Oxygen sensor Excluded

Problem description:
Oxygen sensor Excluded alarms during the dive, warning for big sensor difference when entering a dive mode or other sensor issues.

Possible causes

• Calibration - old or improper oxygen purity
• Oxygen sensor nearing the end of lifetime
• Condensation on the sensor in sidemount configuration
• Oxygen sensor block oxidation or wiring issue

Step-by-step troubleshooting

• Perform a fresh O2 calibration at the start of a dive day and check your calibration O2 purity setting.
  
  • Do NOT recalibrate between two dives in a single day, humidity from the dive may affect the calibration results.
• If you see a "big difference" warning when entering a dive mode doing multiple dives a day, condensation may be the cause. Breathe the loop for a few moments to check for the sensor response.
• Check your sensor age. Recommended replacement intervals are 12 months from installation and 18 months from the date of manufacture — verify current recommendations in your device documentation or with Divesoft support, as these figures may be updated.
• If your oxygen sensor voltage and values vary even on the surface, then consider trying different oxygen sensor block to rule out any wiring rot issues.
• If your sensor gets excluded only at the bottom or max depth, then it can be a sensor age/linearity issue or a calibration issue. Try swapping the sensor to different position to rule out any wiring issues.
• If a sensor reading seems inconsistent during the dive, perform a Diluent flush: switch to Diluent, take a few breaths to purge the loop, then observe whether all three sensor readings converge to the expected value for the Diluent gas.
• On the surface you can use the Oxygen tester kit to convert the Liberty head into a pressure chamber to test the oxygen sensor linearity.
• If none of the steps above resolved the issue, contact support using the Report Issue feature in the DivesoftApp. Attach the relevant divelogs and syslogs before submitting.