Some Petrel 2 models with analog PPO₂ monitoring require a firmware update to correct offsets to voltage measurements of the O₂ sensor channels. Only Petrel 2 models that shipped from the factory with v29 firmware and include analog PPO₂ monitoring are affected.

Records exist of the proper calibration values, so the calibration can be loaded into affected units by matching the serial number to the recorded data. Shearwater Desktop software can apply these corrections.

This problem can be corrected in firmware by following these steps:

Update the Petrel 2 to firmware v37 or higher.
Install Shearwater Desktop v2.5.6 or higher.
Go to the “Help->Correct O₂ Offset” menu option in Shearwater Desktop.
Follow the on-screen prompts.

If you would like to read more about this issue click here.

Should you have any concerns or problems with performing the correction, please contact Shearwater Research.