Poseidon SE7EN User Manual
Appendix 3 Page 100
Figure 2-12.
Test 55 – Service interval check.
Ready to dive
Under normal circumstances the Poseidon SE7EN will successfully complete all Pre-Dive
checks in about three minutes, and a screen will appear on the display that looks like that
shown in Figure 2-14, with a PO
2
value between 0.3 and 0.9 (usually the number is towards
the higher end of this range because the loop is partially filled with oxygen during Tests 49 and
53), a depth of 0, a dive time of 0, and a remaining dive time clock showing 199 minutes.
Figure 2-14.
Ready-to-dive.
At this point,the pre-dive tests are
completed, and the system is ready to dive.
Service interval check (Test 55)
The final test (Test 55; Figure 2-12) is also the simplest. This test merely ensures that the
rebreather unit does not require servicing. Each rebreather unit must be brought to a qualified
Poseidon Service Center at least once every two years, to receive updates and make any
necessary repairs or adjustments. When Test 55 is displayed, the information field will say
“Service in X weeks” which is the number of weeks remaining before servicing will be required.
When this value gets low, return the rebreather to an authorized Poseidon service center for
maintenance. Upon passing Test 55, the pre-dive routine is complete.
Once the service date is due, the diver is prompted to acknowledge with YES or NO that he/she
has understood that service is needed. A grace period of 4 weeks is added.
The service due date can also be seen through the RBConfig PC software.
Prebreathe
Figure 2-13.
Prebreathe.
Open circuit regulator function (Test 54)
After completing Test 53, the information field will have the text “Switch mouthpiece to Open
Circuit” indicating the need change the mouthpiece back to OC mode. When the mouthpiece
is switched, the sentence Breath through the mouthpeice are shown on the screen. This
prompts the diver to test the function of the open-circuit regulator. After inhaling several
breaths from the regulator, the test passes.
Directly after Pre-Dive has completed, the diver will be prompted to perform a prebreathe. This
is shown in the information box in the main screen. When the user switches the mouthpiece to
CC mode, the remaining prebreathe counter will count down from 300 seconds. If the user
switches out of CC then the counter will pause. Once the counter has counted down to zero,
the rig enters ready to dive mode. It will stay in this state for 30 minutes. If the dive is not
started in this time, then it goes back to prebreathe mode. Prebreathe mode is not mandatory
and can be terminated without penalty by starting the dive. 30 minutes after the end of a dive ,
the rig will once again enter prebreathe mode. Note that during prebreathe mode, the rig will fire
the diluent and oxygen solenoids for 2 seconds close to the start of each prebreathe session, if
the diver is not breathing from the loop at this stage the unit may issue an alarm.
The reason for using the solenoids at this stage is that if a diver has turned off either of the cyl-
inders, this will result in a large pressure drop which will prompt the diver to turn the cylinder on.
If a closed cylinder is detected during prebreathe then the appropriate bar graph will flash.
