Tusa IQ-850 DC-Sapience User manual

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OPERATINGMANUAL
DIVECOMPUTER
IQ-850

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User Manual Contents
IQ-850 Flow Chart and Information 2
1. Introduction 8
2. Key Features 8
3. Common Sense Warnings 8
4. Accessing Display Modes 11
5. Time Mode 12
6. Dive Set Mode 14
7. Dive Plan Mode 16
8. Log Profile Mode/Warnings 18
9. History Mode 23
10. PC Transfer Mode 24
11. Time Set Mode 25
12. Dive Mode 26
13. Warning Screens 31
14. Altitude Setting 36
15. Battery Level Icon 38
16. Battery Replacement 38
17. Units of Measurement 39
18. General Handling 39
19. Warranty 40
22. Technical Specications 44

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IQ-850 Flow Chart

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IQ-850 Flow Chart cont.

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IQ-850 Flow Chart cont.

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IQ-850 Flow Chart cont.

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IQ-850 Flow Chart cont.

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IQ-850 Flow Chart cont.

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1. Introduction
Congratulations on your choice of the TUSA IQ-850 Dive Computer.
The IQ-850 is a compact and sophisticated dive instrument that will
give you reliable, trouble free performance, dive after dive.
The information in this manual has been developed for your safety.
Please read and understand this manual completely before using
your new TUSA dive computer.
2. Key Features
Among the IQ-850’s key features:
• Air, Nitrox, Gauge and Time Operating modes
• Dot matrix tissue compartment/message display window
• Vibration, audible, and visual alarms
• 2 mix switching feature: Mix 1(Air, 21-99%), Mix 2(21-99%)
• 25 hour/dive log memory, PC downloadable
• Advanced user safety settings and alarms
• Manual or Water activation
• Large alphanumeric and backlit display
• User replaceable battery (Battery: CR2032)
3. Common Sense Warnings
As is true of every piece of diving equipment, including all dive
computers, the IQ-850’s abilities are not limitless. There are certain
limitations and restrictions of which you must be aware, and certain
precautions you must take when using the IQ-850.

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The IQ-850 is designed for use by certied, recreational divers
who have maintained a sufcient level of knowledge and skill
prociency through a combination of formal training, ongoing study
and experience. It is not intended for use by persons who lack
the qualications, and thus may not be able to identify, assess,
and manage the risks scuba diving entails. Use of the IQ-850 in
conjunction with Enriched Air Nitrox (EANx) further requires that the
diver be trained and certied for Nitrox diving.
The IQ-850 is not intended for use by commercial, military or
technical divers whose activities may take them beyond the
commonly accepted depth limits for recreational diving.
The IQ-850 is designed for use by divers breathing either normal
compressed air or Enriched Air Nitrox (EANx) mixtures whose fraction
of Oxygen falls within a range of 22 to 99 percent.
Although the IQ-850 is capable of calculating decompression stop
requirements, this ability is provided as a safety feature only, should
a diver accidentally exceed the No-Decompression Limits (NDLs).
Dives requiring mandatory stage decompression carry substantially
greater risk than dives made well within no-decompression limits.
Decompression diving is widely believed to entail substantially
greater risk of decompression illness than dives made well within
the No-Decompression Limits (NDL). The IQ-850 provides
decompression stop information solely as a contingency in case
divers accidentally exceed the No-Decompression Limits. It is not
designed or intended for use as a tool to plan or execute dives
that participants know will entail mandatory decompression.
WARNINGS
Before using the IQ-850, it is extremely important you read the
following points as well as similar warning and caution notices
that appear throughout this manual. Failure to do so could result
in damage to or loss of equipment, serious personal injury, or
death.

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The IQ-850 is designed to be used by only one diver at a time. Divers
should not share a single IQ-850, or any dive computer, on the same
dive. Additionally, no diver should lend his or her IQ-850 to anyone else
until it calculates that no measurable residual nitrogen remains after
previous dives, and displays neither the “Desaturation Time” nor “No Fly”
indicators while in Surface Mode. Further, no diver should use his or her
IQ-850 for repetitive dives unless that same IQ-850 has accompanied
him or her on all previous dives in the same repetitive dive series.
Neither the IQ-850, nor any other dive computer presently available,
physically measures the amount of nitrogen present in body tissues, or
the rate at which this nitrogen is being absorbed or released. Instead,
the IQ-850 monitors depth and time, and uses this data to work a
mathematical formula designed to emulate how individuals in good
general health and whose physical characteristics do not place them
among those at higher risk of decompression illness are assumed
to absorb and release nitrogen from body tissues. Thus, the IQ-850
cannot compensate for factors such as age, obesity, dehydration, cold
or exertion, which experts believe place divers at greater risk of DCI. If
these, or similar factors apply to you, use the IQ-850, and any other dive
computer or dive table, with even greater caution.
Experts still know surprisingly little regarding the exact nature and causes
of decompression illness (also known as decompression sickness, DCI,
or DCS). Susceptibility to DCI may vary substantially from person to
person and from day to day. Neither the IQ-850, nor any dive computer
or table, can guarantee that you will not suffer decompression illness.
Even though you use these items correctly, you may still suffer DCI. Do
not rely on the IQ-850 as your sole means of avoiding decompression
sickness.
WARNINGS

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4. Accessing Display Modes
There are some display modes that the IQ-850 enters and/or exits
automatically. For example, by taking the IQ-850 underwater, you
automatically activate its Dive Mode. Upon surfacing your IQ-850
will automatically enter Time Mode.
To access other modes, you may need to push one of the three
large buttons on the sides of the IQ-850. These are the A, B, and C
buttons. (Fig. 1)
You will nd these buttons easy to use. In some instances, you may
need to press a button once and release it to achieve the desired
result. In other instances, you may need to hold the button down
until you get the result you wish. This manual will outline which
procedure to follow for each mode or task.
Throughout this manual display icons that blink are shown
surrounded by gray bars.
Experts recommend divers wait at least 24 hours following any dive
before ying in an aircraft or driving to altitude. Failure to allow
sufcient surface interval before doing so may substantially
increase the risk of Decompression Illness (DCI).
Do not plan dives to depths deeper than those for which the IQ-850 is
capable of displaying an available No-Decompression Limit. Doing so
could cause you to exceed the No-Decompression Limits or limiting
PO2 of 1.6 bar, which may in turn substantially increase your risk of
decompression illness or CNS Oxygen Toxicity and can lead to serious
personal injury or death.
C
B
Figure 1
E
A

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5. Time Mode
• Current time: This is the current time of day.
• Current date: This is the current date.
• Current weekday: This is the current day of the week.
• Battery indicator Icon: This displays low battery voltage. (not
shown unless necessary)
• PGT (Pressure Gas in Tissue) graph: Indicates the level of Nitrogen
in the twelve tissue compartments. The higher the bar displayed
the greater the nitrogen level in the tissue. +/- denotes off or on-gassing.
• OLI (Oxygen Limited Indicator) graph: This indicates the level of
Oxygen in the diver's body with eight level indicators.
• Nitrox Icon: This Icon is ON when NITROX has been selected.
• Desaturation time (DESAT): This indicates the time remaining until
the body’s internal nitrogen is desaturated. The DESAT is also
displayed if PGT occurs because of a change in the altitude rank.
Time mode is the IQ-850’s default mode. In this mode the screen
displays a minimum of the current date and time of day. Within 24
hours of surfacing from a dive, the IQ-850 will display additional
information while in Time Mode. A description of the screens is
shown below. (Fig. 2,3)
Normal Mode Post Dive Mode
Figure 2
Figure 3
PGT Display Graph

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Warning
Experts recommend divers wait at least 24 hours following
any dive before ying in an aircraft or driving to altitude.
Failure to allow sufcient surface interval before doing so
may substantially increase the risk of Decompression Illness
(DCI).
• Surface time (SURF.T): This is the surface interval time after a
dive. The timer is started from when the depth shown in Dive
mode reaches 5 feet (1.4m) or less. If the depth changes back to
5 feet (1.4m) or more in less than 10 minutes, the previous dive
is continued. Surface time is continued for 48 hours. After that,
surface time is turned off.
• Mode: This display shows the computer in Time mode.
• Don’t Fly "Airplane" Icon: While the desaturation time is calculated
this icon is displayed during Time Mode. When the computer has
nished calculating desaturation time this Icon is turned off.
Prior to a dive
The letters correspond to the buttons of the IQ-850 shown in Figure 1.
• A button: Press this button to scroll to next mode.
• A button held for 2-3 seconds: Reverts to time mode.
• B button held down: Time display and backlight comes on.
• C button: Activates backlight.
• B+C button: Activates alarm sound or vibration test.
• E button: Touch this switch and metal housing to switch to dive
mode.
Operation of buttons during Time mode
During a surface interval
• A button: Press this button to scroll to next mode.
• B button: Time display and backlight comes on.
• C button: Activates backlight.
• B+C button: Activates the alarm sound or vibration test
• E button: Touch this button and the metal housing to switch to dive
mode.

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6. Dive Set Mode
To enter Dive Set mode from Time mode, press the A button 2 times
until "DIVESET" is shown at the top of the display.
Note: If the surface interval is less than 10 minutes the computer will
not enter this mode. The computer will switch to dive plan mode.
Use the dive set mode to set the (FO2) MIX1/MIX2 %, user safety factor
(SF-1/2), depth/dive time alarms and on/off, warning alarm (VIBE/SOUND),
DIVE/Gauge mode, and seawater or freshwater (Sea/Fresh) settings. (Fig. 4)
• FO2 (fraction of oxygen): This displays the oxygen concentration
that is currently selected. If the FO2 is set at 21%, "Air" is
displayed, if 22-99% "Nitrox" is displayed.
• PO2 Maximum depth: This displays the PO2 maximum depth (when
PO2=1.4) appropriate for the displayed FO2
• SF (Safety Factor): This displays the SF value set by the diver. The
larger the value, the greater the safety level (SF-0, 1 or 2).
• Alarm operations: The graph will display VIBE, or SOUND.
• Nitrox Icon: This Icon is ON when NITROX has been selected.
• Sea/Fresh Icon: This shows whether the computer has been set to
fresh or salt water for depth calculations.
• Mode: Displays “DIVESET” when in dive set mode.
Nitrox Icon
PO Maximum Depth
Dive Set Mode
User Safety Factor
Max PO
Figure 4
Altitude Icon
FO
2
2
2
Dive Set Mode

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Operation of buttons during Dive Set mode.
• Β: Press the B button to enter/select the function you would like to modify.
• C: Use this button to change the value of the selection. If held
down during the FO2 selection the value will scroll rapidly in one
percent increments. The selected alarm will sound/vibrate for 1 second
when changing the warning setting. The alarm test will not be
performed if the battery is low.
The computer will enter time mode once the E button is released.
If no buttons are pushed for 2 to 3 minutes, the computer will return to
TIME mode.
E: Touch this button and the metal housing to switch to dive mode. •
Dive Set Flowchart

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7. Dive Plan Mode
To enter Dive plan mode from Time mode, press the A button three times
until the "DIVEPLAN" screen is shown.
Note: This mode cannot be entered if the computer is in an out of
measurement range lock or a decompression stop violation lock. In
both instances the computer will skip to the dive log mode.
Please note: altitude measurements are not performed in dive plan mode.
By setting the depth and surface time, the no decompression limit
(NDL) for that depth can be calculated. (Fig. 5,6)
The following information is displayed during this mode:
Surface Time: This displays the time currently elapsed since
surfacing and the total surface time needed to return to the selected
depth.
Depth: This displays the desired depth.
NDL: The no decompression limit for the selected depth, based on
surface time, is displayed. The maximum NDL that can be displayed
is 200 minutes. If the selected depth will result in a PO2 greater than
1.4, the display will show bar.
N2: This will display the PGT (pressure gas in tissue) of nitrogen
absorbed in the diver’s body at the set surface time (Fig. 6).
O2: This will indicate the level of oxygen in the body during the set
surface time.
Nitrox icon: This icon will be on when the FO2 is set at 22 percent or
higher.
Please note: Figure 5 and 6 displays will scroll every 2 seconds to give
the user the ability to view PGT tissue compartment loading data.

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PGT Display Mode
NDL (no decompression limit time)
Depth Setting
(m)
Operation of buttons during dive plan mode
• A: Use this button to move to dive plan mode. If the button is held
down for 2 to 3 seconds the computer will return to time mode.
• B: Press this button to increase and select a desired depth
setting. If the button is held in, the value will scroll rapidly.
• C: Press this button to decrease and select a desired depth setting.
If this button is held in, the value will scroll rapidly.
• Ε: When water is detected the computer moves to dive mode.
• Auto return: The display automatically returns to time mode when
no buttons are used for 2-3 minutes.
NDL (no decompression limit time)
Figure 5
Figure 6
Depth Display Mode

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8. Log Profile Mode
To enter Log Profile mode from Time mode, press the A button five
times until "LOG PROFILE” is shown.
Description of the Log Profile functions
The log profile mode records various data during a dive when the dive
depth is at least 5 feet (1.5m) and the dive time is at least 3 minutes.
Data is recorded during each successive dive, and the log data
storage capacity is about 25 hours of dive time, or up to 25 log data
entries (30 sec sampling rate).
If the logged dive time exceeds 25 hours or the number of log
data entries exceeds 25, the oldest data is automatically deleted.
The logged data is described below. (Fig. 7,8,9)
• Log number: This indicates the number of the log entry being
recorded among the recorded logs.
• Dive date/Dive start time/ Dive end time: This is diving
information. Dive date is the date of the dive. Dive start time is the
time at the start of the dive. Dive end time is the time at the end of
the dive. Both Dive start time and Dive end time are displayed in 24
hour format.
• PGT graph: This displays the level of Nitrogen in each of the 12
tissue compartments at the end of the dive.
• OLI (Oxygen Limited Indicator) graph: This represents the level
of the Oxygen Limit with eight level indicators at the end of the dive.
• Altitude rank: This is the altitude setting used during the dive.
• Nitrox icon: This Icon is ON when NITROX has been used for the
dive
• Fraction of oxygen (FO2): It displays the FO2 which was used
while diving.
• Dive time: This is the dive time.
• Water temperature: Water temperature at maximum depth. The
measurement range is: 23-104°F (-5.0 to 40.0℃). It displays ‘Lo’
when water temperature is under 23°F (-5℃). It displays ‘Hi’ when
water temperature is over 104°F (40.0℃).
• Safety Factor (SF): When the level is "0" the usual algorithm is
used for calculations. When the level is "1" or "2" the next higher
altitude rank is used for the dive calculations. The default setting is
"0".

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• Average depth: This is the average water depth during the dive. If
the depth is over 328 ft (99.9m), the display is ‘---’.
• Maximum depth: This is the maximum depth recorded during a
dive. If the depth is over 328 ft (99m) the display is ‘---’.
• Ascent rate indicator: This is the maximum ascent rate recorded
during a dive.
• Sea/Fresh icon: This indicates the water setting (sea water/fresh
water).
Display 1
Dive number
Log number
Dive date
Display 2
Ascent rate
indicator
No data Display
Safety Factor Water Temp.
Maximum depth
Fraction of oxygen
Dive end
Dive start
Average depth Dive time
Figure 7
Figure 8
Figure 9
PGT Tissue Graph