Uwatec DC-12 User manual

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SCUBAPRO
A Division of Johnsc:inWorldwideAssociates
1 1326WIiiow Road
Stutteva11t,WI53177
Printed in U.S.A. 3/94 PIN45-027-488
BC-12
DECBIPBEBBIBN
COIPUTEB
OWNER'S
MANUAL

WARNING
READ AND UNDERSTAND THIS MANUAL COMPLETELY BEFORE
USING THE DC-12 DECOMPRESSION COMPUTER.
THIS IS A PRODUCT INFORMATION BOOKLET. THIS IS NOT A
DIVING INSTRUCTION MANUAL, IT DOES NOT ELIMINATE THE
NECESSITY FOR OBTAINING CERTIFIED DIVING INSTRUCTION,
INCLUDING THE PRINCIPLESOF DECOMPRESSION.THE OWNER
IS THEREFORE ADVISED TO OBTAIN SUCH INSTRUCTION, AS
WELL AS A THOROUGH UNDERSTANDING OF THE INFORMA-
TION IN THIS MANUAL, PRIOR TO DIVING WITH THE DC-12
DECOMPRESSION COMPUTER.
© COPYRIGHT 1994 UNDERSEA INDUSTRIES, INC.
All rights reserved.
TABLE OF CONTENTS
Section Page
I Introduction .......................................................................... 1
II Mounting ..............................................................................2
Ill Warnings..............................................................................4
IV Dissolved Gas Theory ......................................................... 9
V Functions ....,.:..................................................................... 1O
VI Display ............................................................................... 12
VII Computer Operation .......................................................... 14
Selecting Programs ........................................................... 14
Master Program Chart ....................................................... 15
1. Sleep Mode .................................................................. 16
2. Surface Mode ............................................................... 17
a. No-Deco Time Scroll .............................................. 17
b. Time Before Flying ................................................. 18
3. History Mode ................................................................ 18
a. Logbook .................................................................. 18
b. Max Depth Recorded............................................. 19
c. Total# Dives Recorded .......................................... 20
d. Total Hours of Operation ........................................ 21
e. Altitude On/Off ........................................................ 22
f. Dive Planner ...........................................................23
4. Dive Mode ....................................................................26
a. Activation ................................................................26
b. Elapsed Dive Time ................................................. 27
c. Current Depth ......................................................... 27
d. Max Depth ..............................................................27

Section Page
4. Dive Mode (cont'd) ......................................................... ..
e. No Decompression Time ........................................ 28
f. Decompression ....................................................... 28
g. DECO and ASC symbol ......................................... 29
h. Graphic Triangle ..................................................... 30
i. Deco Stop Depth and Time .................................... 30
j. Command Arrows ................................................... 30
k. Ceiling ..................................................................... 32
I. Ascent Rate ............................................................ 33
m. Out of Range .......................................................... 34
n. Between Dives ........................................................ 36
o. Repetitive Dives ..................................................... 37
VIII Special Conditions ............................................................. 38
1. High Altitude Diving ...................................................... 38
2. Group Diving ................................................................ 39
3. Chamber Diving or Testing .......................................... 40
4. Error Mode ................................................................... 40
IX Care and Maintenance ...................................................... 41
1. Battery .......................................................................... 41
2. General ......................................................................... 41
X Design Specifications ........................................................ 43
XI Glossary ............................................................................. 44
XII Limited One Year Warranty ............................................... 46
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I. INTRODUCTION
Congratulations on purchasing the DC-12 Decompression Com-
puter. Ifused properly,the DC-12will makeyour divingeasier and safer.
To gainthe maximum benefits fromthe DC-12,andto useitproperlyand
safely, you must read and thoroughly understand this Owner's Manual.
The DC-12 Decompression Computer is a significant advance-
ment in the development of diving computers. It has many remarkable
features.
The heart of the DC-12 is a decompression model developed by
Max H. Hahn, Ph.D., an internationally recognized authority in decom-
pression theory and active diving instructor. Dr. Hahn's latest math-
ematical model is based not only on statistics of decompression sick-
ness (des) symptoms but also on bubble measurements after wet
chamber exposures of human subjects.
The DC-12 Decompression Computer has several pioneering
features:
_.. A decompression model which:
• keeps bubble grades low after 'first' dives
• matches off-gassing speed to the expected bubble grades after
the preceding dive.
• allowstwoelevationranges:Fromsealevelto2,300ft (700m)and
for highaltitudedivingfrom 2,300ft (700m) to 8,200ft(2,500m).
• fights excessive des-risks ofvery deep dives as well as deeper-
than-previous repetitive dives by adding appropriate decom-
pression demands, if such profiles are not avoided.
_.. A unique, easy to read, intuitive display.
_.. A warning display on the DC-12 guides the diver to not exceed a
safe ascent rate or ascend above his decompression ceiling.
_.. The DC-12 battery has a 1Oyear shelf life and has the capacity for
approximately 8 years of active diving ( at 70 dives per year).
1

A The DC-12 has a practical and convenient dive.planner feature.
You can simulate any dive profile in advance, considering any
residual nitrogen retained in memory. The planner runs 12 times
faster than real time so the dive can be simulated quickly.
A If submerged, the DC-12 is automatically switched on by water
sensing contacts. You can manually switch on the instrument by
bridging the contacts with wet fingertips.
A The DC-12 will display the air temperature on the surface.
A Vital information about no-stop decompression times and ascent
rate are displayed inboth digital and graphic format. This makes the
computer easier to use and understand at a glance.
II. MOUNTING
CONSOLE
The DC-12 capsule can be mounted, by means of an adapter into
the Scubapro V.I.P. 3-gauge console for hands free operation. See your
Scubapro dealer for assistance.
NOTE
Ifthe DC-12 is fitted into any other manufacturers console, it must allow
unobstructed water flow to the back of the DC-12 to sense water
pressure.
WRIST MOUNT
For wrist mounting, the DC-12 can be fitted to the Scubapro wrist
strap. To install, the strap should besoaked in hotwater for afew minutes
to make it pliable, then insert the DC-12 into the strap from the bottom.
2
To tighten the strap, push against the strap lock with your thumb
and pull the strap tight. Release the strap lock so it engages one of the
slots in the strap. It may be necessary to retighten the strap at depth
during the dive.
1. push
2. pull
Figure 1a
To loosen, press the strap lockand pull outthe strap enough to slide
the strap over your hand.
1.push
2. pull
Figure 1b
3

111. WARNINGS
TO ENSURE SAFE DIVING AND PROPER USE OF THE DC-12
DECOMPRESSION COMPUTER, THERE ARE VERY IMPORTANT
SAFETY WARNINGS WHlc'i-1MUST BE COMPLETELY UNDER-
STOOD AND FOLLOWED:
1. YOU MUST READ.THIS ENTIRE MANUAL CAREFULLY. Before
you use the DC-12 Decompression Computer, you must be thoroughly
familiar with the functions and operation of the Decompression Com-
puter, and the risks associated with the use of the Decompress!on
Computer. Therefore, before you dive with the DC-12 Decompression
Computer, you must carefully read this entire manuaL Pay close
attention to all instructions -which include all warnings - contained in
this manuaL Make sure you closely follow all of the instructions when
using the DC-12 Decompression Computer. Make sure you under-
stand all of the instructions when using the DC-12 Decompression
Computer. IMPROPER USEOFTHE DC-12 DECOMPRESSION COM-
PUTER CAN RESULT IN SERIOUS INJURY OR DEATH.
2. THE DC-12 DECOMPRESSION COMPUTER DOES NOT AND
CANNOT ELIMINATE THE RISK OF DECOMPRESSION SICKNESS.
No matter how careful you are or what equipment you use, there is a risk
of decompression sickness (also known as "the bends") any time you
dive. The DC-12 Decompression Computer cannot eliminate the risk of
decompression sickness, even when you use the DC-12 Decompres-
sion Computer properly and follow all instructions precisely. The risk of
decompression sickness is part of diving. Before you dive, you must be
prepared to recognize the signs and symptoms of decompression
sickness and know what to do in case of decompression sickness.
DECOMPRESSION SICKNESS CAN RESULT IN SERIOUS INJURY
OR DEATH. DO NOT DIVE UNLESS YOU KNOW AND UNDER-
STAND THE RISKS OF DIVING AND ACCEPT THE RESPONSIBIL-
ITY ASSOCIATED WITH THOSE RISKS.
4
3. THE DC-12 DECOMPRESSION COMPUTER IS TO BE USED
ONLy BY CERTIFIED DIVERS. Safe diving requires training. DO NOT
dive unless you havetaken and passed acertified diver training course.
Such courses are offered by NASDS, NAUI, PADI, 881,YMCA, and
other recognized diver training groups. There are also special courses
available in the use of dive computers. We highly recommend the
completion of such a course prior to using the DC-12 Decompression
Computer.
4. REDUCE RISK BY BEING CONSERVATIVE INYOUR DIVING. No
dive computer or dive table can guarantee against decompression
sickness. TO REDUCE THE RISK OF DECOMPRESSION SICK-
NESS, DIVEWELL WITHIN THE LIMITSESTABLISHED BYTHE DC-
12 DECOMPRESSION COMPUTER. BE CONSERVATIVE WHEN
DIVING.
5. STAY WELL WITHIN SAFETY MARGINS. The DC-12 Decompres-
sion Computer provides the diver with information regarding no-stop
time, ascent rate and wait-to-fly times. These are model limits designed
to protect the majority of divers from experiencing decompression
problems during mostdives. However, notwo peopleareexactly alike,
and studies have shown that certain individuals are moresusceptible to
decompression problems. TO REDUCE THE RISK OF DECOMPRES-
SION SICKNESS, DIVE CONSERVATIVELY. STAY WELL WITHIN
ALL SAFETY MARGINS.
6. DO NOT DESCEND BELOW 100 FEET (30 METERS) ON ANY
DIVE. Even though the DC-12 has the capability of operating to
greater depths, most recognized diving authorities and di~er
certifying agencies recommend that sport divers, even those with
advanced diver training restrict their diving to less than 100 feet.
Sportdivers with limited experience should follow the moreconservative
guideline of 60 feet (18 meters) maximum.
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7. THE DC-12 DECOMPRESSION COMPUTER SHOULD NOT BE
RELIED ON AS THE ONLY MEANS OF PLANNING AND MONITOR-
ING A DIVE. Use backup equipment for each dive and regularly check
backup equipment to ensure that it is operating properly. Buddy diving
provides you with a complete/,set of redundant equipment such as a
second computer, watch, depth gauge or dive tables.
8. WHEN ASCENDING FROM ANY DIVE, MAKE A SAFETY STOP IN
THE 10-30 FOOT (3-9 meter) ZONE FOR AT LEAST 3-5 MINUTES.
Such a precautionary stop will reduce, but not eliminate, the risk of
decompression sickness. This precautionary stop is absolutely essen-
tial for all repetitive dives to 60feet (18 meters) or greater. However, we
strongly recommend a precautionary stop for all dives.
9. IF YOU HAVE DIVED WITHOUT THE DC-12 DECOMPRESSION
COMPUTER DURING THE PRECEDING 24 HOURS, DO NOT BEGIN
USING THE DC-12 DECOMPRESSION COMPUTER. The readings
provided by the DC-12 Decompression Computer will be inaccurate if
the tissues in your body contain nitrogen from a previous dive not
included in the dive history of the DC-12 Decompression Computer.
Therefore, before you begin using the DC-12 Decompression Com-
puter, make sure you have not dived anytime during the previous 24
hours without use of the DC-12 Decompression Computer.
10. IF YOU VIOLATE THE DISPLAY GUIDELINES, SUCH AS EX-
CEEDING THE ASCENT RATE OR IGNORING THE DECOMPRES-
SION STOPS, DO NOT DIVE AGAIN FOR AT LEAST 24 HOURS. The
DC-12 Decompression Computers operate on the assumption that you
have followed the instructions provided by the DC-12. Ifyou violate the
DC-12 guidelines, the information provided by the DC-12 Decompres-
sion Computer will no longer be accurate.
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11. LIMIT REPETITIVE DIVING. There is much still to be learned about
the effects ofrepetitive diving. What is known, however, isthatyou must
be conservative and approach repetitive diving with.extreme caution.
Follow these guidelines with respect to repetitive diving:
a. Limit repetitive dives to 100 feet (30 meters) or shallower.
b. Limit repetitive diving to 3 dives per day.
c. Do not exceed an ascent rate allowed by the DC-12
Decompression Computer:
• ascent rate 50 fVmin (15 m/min) in the
depth range 0-50 ft (0-15 m)
• ascent rate 70 fVmin (21 m/min) in the
depth range 50-100 ft (15-30 m)
• ascent rate 90 fVmin (27 m/min) at
depths below 100 ft (30 m)
d. Always put the deepest part of your dive profile at the
beginning of the dive time and gradually proceed to
shallower depths.
e. Avoid "saw-tooth" diving, that is, bouncing from
shallower to deeper depths within the course of a dive.
f. Remember, deep repetitive dives are for trained,
experienced experts only.
12. MAKE THE FIRST DIVE OF THE DAY THE DEEPEST DIVE.
DURING EACH DIVE, START DEEPER AND WORK SHALLOWER.
This allows nitrogen to outgas from the body as the dive or dives
progress. Diving shallow and then deeper increases the riskof decom-
pression sickness.
13. DO NOT ATTEMPT HIGH ALTITUDE DIVING UNLESS YOU
HAVE RECEIVED SPECIAL TRAINING. There is much still to be
learned about high altitude diving. The DC-12 Decompression Com-
puter is designed for use in high altitude diving. However, be cautious
and conservative about diving in high altitudes. DIVE WELL WITHIN
SAFETY MARGINS.
7

14. DO NOT FLY FOR 24 HOURS AFTER DIVING OR WAIT UNTIL
THE DC-12 DECOMPRESSION COMPUTER INDICATES ITISSAFE.
Do NOT fly until the DC-12 indicates that it is safe to fly. This is indicated
bythe absence of the DO NOT FLYsymbol onthe left side ofthe display
when the unit is turned on. If at all possible, wait 24 hours after the last
dive before flying.
15. ALWAYS DIVE WITH A PARTNER. Not only a must in terms of
safety, buddy diving is also more enjoyable.
16. DO NOT DIVE WITH THE DC-12 IF THE DISPLAY CONTRAST
APPEARS WEAK OR FADED. This indicates that battery is weak
and needs to be returned to Scubapro for service.
17. IF THERE ARE ANY INDICATIONS THAT THE DC-12 DECOM-
PRESSION COMPUTER IS PROVIDING INACCURATE READINGS
OR IS NOT FUNCTIONING PROPERLY IN ANY OTHER FASHION,
IMMEDIATELY STOP YOUR DIVE. Have the DC-12 Decompression
Computer immediately returned to SCUBAPRO directly orthrough your
Authorized SCUBAPRO Dealer. Include an explanation ofthe problems
you experienced. Never dive with equipment you believe may be faulty.
Use common sense.
18. THIS PROGRAM VERSION OF THE DC-12 IS DESIGNED FOR
SCUBA DIVING ONLY, WITH COMPRESSED AIR ONLY AND WILL
NOT PREDICT DECOMPRESSION STATUS CORRECTLY FOR ANY
OTHER GAS MIXTURES.
8
IV. DISSOLVED GAS THEORY
The DC-12 utilizes the dissolved gas theory to predict what hap-
pens in your body during a dive or series of dives. It simulates the
nitrogen absorption during a dive, and nitrogen elimination during
ascent and while on the surface.
Absorption of nitrogen is called in-gassing and occurs as more
nitrogen is forced into body tissues as you dive deeper and/or stay
longer. Elimination of nitrogen is referred to as outgassing and occurs
when the ambient pressure is less than the pressure of nitrogen in
solution within the body tissue.
The DC-12 decompression algorithm computes partial pressures
of dissolved nitrogen in the human body, which is modeled by 9
compartments ('tissues') with half times of approx. 5-700 minutes.
Outgassing is retarded, according to the amount of bubbles to be
expected after the preceding dive(s). Excessive bubble growth during
ascent from very deep dives (inadequately covered by some models)
leads to more conservative decompression. The same applies to
repetitive dives deeper-than-previous as long as bubbles are expected
to be present after the preceding shallower dive.
The following table lists the scrolling single-dive, no-decompres-
sion limits of the DC-12.
DEPTH(ft) 41 51 61 71 80 90 100 110 120 130 139 140
TIME(mins.)99 55 34 25 19 15 13 J11 10 9 8 7
Table 1
Singledive no-decompressiontime limits
9

V. FUNCTIONS
The following functions and readouts are part of the DC-12 Decom-
pression Computer automatic calculations and measurements:
General Functions
1. Self Test
2. Elapsed dive time
3. Program mode indicators
4. Air temperature
5. Current depth
6. Maximum depth
7. Ascent rate warning
8. Warning when flying after diving is not allowed
9. Waiting time before flying
10. Decompression status
11. Dive counter
12. Accumulative dive hour counter
13. Permanent record of maximum depth ever reached
14. REP. indicator for repetitive diving
15. Surface interval log for up to six dives per day
16. Maximum depth and total dive time log for six dives per day
17. Scrolling no-decompression times for 41-149 feet (12-45m)
18. Out-of-range mode
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Decompression Functions
19. Remaining no-decompression time (digital and graphic)
20. Graphic warning when approaching no decompression
time limit.
21. Graphic warning when decompression stops are necessary
22. Decompression stop depth and total ascent time.
23. Shallowest depth allowed (ceiling depth)
24. Graphic warning if ceiling depth is exceeded.
25. Emergency mode with scrolling decompression plan
High Altitude Functions
26. User selected decompression program for high altitude diving to
8,200 feet (2500 meters)
27. Usable as a depth gauge only at altitudes from 8,200 to 13,000
feet (2,500-4,000 meters)
28. Mountain symbol to indicate high altitude decompression mode.
Dive Planning
29. Dive planner for calculating dive profiles or demonstration.
30. Scrolling no-decompression times for dive planning.
11

VI. DISPLAY
The DC-12 display is especially designed to be logical, easy to
understand and intuitive to the user. The display itself is a high contrast
Liquid Crystal Display (LCD). The two opposing diagonal lines printed
across the display divide it into four corners of information, with a large
depth display in the center. Behind these printed diagonals are two bold
LCD arrows that will appear in certain circumstances to advise the diver
to either ascend or descend. The display areas are reserved for the
following information:
Center: depth, temperature, no-deco time graphic
Upper left corner: decompression stop depth.
Upper right corner: total elapsed dive time
Lower right corner: mode indicators
Lower left corner: no deco time or total decompression stop
and ascent time (only when in decompression mode)
Figure 2 shows the maximum potential of what can appear in
each display area. All elements would only be seen during the start up
self-test.
1. No-Decompression/ 11. Minutes or hours indicator
decompression graphic 12. No-deco or total ascent time
2. Elapsed dive time 13. Maximum depth indicator
3. No Fly indicator 14. Total ascent time symbol
4. Decompression indicator 15. Temperature indicator
5. Feet or meters indicator 16. Depth
6. On-sensors 17. Command Arrow (go up)
7. Mode indicators 18. Out of range
8. Repetitive dive indicator 19. Decompression stop depth
9. Command Arrow (go down) 20. Dive number (log book)
10. Wrist strap
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20
19
18
17
16
15
14
13
6
12
11
Figure2
MasterDisplay
1
2
3
4
5
6
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VII. COMPUTER OPERATION
The DC-12 Decompression Computer has four basic modes of
operation:
1. Sleep Mode
2. Surface Mode
3. History Mode
3. Dive Mode
Selecting Programs
Onthe face of the DC-12 aretwo metal contacts (On-Sensors), that
when bridged by moisture (placed in water or touched with moistened
fingertips) will turn the unit on or allow the diver to access the various
program functions.
Each time you activate these On-Sensors for 1-2 seconds, you
move the computer from one program step to the next. Contacting the
sensors for longer periods of time will jump the computer to different
modes as describe in the master program chart. We will describe each
program step by step in the following pages.
To assist you in the Programming Selections, keep these guide-
lines in mind:
1. If the DC-12 is inthe SLEEP MODE (blank display), the computer
can be activated by briefly touching the On-Sensors for 1-2 sec-
onds. The computer will automatically return to the sleep mode to
conserve battery life after 4 minutes 15 seconds if the on-sensors
are dry and the computer is undisturbed.
2. When immersed inwater, the computer,will switch to.and remain in
the dive mode. No other programs may be accessed in the dive
mode, and contact of the on-sensors when in the dive mode will
have no effect.
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SLEEPMODE ~
,.---~-----.1 SEC LBltJ
-------r SURFACESCROLL
4SEC 9 SEC DIVEMODE
~-[I] MAX.DEPTHRECORD [HJ-
SURFACEMODE
TOTAL# DIVES
2 SEC 1 SEC
3 SEC DESCEND 1 SEC
(
PAUSE )
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Chart 1
Masterprogram
PLANNER
OPERATION
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3. When on the surface, in the SURFACE or HISTORY modes the
program being displayed will move one level to another each time
the On-Sensors are activated for 1-2 seconds. Each activation will
sequence you through to the next program step.
4. If the On-Sensors are touched fbr 4 seconds in any mode except
the DIVE PLANNER and DIVE MODE, the computer returns to the
SURFACE MODE and resumes scrolling the No-Decompression
Times. If the On-Sensors are touched for longer than 9 seconds,
the DC-12 will switch to the DIVE MODE. Surface mode program
selections may be resumed by activating the On-Sensors 1-2
seconds.
5. When in the PLAN MODE, touching the on-sensors for 9 seconds
will return the computer to the SURFACE MODE and touching the
sensors for 18 seconds will return it to the DIVE MODE.
6. Once in the DIVE MODE, if no dive is made within 4 minutes and
the On-Sensors are dry, the computer automatically returns to the
SURFACE MODE.
1. Sleep Mode
Ifthe display of the DC-12 appears blank, it is probably inthe Sleep
Mode. If the DC-12 is not actively being used, it will go into the Sleep
Mode after 4 minutes 15seconds. The display will become blank as the
DC-12 conserves battery power. To activate the display, immerse the
DC-12 into the water or touch the On-Sensors (two metal pins beneath
the display) simultaneously with moistened fingers for 1-2seconds. This
activates the computer and rezeroes the depth. Forthis reason, the DC-
12should always be activated onthe surfp.ceprior to diving. Descending
into the water immediately from the sleep mode could cause the zero
point of the depth gauge to be in error.
After activation, the DC-12 display flashes, the computer goes
through a self test and then moves into the surface mode, indicated by
the SURF indicator in the display.
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2. Surface Mode
a. Scrolling No-deco Times
The starting point of the surface program is the Surface Mode
Scroll. This program appears automatically whenever the DC-12 is
activated from the Sleep Mode, or four minutes after exiting the water
from a dive. Based on your saturation level from previous dives, the
Surface Mode Scroll will display the no-deco time limits from 41to 149
feet (12-45 meters) (fig. 3).
Surfaceair
temperature
No-deco
time limit
Graphic Triangle
STOP
DEPTH DIVE
TIME
..-. min
.:..-"-c--+-- Graphic:no-deco
time bars
~ ft DEPTH
1-,--+-- Scrollingdepths
-SURF
HIST
DIVE
Figure3
Scrollingno-decotime limits
The triangular bar graph above the depth display is a graphic represen-
tation of the no-deco time limit. If all four bars are displayed, at least 30
minutes oftime remains. As the time limit decreases, the bars disappear
in order from the largest to smallest. The bars represent from largest to
smallest, 30, 15, 8, and 4 minutes. The number of bars will increase or
decrease in relationship to the digital no-deco time shown in the lower
left corner of the display. This provides the diver with a quick reference
to no-decompression time status. THIS GRAPHIC WILL FLASH AND
CHANGE TO REPRESENT TOTAL DECOMPRESSION TIME RE-
QUIRED IF DECOMPRESSION STOPS ARE NECESSARY. (See also
section 4-h.)
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b. Time Before Flying
The next program step (1-2 second contact) is the wait time before
flying. It is important to know how long it takes before it is safe to fly after
your last dive. The DC-12 will display the abbreviation Flt in the center
display with the number of hours before flying is allowed in the lower left
corner. The DO NOT FLY symbol appears in the upper right of the
display. The REP (repetitive dive) indicator in the lower right appears
whenever there is still tissue saturation remaining from a previous dive
that has not completely cleared (fig. 4).
Hours before
flying is allowed
STOP
DEPTH
NDL
(ASC)
TIME
3. History Mode
DIVE
Tl!'/IE
mm
""""-- Do not fly warning
F-t ~ DEPTH
• ~Ps'V
' !Jh REP. DIVE
Figure 4
Time to fly
Repetitive dive
indicator indicates
tissue saturation
from previous dive
is not yet cleared
a. Dive Logbook and Surface Interval
The next program step (1-2 second contact) switches the program
to the History Mode, note the mode indicator has switched to HIST in the
lower right corner of the display (fig. 5). The DC-12 logbook and dive
recorder stores and allows you to recall the elapsed dive lime, maximum
depth and surface interval for the last six dives made. These dives can
be recalled at any time when in the surface mode until they are
automatically replaced by more recent dives.
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NOTE
DC-12 logbook data is stored only if:
1. The dive time is more than 10 minutes.
2. The dive lime is more than 5 minutes and the maximum
depth is more than 17 feet.
The information is presented in an alternating display. The dive
number (Dive no.1 being the most recent) is displayed with elapsed dive
time, maximum depth and the abbreviation LOG (fig. 5). This is dis-
played for 2 seconds, then the surface interval in hours and tens of
minutes is shown with the abbreviation Int (fig. 6). The logbook begins
with the most recent dive and sequences back through the previous 5
dives each lime the sensors are contacted.
b. Maximum Depth
The next program step (1-2 second contact) displays the maximum
depth ever reached in any dive by the DC-12 (fig. 7). The abbreviation
d-rcd max appears on the display.
Dive#, 1-6
Maximum
depth of dive
Flashing
colon
DEPTH
NDL SURF
(ASC) - HIST
TIME'-------____, DIVE
Figure 5
Logbook display maximum depth
and dive time
Total elapsed
dive time
19

Flashing colon
Surface interval
3 hr: 1o minutes
e. Total Dives
STOP
DEPTH
NDL
(ASC)
TIME
Figure 6
Logbook display-surface interval
in hours and tens of minutes
STOP I
DEPTHd~ DIVE
TIME
min
DEPTH
red
,..._-,L:'..---t-- Maximum
NDL 1, SURF depth ever
(ASC) - HIST recorded
TIME~--------' DIVE
Figure 7
Maximum depth ever reached
The next program step (1-2 second contact) displays the total
number of dives ever made using the DC-12. The abbreviation no red
appears on the display (fig. 8).
20
STOP
DEPTH.,~
red
DIVE
TIME
min
DEPTH
Total number
NDL 3 1---,'---+S-U-RF- of dives made
(ASC) - HIST
TIME~-----~DIVE
Figure 8
Total number of dives made
d. Total Dive Hours
The next program step (1-2 second contact) is the total hours of
active operation of the DC-12. The DC-12 keeps track of the total
number of dive hours accumulated and is shown in the display with the
abbreviation hr red (fig. 9).
STOPh
DEPTH-~ DIVE
TIME
min
DEPTH
red Total hours
2----+--- of operation
NDL SURF
(ASC) - HIST
TIME~-----~DIVE
Figure9
Total hours record
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e. Altitude Program
The next program step (1-2second contact) isthe altitude selection
program. The display will alternate Alt on and Alt off. To select which
program is to be used, simply contact the sensors again when the
appropriate program is shown (on cfroff) to lock in the program, and
advance to the next program step (figs. 10,11). Ifthe Alt on is selected,
the mountain symbol will appear on the display whenever in the dive
mode or when simulating a dive in the planner.
The DC-12 will automatically default to the sea level (Alt off)
program 17 hours after all tissues are cleared. Once the altitude program
is selected and a dive is made, the program cannot be changed again
until the fly time is zero (tissues are cleared).
STOP
DEPTH
~
DIVE
TIME
min
A ~~ DEPTH
NDL - SURF
(ASC) HIST
TIME'-----------' DIVE
Figure 10
Altitude program off
(sea level)
STOP
DEPTH
NDL
(ASC)
TIME
~
A•L
~-
Figure 11
Altitude program on
WARNING
DIVE
TIME
min
DEPTH Altitude
program
symbol
SURF
HIST
DIVE
YOU SHOULD NOT DIVE AT HIGH ALTITUDE UNLESS YOU HAVE
COMPLETED A SPECIAL COURSE IN HIGH ALTITUDE DIVING.
DIVING WITH THIS COMPUTER ABOVE ALTITUDES OF 2,300 FEET
(700 METERS) REQUIRES MANUAL SELECTION OF THE HIGH
ALTITUDE PROGRAM AND KNOWLEDGE ABOUT ITS PROPER
USE. PLEASE REFER TO THE SPECIAL SECTION ON HIGH ALTI-
TUDE DIVING IN THIS MANUAL FOR FURTHER INFORMATION.
22
I
f. Dive Planner
The dive planner isthe next program step (activated by 1-2second
contact) and is displayed with the abbreviation Pin. The Dive Planner
function of the DC-12 allows you to answer the question of "What if?"
This is one of the many outstanding features of the DC-12. Being able
to plan dives and predict decompression requirements for various
possible dives gives you the ability to examine the various dive profiles
for the next dive. The planner forecasts the next dive based on your
current nitrogen saturation level.
NOTE
Ifyou want to skip the Dive Planner, touch the On-Sensors for 9 seconds
after "Pin" is displayed, the computer will switch to the SURFACE
MODE. Touching the OncSensors for 18seconds will return to the DIVE
MODE. (See Chart 1,pg. 15)
When the abbreviation Pin is displayed, (fig. 12)the planner is ready for
activation. Touch the on-sensors again 1-2 seconds. The next display
(fig. 13) appears as the computer would on a real dive except for the
PLAN indicator in lower rightcorner. The display will simulate exactfy as
the real dive would occur.
STOP
~
DIVE
DEPTH TIME
min
D~ DEPTH
NDL V SURF
(ASC) HIST
TIME DIVE
Figure12
Startingpointof
dive plannerdisplay 23

No-deco
time limit
STOP
DEPTH
Flashingcolon
ru /vi
..._ !. • mm Elapsedtime
-==~"--+--Graphic: no-deco
time bars
-
LJt
t.a------l---Current depth
DEPTH
~•..----+---1--- Maximumdepth
NDL ClQ ml.'
~~CJ-1 -lmin
Figure 13
Dive planner display Planmode indicator
1. The Dive Planner can be activated only when Pln is displayed.
2. The DC-12 is now ready to simulate and display any dive profile for
most realistic diving conditions. The computer simulates the dive
based upon your actual tissue saturation.
3. The simulation begins by touching the On-Sensors for two sec-
onds. This starts the simulation by descending in real time at 100
feet per minute (30m/min).
4. To stop the descent and maintain a constant depth, the On-
Sensors must be touched again for 1 second. The elapsed dive
time isaccelerated to 12times faster than realtime, that is 1minute
of dive time will only take 5 seconds.
6. The descent may be resumed any time bytouching the On-Sensors
again for 2 seconds.
7. To ascend, maintain touch with the On-Sensors 3 seconds. The
display will start to descend, then reverse direction and begin
ascending. To stop the ascent again, touch the On-Sensors 1
second. The ascent is made at 50 feet per minute (15m/min).
24
8. Ifthe On-Sensors are touched longer than 9seconds, the computer
turns off the Dive Planner and returns to the surface scroll mode.
9. Ifthe On-Sensors remain touched longer than 18seconds, the DC-
12 switches into the DIVE MODE. This built-in automatic safety
feature assures you the DC-12 will be in the correct Mode when
diving.
10. A light touch with wet fingers is all that is necessary to activate the
On-Sensors.
11. Another much simpler way to judge the time required when touch-
ingthe On-Sensors isto observe the display andjust touch the On-
Sensors until you see the first depth increase or decrease, then
remove your fingers from the Sensors at once.
12. Table 2 summarizes the commands for the dive planner.
Table 2 Commands and Contact Times: Dive Planner
Command On-Sensor Contact Time
Touch 2 seconds
Touch 1 second
Touch 3 seconds
Touch 9 seconds
Descend at 100 ft/min
Pause (maintain depth)
Ascend at 50 ft/min
Surface Mode (scroll)
Dive Mode Touch 18 seconds or longer
IMPORTANT NOTE
The dive planner will not return tothe Sleep Mode automatically until 199
minutes appear inthe elapsed time window. Ifyou havefinished with the
planner, to conserve battery life, touch the on sensors for 9 seconds to
return to surface mode.
25

4. Dive Mode
,.a.Computer Activation
When the DC-12 is immersed in water or the On-Sensors are
touched for more than 9 seconds, the display automatically enters the
Dive Mode (fig. 14).
No-deco
time limit
STOP
DEPTH
Flashing colon
~ .....,__,_,_,,.,,__Elapsed dive time
.=--->.-----+--- Graphic: no-deco
time bars
ran DEPTH
f.a--,---+--- Current depth
( Maximum depth
NDL rl mAH SURF
itcJ_,:lmin ~mi
Figure 14
Display at start of dive
WARNING
Dive mode indicator
YOU SHOULD ALWAYS ACTIVATE THE DC-12 BEFORE ENTERING
THE WATER. The DC-12 requires a 5-second cycle time to conduct a
self-test and rezero the depth gauge. Should you descend below the
surface during those 5 seconds, the zero point used by the computer
may not be at the surface. Your actual depth will be slightly deeper than
what appears on the display. Pre-wet the On-Sensors and wait about 10
seconds near the surface before descencjing.
26
b. Dive Time
The Dive Time appears in the upper right corner of the display.
(fig. 15). The dive time starts when you descend below 4.5 feet (1.3 m)
and stops when you ascend above 4.5 feet.
c. Current Depth
The Current Depth isdisplayed as the large, prominent digits in the
center of the display. A ft or m indicator indicates if the gauge is a feet
or meters version (fig. 15).
NOTE
The maximum depth limitation of the DC-12 is approximately 297 feet
(90 meters). The decompression algorithm is no longer valid below the
depth, and the depth display will freeze at approximately 305 feet
(93 meters) until a shallower depth is reached.
d. Max Depth
The max depth ofthe dive isdisplayed insmaller digits immediately
below the current depth with the abbreviation max (fig. 15).
STOP
DEPTH Elapseddivetime
---"-c--+--- Graphic: no-decotime bars
No-deco
time limit
bars remaining
DEPTH
--...-
~,., ft
• -1---,---+---Current depth
l 5 Maximumdepth
NDL ... m,, SURF
~,~J~'-'--"m=i"'--------'~mi
Figure 15
Sample dive display
after 5 minutesat depth
27

------------------------------·--------------~--~--·--·---------------
e. No Decompression Time
Inthe Dive Mode, the No-Decompression Time appears as a digital
number in the lower left corner of the display. A graphic indication of
relative no-deco time is provided with a series of five black bars
appearing as a triangle above the current depth of the display (fig. 14).
These bars (the triangle) will appear full at the beginning of the dive and
disappear as the no-deco time approaches zero (fig. 15). ·The bars
represent from largest to smallest, 30, 15, 8 and 4 minutes.
Ascending or descending will change the No-Decompression
Times accordingly. By using the No-Decompression Bar as aguide, you
have a quick graphic reference to your relative no-deco time. Ifyou stay
within the displayed no-decompression limits, and never allow all of the
bars to disappear or the no-deco time to reach zero, you can return to
the surface at any time without decompression stops.
WARNING
YOU MUST STAY WITHIN THE NO-DECOMPRESSION LIMITS TO
AVOID POSSIBLE PROBLEMS. Only divers who have completed a
course in advanced decompression diving techniques should go be-
yond the no-decompression limits. Even qualified divers should use
extreme care to prevent decompression problems.
f. Decompression
When you approach the no-decompression limit of 3 minutes, the
graphic no-deco time bars beneath the triangle will have disappeared
down to the last bar. The last bar and top of the triangle will flash to warn
that you are nearing the no-deco time limit (fig. 16). When the no-deco
time limit reaches 1 minute, all bars will have disappeared and only the
top of the triangle remains flashing. Ifyou remain at depth, the no-deco
limit will reach zero time remaining and the display will change to indicate
decompression is required.
28
To avoid decompression, ascend to ashallower depth. The triangle
symbol will stop flashing and additional bars may be added to the
triangle as your depth decreases. The display will significantly change
appearance when decompression is required ( fig. 17 ).
STOP
DEPTH
3 minute
no-deco
time limit
NDL
(ASC)
TIME
,,Qft
~ I
Last graphic bar &
triangle flashes at
DEPTH3 minutes,warning
no-decolimit
SURF
HIST
-•min - DIVE
Figure 16
Dive display
no-decolimit warning
g. DECO and ASC (ascent) Symbol
When a decompression stop is required, the DECO symbol will remain
on continuously and the symbol ASC will appear near the time window
that was previously reserved for no-deco time (fig. 17).The numbers in
the lower left window now indicate total ascent time (ASC). Total
ascent time is the total of the decompression stop times and the time to
travel through the water (at an ascent rate of33 feet per minute) to safely
ascend to the surface. This is aforecast of the minimum amount of time
it should take you to make all of the decompression stops and swim to
the surface.
29

h. Graphic Triangle
The triangular bar graph now represents the total ascent time (total
decompression time plus ascent time) required and will flash con-
tinuously to alert the diver to the tjecompression requirement. The
number of bars in the triangle will increaseas the ascent time and
decompression debt increases. This provides the diver with a quick
reference to decompression status and the flashing will constantly
remind you that you are in the decompression mode.
STOP -o-• lf..
DIVE
DEPTH
C•.• ,,:.:.;._,, uTIME
min
Total ascent
time symbol ,,
ift DEPTH
This is now
~
total ascent time 79
NOL m'" SURF
(ASC) HIST
TIME -DIVE
Figure 17
Dive display
decompression required
i. Deco-Stop Depth
Deco warning
flashes
Decompression
symbol
The current deepest decompression stop depth is indicated in the
upper left of the display. You must stop as close to the decompression
depth as possible to optimize your decompression {fig. 17).
j. Command Arrows
The bold up or down command arrows in the center of the display
will help guide you through your decompression stops. Ifyou ascend too
quickly, the down arrow will appear to indicate you should slow your
ascent. When you reach correct deco-stop depth, both arrows will
appear. This means "stay where you are" (fig. 18). You have reached the
proper decompression stop depth indicated on the display (upper left
30
corner) and must maintain this depth until you have finished your time
at this stop depth. The arrows will remain on when you are in the correct
deco-stop depth range until you have completed your decompression
stop, then the arrows will disappear, and you may ascend tothe new stop
depth. Ifyou violate the deco-stop depth the down arrow will appear, and
flash to warn you to descend immediately (fig. 19a). NEVER RISE
ABOVE THE INDICATED DECO-STOP DEPTH OR IGNORE THE
COMMAND ARROWS.
STOP
Both command DEPTH
arrows on until
it is safe to
ascend to
next stop
Total decompression
and lime required to
safely ascend to
surface
SURF
HIST
'-------==-=='-----------" DIVE
Figure 18
Decompression display
"Stay where you are"
"Down" command --l--'4il' ',.."
arrow flashes if
stop is violated
or ascent is
too fast
Figure 19a
Decompression stop violation
"go down"
Decompression
is required
31

k. Ceiling
During decompression, the stop depth is always displayed in 1O
foot increments (10, 20, 30 etc.). The actual ceiling however is con-
stantly changing depending upon your decompression status. For this
reason, the "stay where you are" arrows may give you considerable
latitude in your actual decompression stop depth. If you do ascend
above the actual ceiling, the down arrow will appear and flash, and the
actua/ceiling depth will appear in the deco-stop depth window until you
descend to this depth. This number is the minimum ceiling depth. You
must descend below this depth to complete decompression. Descend
immediately to this depth, and observe the command arrows (fig. 19b).
STOP ' .... • O:•j DIVE
Minimum DEPTH ~· ,,, -.~. Tl!\IE
ceilingdepth • -~ ✓ ~ ~· mm
is 16feet ••@<••
~
1
-,--------+--- Current
"Down" command i -1 ft,,', DEPTHdepth
arrow flashes if ~~ ~ - ,,,,- is 15'
actual ceiling ~',,, 79 ,,,,,'
is violated (ffc1 r.l'',,,m",,,'' ~Ys'V
TIME !Jmin',,,' • DIVE
Figure 19b
Violation of actual ceiling depth
WARNING
DURING THE DECOMPRESSION PHASE OFTHE DIVE MODE YOU
MUST MONITOR THE DC-12 CONTINUOUSLY TO AVOID MISSING
A DECOMPRESSION STOP. IF YOU MISS A DECOMPRESSION
STOP, THE DOWN ARROW WILL FLASH UNTIL YOU DESCEND TO
THE PROPER DECOMPRESSION DEPTH.
32
WARNING
IFYOU SURFACED AFTER SKIPPING DISPLAYED DECOMPRESSION
STOPS AND TIMES (FOR WHATEVER REASON) WE STRONGLY
RECOMMEND BREATHING PURE OXYGEN, ADMINISTEREDBY A
QUALIFIEDATTENDANT,AND DRINKING ABOUT ONE PINT OF WA-
TERTO PREVENTDEHYDRATION.THISALSOAPPLIESIF(ALTHOUGH
OBEYING ALL DECOMPRESSION RULES) SYMPTOMS OF DCS DE-
VELOP AND IMMEDIATE MEDICAL SUPERVISION ISNOTAVAILABLE.
YOU SHOULD CONSIDER SEEKING QUALIFIED SURFACE RECOM-
PRESSION TREATMENT, ESPECIALLY IF DECOMPRESSION SICK-
NESS SYMPTOMS APPEAR.
WARNING
YOU MUST KEEP IN MIND THAT THE SUSCEPTIBILITY TO
DECOMPRESSIONSICKNESS(DCS)VARIESWIDELYAMONGINDIVIDU-
ALSAND ALSO FROMDAYTO DAY.NEVERTHELESS,IFYOU KEEPTO
THE RULESDISPLAYEDBYYOURDC-12ANDTO CONSERVATIVEPRO-
CEDURES IN GENERAL,THE REMAININGRISK OF DECOMPRESSION
SICKNESS(DCS)ISVERYSMALLALTHOUGHNEVEREXACTLYZERO.
I.Ascent Rate
Ifyou ascend too fast, an arrow pointing downwill flash to warn you
to slow your ascent rate in the same manner as violating a decompres-
sion stop. (See fig. 19) The ascent warning does depend on the depth.
The DC-12 is programmed to allow you to ascend slightly faster from
greater depths and slower from shallower depths.
Ascending slightly faster from deeper depths prevents additional
accumulation of nitrogen during the ascent. The Slow Ascent warning
schedule is as follows:
• ascent rate 50 ft/min (15 m/min) in the
depth range 0-50 ft (0-15 m)
• ascent rate 70 ft/min (21m/min) in the
depth range 50-100 ft (15-30 m)
• ascent rate 90 ft/min (27m/min) at
depths below 100 ft (30 m) 33

=, ,,.-,,-, .=.,,,.-~
m. Out of Range
There areseveral things that will putthe DC-12 into anOut of Range
condition:
1. If decompression is required anc}the total ascent time reaches 49
minutes, the OUT OF RANGE symbol will appear andflash. As long
as it is flashing, the DC-12 is nearing an out of range condition and
can still be used if the required decompression schedule is started
immediately.
2. If the total ascent time reaches 90 minutes, the OUT OF RANGE
symbol will remain on permanently and the computer will remain in
the out of range mode. In the OUT OF RANGE MODE, the DC-12
will no longer compute decompression, but will only operate as a
depth gauge and dive timer. The last required decompression
depths and times before entering out of range will bescrolled onthe
display iri the slop depth and ASC time windows.
3. Ifthe decompression stop is ignored, the DC-12 will go into of OUT
OF RANGE mode.
-34
STOP -..- U[J DIVE
Out of_DE-PT-H+l__c:~ ~~·
range
symbol .... ft DEPTH
~ 80..,
NDL "'l ..d SURF
(ASCl HIST
TIME'-------'l=m=in__ ____c_=DIVE
Figure20
Out of range
4. Ifthe decompression stop depth is greater than 88feet (27 meters),
the DC-12 will go into OUT OF RANGE mode.
5. Any out of range dive will be stored inthe logbook and the OUT OF
RANGE symbol displayed when the dive is recalled.
WARNING
IF THE OUT OF RANGE SYMBOL IS DISPLAYED WHILE DIVING,
YOU MUST IMMEDIATELY GO TO THE DISPLAYED DEPTH FOR
THE DECOMPRESSION TIME INDICATED. IN ANY SITUATION
WHERE DECOMPRESSION HAS BEEN MISSED OR THE OUT OF
RANGE SYMBOL IS STILL DISPLAYED, THERE IS A RISK OF
DECOMPRESSION SICKNESS AND THE DIVER'S CONDITION
SHOULD BE CAREFULLY CHECKED FOR THE NEXT 24 HOURS.
DO NOT MAKE FURTHER DIVES DURING THAT TIME. IMMEDIATE
TREATMENT SHOULD BEADMINISTERED BYQUALIFIED RECOM-
PRESSION SPECIALISTS AND FACILITIES.
35