User manual

Poseidon MKVI User Manual Chapter 2 Page 42
Open circuit mouthpiece position (test 43)
Test 43 (mouthpiece OC position test) is automatically passed provided the mouthpiece was
left in the OC position following the previous steps. If, for some reason, the mouthpiece is not
in the OC position when Test 43 appears on the screen, the mouthpiece vibrator will activate
along with the HUD and battery LEDs and audio alarm. The letters “OC” will appear in the
upper-left corner of the LCD screen and, along with a low frequency tone and the “Open-Cir-
cuit” icon (diver with bubbles), will ash until the mouthpiece switch is placed in the OC position
(Figure 2-7). The system allows the diver up to two minutes to make this switch. The “Open-
Circuit” icon will continue to display on the LCD until Test 50, when the mouthpiece needs to
be switched to the closed-circuit (CC) position.
If the mouthpiece appears to be in the open-circuit position, but Test 43 does not pass, then make
sure that the mouthpiece switch is fully in the OC position. If the test still will not pass, then
make sure the HUD is positioned correctly on the mouthpiece, and is not twisted or otherwise
moved from its proper position. If no amount of repositioning of the mouthpiece lever or HUD
allows the system to pass Test 43, then contact an authorized Poseidon Service Center.
Fig ur e 2-7.
Test 43 (Mouthpiece in OC position),
displaying Open-Circuit icon to indicate
that the mouthpiece must be placed in
the Open-Circuit position.
Tissue tension (test 40)
As discussed in Chapter 1, the Poseidon MKVI stores decompression data in two places: the
battery, and the main backpack computer. This allows a diver to switch to a spare battery while
maintaining decompression in the rebreather unit, or switch rebreather units and transfer the
active decompression data with the battery.
Test 40 (Tissue Tension Test) compares the stored decompression information in both the
battery and in the main backpack computer. If the two decompression states do not exactly
match on a compartment-for-compartment level test 40 will fail soft. Failure of this test is a
notication to the diver that the system has detected this discrepancy between the two sets of
decompression data. This will be displayed to the diver by that ‘dECO rESEt’ scrolls in the PO
2
eld or any other hard failure by a failure code.
IMPORTANT:
It is always best to make sure that the decompression data is
consistent between the battery and the rebreather. Conrming
a deco reset in the pre-dive routine following a soft failure of Test
40 will likely lead to reduced allowable dive time on the next dive
(depending on thenature of the data discrepancy).
If the battery switch is intentional the diver can conrm this by the wet switch wet/dry sequence,
the system will resolve the decompression difference by selecting the most conservative value
for each compartment of the decompression algorithm. If it is non-intentional re-start the
pre-dive test with the correct battery installed.
Canister Good conrmation (test 41)
Test 41 requires the user to conrm by the wet switch wet/dry sequence that:
A
They have a canister installed
B It contains sufcient unused absorbent to complete the dive.
This becomes visible on the display by that the word ‘CAniStEr ‘ is scrolled
through the PO
2
eld. NOTE; This test is not automatic and is intended as a reminder for the
diver. By conrming test 41 the diver acknowledges that he/she has installed a canister prior to
powering up the MKVI.
IMPORTANT:
Do NOT adjust the mouthpiece position again after completing
Test 43, until instructed to do so at Test 50. In order to complete
Test 49 (positive pressure loop test) successfully, the mouthpiece
must remain in the Open-Circuit (OC) position.