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Benefits of redundant continuous pO2 monitoring?

Discussion in 'Rebreather Diving' started by Jheard89, May 31, 2019.

  1. NAND

    NAND Angel Fish

    # of Dives: 200 - 499
    Location: Germany
    61
    44
    18
    stuartv likes this.
  2. rjack321

    rjack321 Captain

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    8,812
    2,649
    113
    This has happened more than once.
    Ron Akeson was one. There was another in Aus or OZ on an AP unit. Probably more but I haven't been counting.

    Two cells can both fail similarly because cell decline is not necessarily linear. It can be more like cliff when two fall off at the same time. And as long as the two failed cells are within 10% ppO2, most 3 cell voting will consider the 3rd high cell as the erroneous one. Net if you both fall off a cliff at the same time, its not hard for you land within 10% of each other at the bottom.
     
    NAND and stuartv like this.
  3. rjack321

    rjack321 Captain

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    8,812
    2,649
    113
    This is good to get you thinking. But there's actually no actual failure data behind the percentages in a good batch or average batch etc. One key dubious statistic is that 200 out of 1000 sensors fail out of the box. I've been diving CCR for 5 years and been through a little over 20 sensors in that timeframe. I had one fail in the first month and the remainder were retired after 12 months or I had a non-sensor issue that cause me to retired them early (I flooded two different times). Paul admits the percentages are arbitrary but then uses them to support his conclusions which is pretty shaky, especially the "early failure" mode.
     
    NAND, JohnnyC and stuartv like this.

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