Hollis DG05 User Manual RevA
79
O2 Sensor Polling
The ORI has a method of automatically removing O2 sensor cells from the PO2
averaging. This is called Sensor Polling.
To manually remove a sensor underwater from the main dive screen go to (long
hold bottom right) then <Dvo> then to XDec then O2 appears in the bottom
right corner. Select O2 and then change in the normal way (se page 9). All sensors
(even disabled ones) will still show on the Large PO2 Screen Saver.
Sensor polling is based on a set of rules.
Polling Rules:
1. If a single cell is below 0.15 bar or above 3.00 bar, then it will be disabled, the
system denotes this with a N next to the cell.
2. If after item 1. all 3 cells are disabled for the same fault, then all cells will be re-
enabled – this ensures that if the O2 is very high, or very low and all the cells
agree, the O2 is probably very high or low accordingly
3. If all cells are enabled and have no faults, then each cell is checked to see how
many other cells it is within 0.20 bar of.
a. If all cells are within 0.20 bar of each other, then all cells will be enabled.
b. If two cells are within 0.20 bar of each other and one cell is not, then the cell
that is not within 0.20 bar of the others will be disabled.
c. If no cells are within 0.20 bar of each other, then all cells will be kept enabled.
4. If all 3 cells are disabled with the same fault at this stage, then all will be re-
enabled.
5. All enabled cells are then used in the PO2 averaging. Any cell disabled in these
calculations will have a N shown against it in the O2 sensor screen.
Sensor Polling Examples:
a. Cell 1 = 0.50 bar, cell 2 = 0.60 bar, cell 3 = 0.70 bar. All cells used (rule 3a).
b. Cell 1 = 0.30 bar, cell 2 = 0.60 bar, cell 3 = 0.70 bar. Cells 2 and 3 only used (rule
3 b).
c. Cell 1 = 0.30 bar, cell 2 = 0.60 bar, cell 3 = 0.14 bar. Cells 1 and 2 only used (rule
1).
d. Cell 1 = 0.30 bar, cell 2 = 0.60 bar, cell 3 = 0.90 bar. All cells used as no obvious
fault in any single cell (rule 3c).