Tusa ZEN User manual

DIVE COMPUTER
Owner’s Manual
© 2002 Design, 2008. All rights reserved.
Doc. No.12-2931-r01 (9/15/08)
TUSA QUALITYTUSA QUALITY
Worldwide Contacts:
Tabata USA, Inc. www.tusa.com
Tabata Australia Pty Ltd. www.tusa.com.au
Tabata Europe Corporation B.V. www.tusa.nl
Tabata Mfg. Co. Ltd. www.tusa.net
Tabata Co. Ltd. Japan. www.tusa.net
®

Information that follows amends that presented in the
ZEN Owner's Manual, Doc. No. 12-2931-r01.
PC INTERFACE
The special USB Interface Cable and CD described on pages 16 and 94 of the manual
are components of the TUSA DataLog PC Interface system that is available as an
optional accessory item that can be purchased from your authorized TUSA dealer.
The items are not supplied with the ZEN dive computer.
ZEN
Owner's Manual Addendum
©2002 Design, 2009 Doc. No. 12-2999-r01 (7/28/09)

2
LIMITED TWO-YEAR WARRANTY
For details, refer to the Product Warranty Registration Card provided.
COPYRIGHT NOTICE
This manual is copyrighted, all rights are reserved. It may not, in whole or in part, be copied, photocopied, repro-
duced, translated, or reduced to any electronic medium or machine readable form without prior consent in writing from
Tabata USA, Inc. and Tabata Corp. Ltd. / 2002 Design.
ZEN Owner's Manual, Doc. No. 12-2931
© 2002 Design, 2009
San Leandro, CA USA 94577
TRADEMARK NOTICE
TUSA, the TUSA logo, ZEN, and the ZEN logo, are all registered and unregistered trademarks of Tabata USA and
Tabata Corp. Ltd. All rights are reserved.
PATENT NOTICE
U.S. Patents have been issued, or applied for, to protect the following design features:
Data Sensing and Processing Device (U.S. Patent no. 4,882,678), Ascent Rate Indicator (U.S. Patent no. 5,156,055).
CE
The CE mark is used to mark conformity with the European Union EMC directive 89/336/EEC. TUSA dive instruments
fulfill the required EU directives.
EN 13319 "Diving accessories - Depth gauges and combined depth and time measuring devices - Functional and
safety requirements, test methods" is a European diving depth gauge standard. The ZEN is designed to comply with
this standard.
DECOMPRESSION MODEL
The program within the ZEN simulates the absorption of nitrogen into the body by using a mathematical model. This
model is merely a way to apply a limited set of data to a large range of experiences. The ZEN dive computer model is
based upon the latest research and experiments in decompression theory. Still, using the ZEN, just as using the
Navy (or other) No Decompression Tables, is no guarantee of avoiding decompression sickness, i.e.
“the bends.” Every diver’s physiology is different, and can even vary from day to day. No machine can predict how
your body will react to a particular dive profile.

3
CONTENTS
WARRANTY, NOTICES, DECOMPRESSION MODEL ....................................................................................................2
NOTICE - STORAGE AND INITIAL ACTIVATION ........................................................................................................... 7
FULL LCD ......................................................................................................................................................................... 8
FEATURES AND DISPLAYS ............................................................................................................................................ 9
CONTROL BUTTONS ............................................................................................................................................... 10
OPERATING MODE STRUCTURE ........................................................................................................................... 11
OPERATION AS A DIVE COMPUTER ...................................................................................................................... 12
AUDIBLE ALARM ...................................................................................................................................................... 12
BACKLIGHT .............................................................................................................................................................. 14
POWER SUPPLY ...................................................................................................................................................... 15
PC INTERFACE ......................................................................................................................................................... 16
WATCH FEATURES AND DISPLAYS ............................................................................................................................ 17
LOCAL DEFAULT TIME ............................................................................................................................................ 18
MAIN TIME................................................................................................................................................................. 19
WATCH ALT DISPLAY ............................................................................................................................................... 20
SET MAIN TIME......................................................................................................................................................... 20
ALTERNATE TIME ..................................................................................................................................................... 24
SET WATCH ALTERNATE TIME ............................................................................................................................... 25
WATCH CDT (COUNTDOWN TIMER) ...................................................................................................................... 26
SET WATCH CDT ...................................................................................................................................................... 27
CHRONOGRAPH ...................................................................................................................................................... 28
DAILY ALARM ........................................................................................................................................................... 29
SET DAILY ALARM .................................................................................................................................................... 30
DIVE COMPUTER FEATURES AND DISPLAYS ........................................................................................................... 31
BAR GRAPHS ........................................................................................................................................................... 32
ALPHA / NUMERIC DISPLAYS................................................................................................................................ 34

4
CONTENTS (continued)
DIVE COMPUTER SURFACE MODES .......................................................................................................................... 37
SURFACE MODE ...................................................................................................................................................... 38
NORM SURF MAIN .............................................................................................................................................. 40
NORM SURFALT ................................................................................................................................................. 41
NORM/GAUGE SET MODES .................................................................................................................................... 41
Set FO2 for NORM Nitrox Dives .......................................................................................................................... 42
SET F GROUP (FO2) ................................................................................................................................................ 44
Set FO2 GAS 1..................................................................................................................................................... 44
Set FO2 GAS 2..................................................................................................................................................... 45
Set FO2 50% Default ........................................................................................................................................... 46
SET A GROUP (NORM/GAUG ALARMS) ................................................................................................................ 47
Set Audible Alarm ................................................................................................................................................. 47
Set Depth Alarm ................................................................................................................................................... 48
Set EDT (Elapsed Dive Time) Alarm ................................................................................................................... 49
Set NiBG (Tissue Loading Bar Graph)Alarm....................................................................................................... 50
Set DTR (Dive Time Remaining) Alarm................................................................................................................ 50
Set PO2 Alarm ...................................................................................................................................................... 51
SET U GROUP (UTILITIES) ...................................................................................................................................... 52
Set Wet Activation ................................................................................................................................................ 52
Set Units of Measure ............................................................................................................................................ 53
Set Deep Stop ...................................................................................................................................................... 53
Set Safety Stop ..................................................................................................................................................... 54
Set Conservative Factor ....................................................................................................................................... 54
Set Backlight Duration .......................................................................................................................................... 55
Set Sampling Rate................................................................................................................................................ 56
SERIAL NUMBER ..................................................................................................................................................... 56

5
CONTENTS (continued)
NORM PLAN MODE .................................................................................................................................................. 57
FLY MODE ................................................................................................................................................................. 59
DESAT MODE ............................................................................................................................................................ 60
NORM/GAUG LOG MODE ........................................................................................................................................ 62
HISTORY MODE ........................................................................................................................................................ 65
NORM DIVE MODES ...................................................................................................................................................... 67
NO DECO DIVE TIME REMAINING (NDC) .............................................................................................................. 68
OXYGEN ACCUMULATION ...................................................................................................................................... 69
ASCENT RATE INDICATOR (ASC) .......................................................................................................................... 69
NORM NO DECO DIVE MODE ................................................................................................................................. 70
No Deco Deep Stop .............................................................................................................................................. 72
No Deco Safety Stop ............................................................................................................................................ 74
CAUTIONARY MODES ................................................................................................................................................... 75
DECOMPRESSION ................................................................................................................................................... 76
CONDITIONAL VIOLATION ...................................................................................................................................... 78
DELAYED VIOLATION 1 ........................................................................................................................................... 79
DELAYED VIOLATION 2 ........................................................................................................................................... 80
DELAYED VIOLATION 3 ........................................................................................................................................... 81
VIOLATION GAUGE MODE ...................................................................................................................................... 82
HIGH PO2 .................................................................................................................................................................. 84
HIGH O2 .................................................................................................................................................................... 85
SWITCHING GAS MIXES ............................................................................................................................................... 87
NORM POST DIVE MODES ........................................................................................................................................... 91
FIRST 10 MINUTES ON SURFACE .......................................................................................................................... 92
AFTER 10 MINUTES ON SURFACE ........................................................................................................................ 93
UPLOADING SETTINGS AND DOWNLOADING DATA .......................................................................................... 94

6
CONTENTS (continued)
GAUGE OPERATING MODE ......................................................................................................................................... 95
DIGITAL GAUGE MODE ........................................................................................................................................... 96
FREE DIVE OPERATING MODE ................................................................................................................................... 99
FREE SURFACE MAINANDALT ............................................................................................................................ 100
FREE COUNTDOWN TIMER (CDT) ....................................................................................................................... 102
SET FREE CDT ....................................................................................................................................................... 103
FREE ELAPSED DIVE TIME (EDT) ALARM .......................................................................................................... 105
SET FREE EDT ALARM .......................................................................................................................................... 105
FREE DEPTH ALARMS (DAs) ................................................................................................................................ 106
SET FREE DAs ........................................................................................................................................................ 106
FREE DIVE MAIN ANDALTs ................................................................................................................................... 108
FREE DIVE ALARMS .............................................................................................................................................. 109
REFERENCE................................................................................................................................................................. 113
CARE AND CLEANING ........................................................................................................................................... 114
INSPECTIONS AND SERVICE ............................................................................................................................... 114
BATTERY REPLACEMENT .................................................................................................................................... 115
ALTITUDE SENSING AND ADJUSTMENT ............................................................................................................ 119
CHARTS OF NO DECOMPRESSION LIMITS AT ALTITUDE ................................................................................ 120
CHART OF OXYGEN EXPOSURE LIMITS ............................................................................................................ 121
ERROR (RESET) DURING A DIVE ......................................................................................................................... 122
SPECIFICATIONS ................................................................................................................................................... 123
TUSA INTERNATIONAL .......................................................................................................................................... 130
INSPECTION/ SERVICE RECORD ......................................................................................................................... 131

7
ZEN watch style dive computers are placed in a Deep Sleep mode prior to
being shipped from the factory. The intent is to extend storage life of the Battery
for up to 7 years, before the unit is initially placed in service.
In this mode, Date and Time are updated as they normally would be. However,
they are not displayed. Upon waking the ZEN up, the correct Date and USA
Pacific Time will be displayed and it will be ready to operate with full functions.
To wake the ZEN up from Deep Sleep mode, simultaneously depress the upper/
right (S) and lower/left (A) buttons for 2 to 3 seconds until the display comes full
ON displaying the MAIN TIME screen, then release them.
NOTE: Once the ZEN is brought out of the Deep Sleep mode,
it can only be placed back in it by the factory.
NOTICE
STORAGE and INITIAL ACTIVATION

8
FULL LCD
Components:
a. Mode (M) Button
b. Icon - Log Mode
c. NiBG (Nitrogen Bar Graph)
d. Icon - operating mode
Surface Interval
Plan NDC Time
No Deco Time Remaining
Deco Total Ascent Time
e. O2BG (O2 Bar Graph)
f. Select (S) Button
g. Icon - Stop Time Required
Elapsed Dive Time
h. Icon - Time of Day
i. Icon - Ascend
j. Light (L) Button
k. Icon - Depth/Max Depth
l. ASC (Ascent Rate Indicator)
m. Icon - Low Battery
n. Icon - Stop (Deep, Safety, Deco)
o. Icon - Dive #
p. Icon - Depth
q. Icon - Gas (mix)
r. Advance (A) Button
s. Icon - Descend
t. Icon - Max
u. Icon - Degrees
f
j
q
c
l
b
ug
r
nm
i
d
k
a
h
e
o
p
s
t

9
FEATURES AND DISPLAYS

10
INTRODUCTION
Welcome to TUSA and thank you for choosing the ZEN !
It is extremely important that you read this Owner's Manual in sequence and understand it
completely before attempting to use the ZEN as a dive computer.
Remember that technology is no substitute for common sense, and a dive computer only
provides the person using it with data, not the knowledge to use it.
CONTROL BUTTONS
The ZEN features four Control Buttons that allow you to select mode options and access
specific information. They are also used to enter Settings, activate the Backlight, and
acknowledge the Audible Alarm.
Throughout this manual they will be referred to as the M, S, L, and A buttons.
• Upper/Left - Mode (M) button
• Upper/Right - Select (S) button
• Lower/Right - Light (L) button
• Lower/Left - Advance (A) button
M
A
S
L

11
OPERATING MODE STRUCTURE
Unless it is operating in Dive Computer mode, the ZEN will be
ON in the default WATCH MAIN TIME (home time) mode (Fig.
1), like a standard WATCH, until the Mode is changed.
The M button is used to access other modes that include Alter-
nate Time, Countdown Timer, Chronograph (stop watch/lap
timer), and Daily Alarm. It is also used to revert to the Local
Default Time display and access dive computer modes.
The screens of the Main and Sub modes will remain on display
until a button is pressed to access another screen or Mode,
activate a sequence, or for 2 minutes if no button is pressed.
The Chronograph remains on display as long as it is running
unless another mode is accessed.
When Wet Activation is set On, the ZEN will enter selected Dive
Mode upon descent to 5 FT (feet)/1.5 M (meters) for 5 seconds,
regardless of what operating mode it is in.
WARNING: When Wet Activation is set OFF, the
ZEN must be in Dive Surface Mode (NORM,
GAUG, or FREE) prior to the first dive of a new
series. Commencing a dive while in Watch
modes will not activate Dive Mode unless Wet
Activation is set ON.
Main Sequence
(while at home)
Main Time
Alternate Time
Countdown Timer
Chronograph
Daily Alarm
Alternate Sequence
(at a travel location)
Alternate Time
Main Time (home)
Countdown Timer
Chronograph
Daily Alarm
Fig. 1 - MAIN TIME

12
OPERATION AS A DIVE COMPUTER
The ZEN features 3 Dive Computer (DC) Operating Modes,
NORM (Fig. 2A) which is used for Air and Nitrox dives, GAUG
(Fig. 2B) used for dives in which Nitrogen-Oxygen calculations
are not performed, and FREE (Fig. 2C) used for activities that do
not use SCUBA.
Entering Settings and Plan Mode are only available in NORM
SURF Mode which also allows access to Fly, Desat, Log, and
History Modes.
GAUG Mode only allows access to Fly, Log, and History Modes.
FREE Mode only allows access to specific Free Modes.
AUDIBLE ALARM
Most warning situations that activate the Audible Alarm while
operating in NORM or GAUG Mode cause the ZEN to emit 1
beep per second for 10 seconds, or until the situation is cor-
rected, or it is acknowledged by momentarily pressing and
releasing the S button (less than 2 seconds).
After being acknowledged and the situation corrected, the Alarm
will sound again upon reentry into the warning situation, or entry
into another type of warning situation.
Fig. 2 - DC MODES
2A
2B
2C

13
FREE Dive Mode has its own set of Alarms which emit 3 short beeps either 1 or 3 times
which cannot be acknowledged or set Off.
The Audible will not be active if the Alarm is Set OFF (a group A setting).
Situations that will activate the NORM/GAUG 10 second Alarm include -
• Descent deeper than the Max Depth Set Point selected.
• Dive Time Remaining at the Set Point selected.
• Elapsed Dive Time at the Set Point selected.
• High PO2 of 1.60 ATA or the Set Point selected.
• High O2 of 300 OTU (single or daily exposure).
• Nitrogen Bar Graph at the segment Set Point selected.
• NORM/GAUG Ascent Rate exceeds 60 FPM (18 MPM) when deeper than 60 FT (18
M), or 30 FPM (9 MPM) at 60 FT (18 M) and shallower.
• Entry into Decompression Mode (Deco).
• Conditional Violation (above a required Deco Stop Depth for less than 5 minutes).
• Delayed Violation (above a required Deco Stop Depth for more than 5 minutes).
• Delayed Violation (a Deco Stop Depth greater than 60 FT/18 M is required).
• Delayed Violation (Maximum Operating Depth of 330 FT/100 M is exceeded).
• A Gas Switch would expose the diver to PO2 greater than 1.60 ATA.
• Watch Daily Alarm reaches time set (disabled during Dive Modes).
• Watch Mode Countdown Timer reaches 0:00.

14
A single short beep (which cannot be disabled) is emitted for the following -
• Upon completion of a battery change.
• Change from Delayed to Full Violation 5 minutes after the dive.
3 short beeps (which cannot be disabled) are emitted for the following -
• NORM/GAUG Ascent Rate is 51 to 60 FPM (15.1 to 18 MPM) when deeper than 60
FT (18 M), or 26 to 30 FPM (7.5 to 9 MPM) at 60 FT (18 M) and shallower.
• FREE Dive Elapsed Dive Time Alarm (3 beeps every 30 seconds if set On).
• FREE Dive Depth Alarms 1/2/3 (set sequentially deeper) - each 3 beeps 3 times.
• FREE Dive NiBG Alarm (Caution zone, 4 segments) - 3 beeps 3 times.
• Entry into Deco during a FREE Dive (Permanent Violation) - 3 beeps 3 times.
• Free Dive Mode Countdown Timer reaches 0:00 - each 3 beeps 3 times.
During the following NORM Dive situations, the 10 second continuous tone will be fol-
lowed by a 5 second steady beep that will not turn off when acknowledged -
• Ascending above a required Decompression Ceiling Stop Depth for more than 5
minutes (referred to as a Delayed Violation).
• Decompression requires a Ceiling Stop Depth of 70 FT/21 M or deeper.
• Being on the Surface for 5 minutes after a Conditional Violation (Permanent Violation).
BACKLIGHT
To activate the Backlight - press the L(lower/right) button.
• The Backlight will activate and illuminate the display for button depression time* plus
the user set Duration time of 0, 5, or 10 seconds, for a maximum of 20 seconds.
(*The Backlight will turn Off if the button is held depressed for more than 10 seconds.)
• Press the button again to activate as desired.

15
NOTE: Extensive use of the Backlight reduces
estimated Battery life. Also, the Backlight does
not operate during a Low Battery Condition or
when the ZEN is connected to a PC.
POWER SUPPLY
The ZEN uses (1) 3 volt CR2430 Lithium Battery. Used as a Dive
Computer, the battery should operate normally for 1 year or 300
dive hours if 2 dives are conducted during each dive period.
The ZEN checks battery voltage every 2 minutes on the surface.
• If voltage of the ZEN decreases to the Warning level (2.75
volts), the Battery icon will appear on Surface display
screens (fig. 3a) as an indication that the Battery should be
changed prior to commencing a series of dives.
• If the ZEN's voltage decreases to the Alarm level (2.50
volts), the Battery icon will flash and the message CHG >
bAt will scroll (Fig. 4a) for 5 seconds then operation will
automatically revert to Main Time Mode. The ZEN would
then only operate in Watch modes until the Battery
becomes completely depleted.
• Low Battery conditions are not displayed during dives. If a
Low Battery condition was not displayed prior to starting a
Dive, and a Low Battery Condition occurs during the dive,
there will be sufficient Battery power remaining to maintain
operation for the remainder of that dive. Fig. 4 - LOW BATTERY
ALARM
Fig. 3 - LOW BATTERY
WARNING
a
a

16
PC INTERFACE
Interface with a PC is accomplished by connecting the ZEN to a
PC USB Port using the USB Interface Cable provided. The same
Cable is used for Upload and Download.
The software program is on the CD provided, together with a
USB Driver. The program's Help serves as the user manual and
can be printed for personal use. The Settings Upload program is
used to check the ZEN's existing Settings and for entering Time,
Alarm, and Dive Computer settings into the ZEN. The Data
Download program is used to retrieve Data that was sampled
during dives and stored in the ZEN's memory.
The ZEN checks for an External Access request once every
second while in the Watch Main Time. Checks are not made if
the unit is wet. For a connection to be made, the Interface Cable
is clipped onto the ZEN's Data Port and plugged into a PC USB
Port. To establish the connection, the PC program must be
running. When the connection is made, a PC screen appears
on the ZEN displaying the graphic PC and a 2 minute count-
down or until completion of the Upload or Download operation.
• The ZEN reverts to the Watch Main Time screen after
completion of the Upload or Download operation, or after
the 2 minute countdown.
Fig. 5 - PC
(during upload/download)

17
WATCH
FEATURES AND DISPLAYS

18
LOCAL DEFAULT TIME
Watch Main Time (Fig. 6) is the current Time at your home
location and is normally selected as the Local Default Time.
The normal Watch screen sequence accessed with momentary
presses (< 2 sec each time) of the M(upper/left) button is -
Main Time >> Alternate Time >> Countdown Timer >>
Chronograph >> Daily Alarm
Watch Alternate Time (Fig. 7), identified by the graphic ALt,
set by Hour Differential, is the current Time at a remote travel
location. Upon arrival at the location, Alternate Time can be
interchanged with Main Time to make it the Local Default Time
while visiting the travel location.
The M button will then access the screens in this sequence -
Alternate Time >> Main Time >> Countdown Timer >>
Chronograph >> Daily Alarm
While viewing Alternate Time, depressing the S button for 2
seconds will replace Main Time with Alternate Time that will then
become the Local Default Time until changed.
Fig. 6 - MAIN TIME
Fig. 7 - ALTERNATE TIME

19
While viewing any of the Watch Mode displays, depressing the M button for 2 seconds,
or if no button is pressed for 2 minutes, operation will revert to the Watch Default Time
screen selected.
MAIN TIME, information includes (Fig. 8):
> Nitrogen Bar Graph, if any after NORM/FREE dives.
> O2 Bar Graph, if any after NORM Nitrox dives.
> Daily Alarm icon (clock), if it is set On (Fig. 8a)
> Day of the Week graphic MON (or TUE, WED, THU, FRI, SAT, SUN), or the graphic
WET (if the unit is wet).
> Time of Day (hr:min:sec) with AM (or PM) icon if 12 Hour Format, no icon if 24 Hour.
> Battery icon, if a Low Battery Condition exists.
• Pressing and releasing the M button momentarily and repeatedly (< 2 sec each time)
will step through the Main Watch Modes.
• Depressing the M button for 2 seconds will access Dive
Computer Surface Mode (NORM, GAUG, or FREE).
• Pressing and releasing the A button momentarily (< 2 sec)
will access NORM/GAUG Log and History Modes.
• Depressing the A button for 2 seconds will access the ALT
screen (Elev, Temp, Date) for 5 seconds.
• Pressing and releasing the S button momentarily (< 2 sec)
will silence and acknowledge the Daily Alarm.
• Pressing the L button will activate the Backlight.
• Depressing the A and S buttons simultaneously for 2
seconds will access the SET TIME Menu. Fig. 8 - MAIN TIME
a
MS
AL