Page 19
Doc. 13301-Tec-RevB (2022-05-25)
Technical Modes
Operating Instructions
SurfGF
The surfacing gradient
factor expected if the diver
instantaneously surfaced�
SurfGF colour is based on the current GF (GF99)� If
the current GF is greater than GF High, SurfGF will be
displayed in
Yellow
� If the current gradient factor is
greater than 100%, SurfGF will be displayed in
Red.
Ceiling
The current decompression ceiling
not rounded to the next deeper
stop increment� (i�e� not a multiple
of 10ft or 3m)
@+5
“At plus 5” is the TTS if remaining
at the current depth for 5 more
minutes� This can be used as a
measure of how fast you are on-
gassing or off-gassing�
Δ
+5
The predicted change in TTS if you
were to stay at the current depth
for 5 more minutes�
A positive “Delta plus 5” indicates that you are on-
gassing the leading tissue while a negative number
indicates that you are off-gassing the leading tissue�
Battery
The Perdix 2’s battery voltage�
Displays in
Yellow
when the battery
is low and needs replacement�
Displays in
Flashing Red
when the
battery is critically low and must be
replaced as soon as possible� Also
shows battery type�
Gradient Factor
The deco conservatism value when
the deco model is set to GF� The low
and high gradient factors control
the conservatism of the Bühlmann
GF algorithm� See “Clearing up the
Confusion About Deep Stops” by
Erik Baker for more information�
VPM-B (and VPM-BG)
The deco conservatism value when
the deco model is set to VPM-B�
If the deco model is VPM-B/GFS,
also displays the gradient factor for
surfacing�
GF99
The current gradient factor as a
percentage (i�e� super-saturation
percent gradient)
0% means the leading tissue super-saturation is equal
to ambient pressure� Displays “On Gas” when tissue
tension is less than the inspired inert gas pressure�
100% means the leading tissue super-saturation is
equal to the original M-Value limit in the Bühlmann
ZHL-16C model�
GF99 is displayed in
Yellow
when the current gradient
factor modified M-Value (GF High) is exceeded�
GF99 is displayed in
Red
when 100% (un-modified
M-Value) is exceeded�
3
:
00
15 62 0
SurGF
.
7
:
:
GF99
%
CEIL
%
3
:
00
20 12
GF
.
7
:
:
TEMP
°C
CNS
30/70
3
:
00
15 62 0
SurGF
.
7
:
:
GF99
%
CEIL
%
+3
VPM-B
+3/90
VPM-BG
m
min
Δ
+5
+8
@+5
20
CEIL
8
SURFACE
m
min
Δ
+5
+8
@+5
20
CEIL
26
SURFACE
m
min
Δ
+5
+8
@+5
20
CEIL
26
SURFACE
3.99
V
BATTERY
3.7V
LiIon