:

  • After calibration, the sensor still reads 0 when powered on.
  • Once the ROV is armed, it starts showing fluctuation or incorrect depth values.
  • We’ve repeated calibration, but the issue persists.

1000m Depth Sensor (KellerLD) Issue:

  • We switched to the 1000m depth sensor for testing.
  • This sensor provides accurate and stable depth values.
  • However, we are frequently getting a “Depth sensor error!” message during operation.
  • Despite the error, the displayed depth value remains accurate.

We’d appreciate any help troubleshooting these two issues:

  • Why does the 30 bar sensor show wrong readings even after calibration?
  • What might be causing the “Depth sensor error!” with the 1000m sensor, even though the values look correct?
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Hi @Chandan -
It sounds like your Bar30 may be faulty - please report the issue to further diagnose and potentially obtain a replacement. Was the unit exposed to water for more than 24 hours?

The “Depth sensor error” is often connected to an error in I2C communications. Have you modified any of the wiring, such as extending it, or routed it near particularly electrically noisy systems?
Checking the quality of the signals with an oscilloscope is generally a good idea, and adding a ferrite core to the cable can help - as the Outland Technologies Topside power system manual recommends this part.

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We did some investigating, and found that sometimes the sensor is so stable the autopilot assumes it is broken.

If you analyse an autopilot DataFlash (.bin) log and find the temperature and pressure of BARO1 are completely stable for periods of 2 or more seconds, then this bug is likely your problem, and us increasing the timeout should resolve it.

That said, if your sensor values are noisy then there’s likely some electrical noise on either the power or communication lines that’s causing the readings to fluctuate more than expected, in which case you should refer to @tony-white’s suggestions to diagnose and mitigate the issue :slight_smile:

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