JJ-CCR ApS 2017
www.JJ-CCR.com
2017 JJ-CCR ApS – 2.00 / Revision 06
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GF99
This option is to display the actual supersaturation gradient for a pure Bühlmann
(99/99) profile.
With this setting, as long as the NDL time is 0 (you have a decompression
ceiling), the gradient will be displayed instead of the NDL. The number shown is
the percentage of supersaturation. The number is calculated by reference to the
Ambient Pressure Line and the M- Value line. It can be thought of as the current
GF, but it is different in a couple of ways. First, the current GF generates stops
rounded to the nearest 3 metres. So a gradient of 40 may reflect a ceiling of 4.5
metres, but the computer will show a rounded up 6 metres stop.
This number can be used in several ways. First, it can be used to calculate an
aggressive ascent that still has some justification in decompression science. For
expample, if a diver were to lose a significant portion of their gas and needed
to get shallow fast, they could ascend until they reached a gradient of 90, then
stop until it dropped to 80, then ascend to 90 again, etc. that would produce a
Bühlmann-like privile with very little conervatism. In an emergency, that may be
an acceptable risk.
Another use might be to do a slower ascent on a dive to sightsee, but to stay in
the decompression zone by keeping the gradient above 0.
Another use would be to observe the rapidly increasing gradent in the last 3
metres to the surface and slow that ascent.
The controller manufacturer has issued the following remarks:
All of this is based on gradient theory that may be completely false. There is significant disagreement in
the decompression research community about the nature and practice of decompression. Any techniques
described here should be considered experimental, but the concepts may be useful to the advanced diver.
6.16.7
Brightness
Using this menu item it is possible to set
the brightness of the display. Pressing the
right button ”Edit” switches the mode.
Four different modes are available for
selection:
Mode
Description
Auto
The brightness sensor measures the ambient light and automatically adjusts the
brightness of the display.
Low
Permanent minimum brightness
Med
Permanent medium brightness
High
Permanent maximum brightness
Cave
Suitable for very dark environments like caves.
•
The brightness of the display is the major determinant of battery life. Up to 80% of the power consump-
tion is to power the display. When a low battery alert occurs, the display brightness is automatically
reduced to extend battery life.
