Hollis Explorer User Manual - page 47
OXYGEN SENSOR VOTING
VOTING METHOD
The EXPLORER has a method of automatically removing Oxygen sensor
sensors from the PPO
2
averaging and entering a fail-safe mode when it is
not possible to resolve an accurate PPO
2
reading.
Rules:
1. If a single sensor is below 0.15 bar or above 3.00bar, then it will be
removed from the averaging — a ‘BAD CELL! DO NOT DIVE’ alarm will be
displayed if not diving, or ‘ASCEND! BAD CELL’ if diving.
Diver Action: Ascend on the rebreather
2. If a sensor is less than 7mv then it will be removed from the averaging
— a ‘BAD CELL! DO NOT DIVE’ alarm will be displayed if not diving, or
‘ASCEND! BAD CELL’ if diving.
Diver Action: Ascend on the rebreather
3. If one sensor is +/- 0.2 bar away from the two remaining sensors then it
will be removed from the averaging — a ‘BAD CELL! DO NOT DIVE’ alarm
will be displayed if not diving, or ‘ASCEND! BAD CELL’ if diving.
Diver Action: Ascend on the rebreather
4. If all three cells are removed from the averaging for the same reason
(i.e., all low or all high), then all cells will be used in the averaging (super-
seding rules 1, 2 and 3) — a ‘BAD CELLS! DO NOT DIVE’ alarm will be
displayed if not diving, or ‘ASCEND! BAD CELLS’ if diving.
Diver Action: Ascend on the rebreather unless superseded by rule 7.
5. If the difference between the highest sensor and the lowest is greater
than 0.5bar then the system will inject gas for 1 second out of every 3 as a
fail-safe. This will cause an ASCEND NOW alarm.
Diver Action: Ascend on the rebreather. Rebreather switches to Fail-safe
mode.
6. If the average of all sensors (not removed from the averaging by rules 1,
2, 3 or 4) is greater than 1.6bar when diving then an ASCEND NOW alarm
| 41
3
.1
3