Am I correct in assuming that such a computer would only be providing a secondary reading of your O2 sensors, and not monitoring pO2 itself? Just trying to get my head round what would happen if one or more of your sensors had malfunctioned but didn't provide a faulty reading (if such a thing is possible?). Would the redundant computer pick this fault up, or would it also continue to read as if everything were fine?
If so, then what are the actual benefits of having a computer that can continuously monitor pO2 (ie a petrel) vs. one that can't (ie a Perdix)?
Basically just trying to decide between buying a Perdix or a Petrel.
You have 2 options for a secondary computer.
First a hard wired or Fisher/DiveCan computer that provides you with a reading of what your actual PO2 is by reading your cells. It won’t control the unit but it will give you accurate deco information based on your actual breathing gas in the loop, etc. The benefit is if your primary poops the bed, you can manually fly the unit based on the info your backup provides.
Second option is a computer that does not read your actual PO2 but you set to your set point manually and it computes your deco based on your depth and the set point you input. You can’t manually control the unit based on this one, since it isn’t reading your loop. That being said, if you maintain your loop close to the setpoint you enter in the backup computer, the deco information on the backup will be really close to the primary, so the deco schedule should be pretty close.
When I’m diving my O2ptima I have a Petrel as the controller and a NERD as a backup. When I’m diving my Kiss units, I have a Petrel or NERD as primary and a Teric or Perdix as the backup. On dives under 90 minutes the primary and backup computers usually are within a few minutes on the deco schedule.
Hope this helps!!