2021-07-21
Rev A
Page 20
Shearwater Petrel 1 & 2/Perdix/Perdix AI/NERD 2
Firmware v65 Release Notes
VERSION 65
2019-01-18
CHANGE
The PPO2 limit options have been changed for OC
Tec mode.
Previously, there was an “OC Max PPO2” setting
which only defined when the “High PPO2”
message occurred, regardless of dive phase (e.g.
bottom depth or at deco stop). This confused
many users who, quite reasonably, assumed it was
the “bottom depth” limit and set it to 1.40. This
would result in warnings during deco when the
PPO2 was pushed to the 1.60 range.
The “OC Max PPO2” has now been removed and
replaced with a “OC MOD PPO2” setting. The MOD
setting only applies to the bottom depth phase.
The dive computer automatically switches to using
the “OC Deco PPO2” limit when within 2 stops of
the next deco stop. The “OC Deco PPO2” limit also
sets where predictive deco gas switches occur.
Also, if the current gas has greater than or equal to
80% oxygen fraction, then the deco limit is used,
as the gas is assumed to be a deco gas.
After updating, the “OC MOD PPO2” value is set to
1.40 ATA and the “OC Deco PPO2” is unchanged.
Defaults are:
OC MOD PPO2 = 1.40 [ATA]
OC Deco PPO2 = 1.61 [ATA]
The new behaviour matches that of the Teric.
In semi-closed (SC) mode, only the “OC Deco
PPO2” limit is used for high PPO2 warnings.
(All models)
The “OC MOD PPO2” replaces
“OC Max PPO2” with different
behaviour. Please read the
description to left!
