Cochran COMMANDER EMC-20H User manual

www.divecochran.com
Cochran
EMC-20H
Air Only
Owner's Manual
English - Imperial
Ver: CmdrEMC-20H Air-1.00
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1
PRODUCT INTRODUCTION: The EMC-20H is quite simple to use and
operate, but underneath that simplicity lies a significant level of
sophistication. To get the safest and most effective use of this
instrument, it is important that the user fully understand the product.
Please read and understand this entire manual and know the principles
and practices of safe diving before using this device.
This Manual is divided into the following Sections:
Section Page
•Operation as an Air-only Dive Computer 1
•Alarm Clock Operation 3
•Touch Programming 4
•Warnings 6
•Configurable Items 7
•Specifications and Maintenance 8
•Liability, and Warranty 9
•Itemized Index and Subjects 11
SIDE CONTACTS:
CONTACT #2
CONTACT #1
CONTACT #3
The Contacts are used to let the user command the unit to do a number
of functions, communicate with a PC for extracting information or
configuring the unit, and determining water conductivity. When Contacts
1 & 2 are shorted, the EMC-20H can detect the difference between wet
fingers, metal objects, fresh water, salt water, and a PC interface probe.
TURNING ON THE EMC-20H: Although the EMC-20H automatically
turns on when it is submerged in water, it is STRONGLY recommended
that wetting two fingers and simultaneously touching Contacts 1 and 2 for
two seconds manually power the unit up. This allows the diver to ensure
that the unit is operating correctly and has adequate battery capacity prior
to entry. Once activated, the unit will remain on for 60 minutes. If a dive
is not initiated within this 60 minutes, the EMC-20H automatically shuts
off. Notice that when Contacts 1 & 2 are first bridged, a short beep is
issued which indicates that the unit is recognizing the touch. Every time
Contacts 1 & 2 are bridged with wet fingers, the unit will stay on for one
full hour.
The EMC-20H will not turn on if the altitude is higher than 16,000 feet, the
batteries are less than 1.6 volts, or a fault is detected during the self-test.
As the EMC-20H first recognizes a turn-on command, it begins a
“Diagnostic” function where many aspects of the system will be exercised
and tested. This procedure takes about three seconds and an audible
beep is issued each second as certain tests are successfully completed.
During this time, all of the segments in the display are turned on so that
the user can confirm their operability. Should a test indicate a
malfunction or marginal test, the unit will turn back off again. The user
should ensure that all of the display segments are on and operating
correctly.
TURNING OFF THE EMC-20H: After the Post Dive Interval following a
dive, the EMC-20H will remain on for one hour before automatically
entering its "Sleep Mode". During the Sleep Mode, all calculations
continue, but the display is off. This is a power saving feature of the
EMC-20H. The unit will continue calculating Surface Interval,
compartment off gassing as required, and any changes in altitude as it
affects Nitrogen Loading. The current Surface Interval and PreDive
Predictions can be viewed by reactivating the unit.
MAIN EMC-20H OPERATING MODES:
•Surface Interval (No Nitrogen Residual)
•Surface Interval (With Nitrogen Residual)
•Dive Mode (Normal No Deco)
•Decompression Mode
•Post Dive Interval
•Touch Programming
SURFACE INTERVAL:
After completion of the Self-Diagnostic mode or after the Post Dive
Interval following a dive, the EMC-20H enters the Surface Interval. The
Screen displays, if applicable; current Surface Time, the previous dive’s
Maximum Depth, the previous dive’s Bottom Time, Dive of Day number,
current Time to Fly, Altitude and Temperature. Figure 2 shows the
display with no residual Nitrogen (a clean Dive).
Figure 5 shows the display with residual Nitrogen (a repetitive dive).
“Surface Time” starts at zero after a dive and begins counting minutes. If
the computer shuts off and is turned on with Nitrogen residual left, the
Surface Time continues to count. If the computer shuts off and is
turned on with no Nitrogen residual left, the Surface Time will be zero.
“Dive of Day” starts at zero and increments after each dive regardless of
the calendar day. When there is no remaining Nitrogen residual, the Dive
of Day is set to zero and the computer is referred to as a “clean” system.
“Time to Fly” is displayed as the number of hours remaining until the
Nitrogen residual reaches zero plus a twelve-hour safety factor. Flying is
not recommended until Time to Fly reaches zero.
“Barometric Altitude” is indicated in six ranges via the Ascent Rate Bar
Graph as follows (Altitude compensation is seamless up to 16,000 feet
above sea level):
0 Bars sea level to 2,500 feet
1 Bar 2,500 to 5,000 feet
2 Bars 5,000 to 7,500 feet
3 Bars 7,500 to 10,000 feet
4 Bars 10,000 to 12,500 feet
5 Bars 12,500 to 16,000 feet
The six ranges are for display purposes only: The EMC-20H actually
senses and computes extremely small altitude changes and hence, is
called “Seamless”. The term “Barometric Altitude” is used instead of just
“Altitude” because the EMC-20H measures Barometric Pressure to
determine Altitude. Barometric Altitude can vary from actual Altitude by
over +/- 1000 feet! What is important to the body when diving is
Barometric Altitude.

2
DIVE MODE:
Whether in the Surface Interval, PreDive Prediction Mode, Programming
Mode or the Logbook Mode, the EMC-20H will automatically enter the
Dive Mode whenever the unit determines that it is in water deeper than
five feet.
On the Display Screen the Surface time will be replaced with the current
Depth and be displayed in one-foot increments. The maximum specified
depth is 427 feet, but the unit will continue to measure and display depths
deeper that that. A Depth Sensor warning will be issued (See later
discussion on Sensor Warnings) when the unit can no longer accurately
measure depth.
A Depth Alarm, which can be set to warn the diver should a certain depth
be exceeded, is set at 130 feet from the factory. The Depth Alarm issues
an audible alarm and the “WARNING” legend and Depth Digits will flash
on and off for five seconds. The depth alarm is disabled if in the
Decompression Mode since flashing depth digits have another meaning
in this Mode.
The maximum depth achieved on the current dive is shown as “MAX
DEPTH”. This is updated once per second.
“REMAIN TIME” (NDC) is the remaining time (in hours and minutes) that
the diver can stay at the current depth without requiring decompression.
A “Two Minute Warning” will be issued when this time reaches two
minutes or less. An audible alarm will be issued and the “WARNING”
legend and “REMAIN TIME” digits will flash. By immediately ascending
to a shallower depth, the diver may avoid a required decompression stop.
Temperature is measured for two purposes. One is to compensate the
Depth Transducer for Temperature variations. The other is to
compensate the Nitrogen algorithm for changes in Temperature that may
affect the body. Both of these purposes require that the Temperature be
very slow reacting, just like the Depth Transducer and the body. This
slow-reacting Temperature is what is displayed. For Temperature effects
on the body, the amount of compensation can be set from NORMAL to
REDUCED with the Analyst® PC software Interface (see Analyst®
Section), if the diver is using a good dry-suit in cold water. Temperature
compensation starts at 75 degrees F and gets progressively more
conservative as the temperature decreases. There is no compensation
above 75 degrees F.
Bottom Time will begin once the EMC-20H senses that the diver has
descended below five feet (see Training Mode) and continues until the
diver has ascended above three feet. The maximum Bottom Time
displayed is 9 hours 59 minutes.
ASCENT RATE BAR GRAPH:
The Ascent Rate bar graph and alarms are active in both the Dive Mode
and Decompression Mode. The five-segment bar graph is used to
display the diver's rate of ascent.
Via the Analyst®PC Interface, the Ascent Rate Alarms and Bar Graph
can be set to the users preferences.
The first option is a VARIABLE-BY-DEPTH Ascent Rate. When on, the
Ascent Rate Alarm is determined by depth. As the diver ascends to
shallow depths, the Maximum Ascent Rate is lowered. The Maximum
Ascent Rates and their associated depth are:
60 feet or deeper 60 feet per minute
60 to 30 feet feet per minute equal to the depth
Less than 30 feet 30 feet per minute
If VARIABLE-BY-DEPTH is off, the Maximum Ascent Rate Alarm and Bar
Graph is specified by the user and can be from 20 to 60 fpm, in one foot
increments.
Another selection is the bar graph itself. The two selections are either
FIXED or PROPORTIONAL.
With FIXED, each of the five bars indicates an additional 10 feet per
minute of Ascent Rate regardless of the Maximum Ascent Rate selected.
With PROPORTIONAL, each of the five bars indicates 20% (one-fifth) of
the selected Maximum Ascent Rate.
For FIXED, the maximum ascent rate is 60 feet per minute. With this
setting, no bars will illuminate if a diver is ascending at a rate less than 10
feet per minute.
If the diver has an Ascent Rate that exceeds the selected maximum, the
entire Ascent Rate Bar Graph will flash, and the audible alarm will sound
once per second, and the WARNING legend will illuminate.
The sensitivity or responsiveness of the Ascent Rate may be selected via
the Analyst®, eight different levels of sensitivity are available.
NOTE: Customizing the Ascent Rate and Ascent Rate Bar Graph are
among many of the additional programmable features available when
using the Analyst®PC Interface. Available features are described in the
section “USER CONFIGURABLE OPTIONS”.
As shipped from the factory, the Ascent Rate is set for VARIABLE-BY-
DEPTH AND PROPORTIONAL.
DECOMPRESSION MODE:
Should a no-decompression limit be overstayed, the EMC-20H will enter
the Decompression Mode. In this mode, the Ceiling digits will display the
depth at which the diver must stop and not ascend above during final
ascent. The “TEMP” legend and two digits will be replaced with the
“CEIL” legend and two digits. The Ceiling will start at 10 feet and
increase in ten-foot increments as the diver remains at a relatively deep
depth.
The Remaining No-decompression Time and “NDC” legend will be
replaced with Decompression Time and “DEC” legend (Figure 16d). Both
STOP time and TOTAL time are displayed in the upper left hand three
digits of the screen in hours and minutes. STOP and TOTAL time will
alternate at the rate of once every two seconds. In this way, the diver
can view the time to spend at a particular STOP depth, and the TOTAL
time it will take to complete all STOPS. Clearly, the larger of the two
alternating numbers is the Total Decompression Time of all stops, and
the smaller of the two numbers is the time required at the current stop. At
the ten-foot stop, the TOTAL and STOP times may be the same and
therefore appear to not alternate.
When at a specific stop, the required decompression time at that stop is
as shown, and will appear to count down as it is recomputed every
second, based on the divers exact current depth. The Decompression
times (both Stop and Total) are accurate only if the divers depth is exactly
the same as the required Ceiling. However, it is not necessary to be
precisely at that specified Ceiling. Appropriate In-gassing or Out-gassing
will be computed regardless of the divers current depth.
A small margin shallower than the Ceiling also exists. Should a Ceiling
be ‘violated’ (diver is shallower than Ceiling), the “WARNING” legend will
illuminate and flash along with the Depth and Ceiling digits. An Audible
alarm will sound once every two seconds. This warning will continue until
the Depth has been corrected. Out-gassing will continue even though the

3
diver is shallower than the Ceiling. There is no ‘Gauge’ mode or
‘Lockout’ on the EMC-20H.
If the diver surfaces before satisfying his decompression obligation, the
EMC-20H will continue to give out-gassing credit as if it were in a dive,
but at a depth of zero feet and will satisfy the decompression time
requirements of the required stops using an FO2of 21%. The unit will
continue to log data and perform as if actually in a dive. When the
decompression obligation is finally satisfied, the ten-minute “Post Dive
Interval” will begin.
NOTE: COCHRAN does not intend for this instrument to be used for
deliberate Decompression diving.
POST DIVE INTERVAL: During the first ten minutes (or up to thirty
minutes if the unit is in the Training Mode) after a dive, the EMC-20H is in
the Post Dive Interval. The flashing "SURF" legend and a Surface Time
of less than ten minutes (or up to thirty if the unit is in the Training Mode)
indicate this. Should another dive be commenced before the completion
of the Post Dive Interval, that dive will be considered an extension of the
previous dive. In this case, Bottom Time will NOT include the time spent
on the surface in this Post Dive Interval. However, when reviewing the
profile with the Analyst®, the time spent on the surface in this period will
be shown.
CONFINED WATER PROTOCOL (Training Mode): The EMC-20H is
one of the first dive computers to offer an operating mode designed to
record and store data from training dives. That is, dives performed in
shallow water environments (swimming pools, shallow lakes, lagoons,
etc.) or calm open water environments that have less than 1-foot seas. In
the Training Mode, the EMC-20H enters the Dive Mode at a depth of 2
feet instead of 5 feet and will exit the Dive Mode at 1 foot instead of 3
feet. Also the Post Dive Surface Interval may be extended, via the
Analyst®, from 10 minutes up to a maximum of 30 minutes in 1-minute
increments after which the dive data is stored in the computer's memory.
These changes permit the Instructor to record the complete training
session, including in-water surface periods, as a single dive. The
Training Mode can only be enabled/disabled via the Professional
Edition of the Analyst®PC Interface.
TACLITE™: The EMC-20H is equipped with the TACLITE™ tactical low-
light fiber-optic backlighted display. The standard TACLITE™ color is
night vision safe red, but it is also available in yellow for those individuals
who have vision difficulties with the color red. The TACLITE™ can be
activated on demand. To turn the TACLITE™ on, tap the face of the
EMC-20H and the TACLITE™ will turn on for the preprogrammed number
of seconds (1 to 98), then turn off. By tapping the face again the
TACLITE™ will turn on again. In this fashion the TACLITE™ can be kept
on for as long as wanted. If 0 is entered, the TACLITE™ will never turn
on. If 99 is entered; the TACLITE™ will stay on continuously and only
turn off when the EMC-20H does. The number of seconds that the
TACLITE™ stays on can be set via the Programming Mode or via the
Analyst®PC Interface, factory setting is 10 seconds. The TACLITE™ will
turn off when the EMC-20H turns off. If the batteries get too low, the
TACLITE™ will turn off and cannot be turned back on until fresh batteries
are installed.
CLOCK MODE: The Clock operating mode of the EMC-20H is NOT
enabled when shipped from the factory. It can be enabled via the
Analyst® P.C. Interface or at an Authorized Cochran Dealer.
TOUCH PROGRAMMING MODE: Can only be accessed when the unit is
in the Surface Interval and allows the user to view or program into the
dive computer:
•Setting Clock and Alarm Time
•The PreDive Prediction Mode
•Displaying Mode, mode value, & battery voltage
•A Maximum Depth Alarm
•An Added degree of Conservatism from 0 to 50%
•Programming the On Time for the TACLITE™
•Access the Logbook Mode
TOUCH PROGRAMMING - CLOCK: When the EMC-20H is placed into
the Clock mode it will display the time of day in a 24 hour day format.
The clock will continue to run when the EMC-20H is in the Dive Computer
Mode. The EMC-20H can be placed into the Clock Mode from the Dive
Computer Mode when the unit is in the Normal Surface Interval, while the
unit is in Clock Mode the Dive Computer will be in the “Sleep” mode.
The Clock Mode can be selected with or without an Alarm. If the Alarm
option is selected the unit will display the alarm set time as well as the
current time.
When the alarm time is displayed the alarm is activated and at the
programmed time the alarm will sound once every 24 hours. When the
alarm is activated the unit will issue a medley of all the audible warning
tones that the EMC-20H utilizes and the TACLITE™ will flash for one
minute, this audible alarm can not be turned off, it will sound for the full
one minute period.
The Clock Mode is selected via Touch Contact Programming.
NOTE: This Time of Day clock is the same clock that is used to time
stamp dives. Modifying the Time of Day clock will effect the Local
Time as viewed via the Analyst®. The Date portion of the Local Time
clock must be changed via the Analyst®.
CLOCK PROGRAMMING PROCEDURE:
Contacts 1, 2, & 3 are for programming sequences.
To begin the programming sequence:
1. Turn the unit on;
2. Using a coin or other conductive metal object, briefly bridge
Contacts 1 and 2 until a short beep is heard and the Clock Menu is
seen on the display.
3. To enter the Clock submenu, bridge Contacts 1 & 2 with wetted
fingers. This will cause the unit to display the Clock Alarm selection
– On or OFF. To Toggle the selection, bridge contacts 1&2 with
wetted fingers.
4. Using a coin or other conductive metal object, bridge Contacts 1 & 2
to access the Clock Time or Alarm setting screen.
5. Shorting Contacts 1 & 2 with a coin will cause the first digit of the
minutes to flash.
6. Shorting Contacts 2 & 3 with a coin will increment the numeric value;
continue until the required value is displayed. A confirmation beep
will sound with each increment.
7. Next using wetted finger, bridge Contacts 1 & 2 to select the next
digit, once selected the digit will flash to identify that it is being
programmed. Bridge Contacts 2 & 3 till the desired value is
displayed.
8. To select Hours short Contacts 1 & 2 with a coin, increment as in
step 6 and 7.
9. Repeat step 5 through 7 until all digits have been programmed.
10. To save the changes that have been made bridge Contact 1 & 2
with a coin or other conductive metal object. Once the next
programming option is displayed the changes have been saved.
To exit the Clock Mode Bridge contacts 1 & 2 with wetted fingers and the
computer will return to the Dive Computer Mode’s Surface Display.
NOTE: Ensure that the EMC-20H is in the Dive Computer Mode
before commencing a dive.

4
Figures 40, 41a, 41b, 42 and 43 show how the Clock display screens
appear.
NOTE: Once the EMC-20H is placed in Clock Mode the unit will
remain in that mode until exited by the diver.
TOUCH PROGRAMMING MODE:
NOTE: To enable the Programming Mode, the EMC-20H must be on
the Surface and not in the Post Dive Interval.
NOTE: All audible and visual alarms are suspended while the EMC-
20H is in the Programming Mode. Upon exiting the
Programming Mode all alarms are reactivated.
NOTE: Once a value has been changed and the next menu option
selected, the new value is stored.
NOTE: It is strongly recommended that the Programming Mode is
activated again and a complete review of what was stored is
accomplished.
NOTE: If the EMC-20H is left in the Programming mode for five
minutes without the contacts being touched, the unit will
automatically exit the Programming Mode and return to the
Surface Interval. Once this occurs the EMC-20H will retain
the modified programmed settings that have been stored.
Options that have not been modified will retain their previous
settings.
TOUCH PROGRAMMING MODE - PROCEDURE:
Contacts 1, 2, & 3 are for programming sequences.
To begin the programming sequence:
1. Turn the unit on;
2. Using a coin or other conductive metal object, briefly bridge Contacts
1 and 2 until a short beep is heard and the Programming Menu is
seen on the display. The Programming Menu options depend on
whether the unit is activated for Clock. The Menu options are
displayed in sequence, incrementing to the next selection each time
that Contacts 1 & 2 are bridged with a coin. The program option is
displayed on the upper row of the display. The current setting for this
option is displayed in the lower right of the display.
3. To reprogram the displayed menu values, bridge Contacts 1 & 2 with
wetted fingers. This will cause the current setting to flash or in the
case of multi-digit numbers, the least significant digit will flash. The
clock will toggle between on and off.
4. Using a coin or other conductive metal object, bridge Contacts 2 & 3
to increment the numeric value. A confirmation beep will sound with
each increment.
5. Next using wetted finger, bridge Contacts 1 & 2 to select the next
digit, once selected the digit will flash to identify that it is being
programmed. Bridge Contacts 2 & 3 till the desired value is
displayed.
6. Repeat step 5 until all digits have been programmed.
7. To save the changes that have been made bridge Contact 1 & 2 with
a coin or other conductive metal object. Once the next programming
option is displayed the changes have been saved.
All programming sequences use the same routine of using Contacts 1
and 2 to SELECT the next programming sequence and Contacts 2 and 3
to INCREMENT the specified value.
PROGRAMMING MODE MENU:
The following table lists the various programming choices with their
display identification and figure number.
Identification Description Figure Page
CLC Clock – if enabled 40 4
PdP PreDive Prediction 22 4
InF Misc. Information 23 4
dEP AL Depth Alarm, Max value
is 410 feet 25 4
Con Added Conservatism, Max
value is 50%. 26 4
Tac dL TACLITE™ On Time. Allowed
value 0 to 99 33 4
LOG Logbook 34a 5

5
TOUCH PROGRAMMING - PREDIVE PREDICTION:
PreDive Prediction is accessed via the Touch Contact Programming
Menu. This enables the diver to view the PreDive Prediction information
at the touch of the Contacts. The EMC-20H’s PreDive Prediction starts at
30 feet and increases in 10 feet increments. PreDive Predictions will
terminate when the No-Decompression (NDC) time prediction reaches
two minutes or a maximum depth of 410 feet is reached. Additional
Conservatism, Residual Nitrogen and Barometric Altitude can effect
PreDive Predictions. Once the maximum PreDive Prediction depth has
been reached the unit will return to the Surface Interval.
Refer to the Analyst®for information about how to modify parameters.
During the PreDive Prediction Mode, the unit will compute and display the
maximum safe time and the calculated PO2value at that depth.
TOUCH PROGRAMMING INFORMATION DISPLAY: The Information
display is accessed via the Programming Mode. The information
presented will appear as in Figure 24. The information in the upper right
of the screen indicates the unit is in the Air Only FO2 Mode.
Identifier Description
F0 Air only
The Battery voltage is displayed in the lower center of the screen as a
two-digit number with a decimal point proceeded by a lower case ‘b’.
Figure 24 shows what the display screen looks like for a EMC-20H
configured for Air Only.
TOUCH PROGRAMMING - DEPTH ALARM: The Depth Alarm allows
the diver to select a maximum depth below which the diver does not wish
to descend before an alarm is issued. This depth can be set from 0 to
410 feet in one-foot increments.
TOUCH PROGRAMMING - CONSERVATISM: This programming
function allows the diver to input an added degree of Conservatism into
the EMC-20H’s nitrogen algorithm. Via Touch Programming the
Conservatism can be set from 0 to 50%.
TOUCH PROGRAMMING - TACLITE™:
The Taclite™ dwell (on) time can be set so that when the face on the
EMC-20H is tapped the Taclite™ will stay on from 1 to 98 seconds. If the
dwell time is programmed to ‘0’ the Taclite™ will never come on, if
programmed to 99 the Taclite™ will be on whenever the EMC-20H is
awake.
TOUCH PROGRAMMING - LOGBOOK:
The Logbook of the EMC-20H has two screens, a Primary Screen and an
Alternate Screen. To switch to the Alternate Screen just tap firmly on the
face of the unit. The Logbook is accessed via the Touch Contact
Programming (see page 13). This enables the diver to view dive
statistics; the EMC-20H has the ability to provide diving data for the most
recent 512 dives. The most recent dive will be displayed first. To view
the next dive, touch the contacts 1 & 2 with wetted finger after pausing for
a few seconds. Do not use a metal object such as a coin or knife-blade
once in the Logbook since it will cause the unit to exit the Logbook and
return to the Surface Interval.
Information contained in the Logbook will include:
Overall Dive Number Minimum NDC Time
Fastest Rate of Ascent Minimum Water Temperature
Bottom Time Surface Interval Before Dive
Maximum Depth Ending Battery Voltage
Beginning Dive Time & Date
Maximum DEC Time (Deco Dive)
Maximum Ceiling (Deco Dive)
It is not necessary to exit the Logbook Mode prior to initiating a dive.
Once the diver has descended below five feet, the EMC-20H will
immediately enter the Dive Mode.
NOTE: The overall Dive Number that is displayed on the Logbook Menu
screen (Figure 34) permits the diver to identify the total number of dives
made with that EMC-20H. If the logbook example shown is the most
recent dive made, it can be readily identified that 235 dives have been
made with this specific unit.

6
Figure 34b shows that dive 235 started at 14:26 hours or 2:46 pm on the
18th of December 2001.
Figures 35 & 37b display the Logbook of a Normal Dive.
Figures 36 & 38b display a Deco Dive.
WARNING INDICATIONS: Failure to observe audible and/or visual
warnings and take corrective action may result in injury or death. In
general, if the WARNING legend is flashing, some other digits should be
flashing to indicate the anomaly.
•If the diver is ascending faster than the selected maximum ascent
rate, then the top bar of the ascent bar graph will flash and the
“WARNING” legend will illuminate. The unique high to low audible
sweep alarm will continue to sound once per second until the
situation is corrected.
•If the diver descends below the user set Depth Alarm, the Depth
digits will flash. A single beep audible alarm will sound once per
second for five seconds and will repeat every two minutes. The
Depth alarm is not active in the Decompression Mode to avoid
confusion with the “Shallower Than Ceiling” alarm.
•If the battery voltage declines to 2.5 volts, the “BATT” legend will
illuminate, at 2.2 volts it will flash once per second.
•If the diver has less than two minutes of No-Decompression Time
(NDC) remaining, the “WARNING” legend will illuminate and flash
along with the Remaining NDC time digits. A single beep audible
alarm will sound once per second for five seconds and repeat every
two minutes.
•If the diver enters the Decompression Mode, a single beep audible
alarm will sound once per second for five seconds.
•During a Decompression dive, if the Depth is less than the CEILING,
the “WARNING” legend will illuminate and flash along with the Depth
and Ceiling digits. A unique low to high audible sweep alarm will
continue to sound once every two seconds until the situation is
corrected.
•If the dive computer determines that either the Depth or
Temperature sensor is malfunctioning. The “WARNING” legend will
illuminate, the computer will issue a 5-beep two-tone audible alarm
once every two-minute to alert the diver to this condition. On the
Appropriate Screen the Maximum Depth will be replaced with “S-d“
or "S--" to indicate the low-pressure transducer or “S-t” for the
temperature transducer.
If an audible alarm is being issued, the computer will not switch to the
Alternate display nor will the TACLITE™ activate.
SENSOR WARNING: The EMC-20H has the capability of monitoring the
integrity of its' sensors, both the low-pressure (depth/altitude) and the
temperature. When the computer detects an error in one of the
transducers, the diver is alerted to this condition by the illumination of the
“WARNING” legend, and the computer will also issue a 5-beep two tone
audible alarm once every two minute to alert the diver to this condition.
The Maximum Depth will be replaced with “"S--" to indicate the low-
pressure transducer or “S-t” for the temperature transducer (see figure
18). The “WARNING” legend, along with either the Temperature digits or
the Depth digits and the error code will flash once per second. In the
highly unlikely situation were both sensors are detected as having errors,
the display will alternate between "S--" and “S-t”. This warning will be
issued whether the computer is in the Surface Interval, Dive Mode,
Decompression Mode or Post Dive Interval. In the unlikely case that your
computer issues one of these warnings the unit should be returned to the
factory for evaluation and/or repair. Figure 18 shows a Sensor Warning,
in this case a Depth Sensor, as it would be displayed in the Dive Mode. If
the Sensor Warning were for the temperature sensor it would display “S-
t“.
DATA STORAGE TYPES & CAPACITY: The EMC-20H has the
following internal distinct data storage activities that can be recalled,
viewed, and stored with the Analyst®PC computer interface:
•Current Variable Information: Local Time, Altitude, Battery
voltage, Current unit Temperature, and 20-tissue loading.
•Current Configuration Data: As can be seen in “USER
CONFIGURABLE ITEMS”, below.
•Historical Totals Summaries: Dive Time, Number of Dives,
Number of Marginal Dives, Number of Violated Dives, Number of
Warnings, Decompression Dives, Decompression Time, Maximum
Depth and Ceiling, Maximum Depth and Ceiling Dive Number.
•Each Dive Beginning Statistics: 20-tissue loading, Local Time
Clock, Dive of Day, Dive Number, Surface Time, Altitude, Time to
Fly, and Battery Voltage. Capacity is the most recent 1024 dives.
•Each Dive Ending Statistics: 20-tissue loading, Bottom Time, Max
Depth, Average Depth, Min NDC Time, Max Deco Time, Max Deco
Ceiling, Missed Ceiling, Missed Deco Time, Max Ascent Rate, Max

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A/R Time, Max A/R Depth, Min Temperature, Average Temperature,
Maximum Temperature, Min Battery Voltage, Time to Fly, and
number of Warnings. Capacity is the most recent 1024 dives.
•Each Dive Configuration Data: Full and complete configuration of
the system, including User Conservatism. Capacity is the most
recent 1024 dives.
•Profile Graphical Information: Depth Graph, Ascent Rate Graph,
and Temperature Graph. Capacity is 135 hours (or 1440 hours with
expanded memory upgrade) at one second sampling.
•Inter-Dive Events: Number of Initializations, Unit Activation,
Altitude Changes of 500 Feet, Temperature Changes of 10 degrees,
Low Batteries, Sensor Malfunction, Analyst®interface with Dive
Computer.
INTER-DIVE EVENTS: The EMC-20H stores important information
between dives, even when the unit is not turned on. The information is
stored as acquired and is called an “Inter-Dive Event”. These events can
be viewed via the Analyst®P.C. Interface version 4.00 or higher. Some
Inter-Dive events are:
•Initialization of the unit.
•The unit is turned on
•Low batteries
•Altitude Changes of over 500 feet
•Temperature Changes of 10 degrees F
•Sensor Malfunction
•Analyst®P.C. Communication
USER CONFIGURABLE ITEMS: By using the optional Analyst®
Personal Computer Interface, the user has the ability to change the
following items:
Caution: Items that can be changed via Touch Contact Programming
may be different from the factory settings.
Dive Time/date Stamp: This is the internal clock that is used by the
system to time-stamp each individual dive as it occurs. Due to changes
in battery voltage and temperature, the internal Time-of-day clock may
slowly drift from the ideal. It is recommended that this clock be
periodically set to local time via the Analyst®.
Metric or Imperial: The diver may select whether the data is computed
and displayed in Metric or Imperial units. The EMC-20H may be ordered
either way as shipped from the factory.
Selectable Ascent Rate Bar Graph (Fixed or Proportional): This
option determines whether the Ascent Rate bar graph indicates the
speed of ascent or the percentage of the selected maximum ascent rate.
The EMC-20H is shipped from the factory as ‘Proportional’ (percentage).
Selectable Variable-By-Depth Ascent Rate Alarm (On or Off): This
option gives the diver the ability to utilize a fixed ascent rate warning or a
warning based on depth. Should the diver prefer the fixed ascent rate
warning the diver can select the maximum ascent rate limit from 20 to 60
feet per minute (See next topic). As shipped from the factory, this is set
to ON. If the VARIABLE rate is selected then the warning will illuminate
based on the following table:
DEPTH AVERAGE ASCENT RATE
60 feet and deeper 60 feet per minute
60 to 30 feet same as depth
Shallower than 30 feet 30 feet per minute
Selectable Fixed Ascent Rate Alarm Limit: If Variable-By-Depth Ascent
Rate Alarm was set to OFF from the above topic, the user may enter the
desired Ascent Rate for the alarm to sound.
Ascent Rate Responsiveness (0 to 7): This option determines the
responsiveness or sensitivity of the Ascent Rate Bar Graph. Zero is
highly responsive and seven is very slow. This feature is set to three as
shipped from the factory.
Remaining Time Responsiveness (0 to 7): This determines the
responsiveness of the Remaining Time information that is displayed.
Zero is highly responsive and seven is very slow. This feature is set to
three as shipped from the factory
Max Depth Alarm: This option allows the diver to select a maximum
depth below which the diver does not wish to descend before an alarm is
sounded. This function is disabled when in the Decompression Mode.
This option may also be set via the Touch Contact Programming. As
shipped from the factory, the Depth Alarm is set for 130 feet.
Select Decompression Time Display (Total, Stop, Both): There are
three options for the manner in which the decompression time is
displayed. If you select TOTAL, the decompression time displayed will
indicate the total time you will spend in decompression.
Watch the Ceiling depth change in order to identify when to ascend to the
next stop depth. If you select STOP, the decompression time displayed
will indicate the time you must remain at the current Ceiling. When this
time is 0:00, the Ceiling depth will decrease and the new stop time will be
displayed. If you select BOTH, the TOTAL time and STOP time will
alternate at the rate of once every 2 seconds. From the factory, the unit
is set to ‘Both’.
Repetitive Dive Dependent Nitrogen (Off or On): This option allows the
dive computer to consider recent dive history’s effects on the nitrogen
loading, particularly if the diver engages in inverted profile diving. If “On”
the recent dive history is used to compensate the nitrogen loading for the
current dive. The EMC-20H is shipped from the factory with this feature
set to ‘Off’.
Temperature Dependent NDC Computations (Normal or Reduced):
This feature compensates the decompression algorithm proportional to
the ambient water temperature. See User & Environmental Adaptation,
Water Temperature on page 34 for a detailed description of this function.
The EMC-20H is shipped from the factory with this feature set to ‘Normal’.
Select Altitude <2000 feet as One Zone (Off or On): This option
provides "actual" altitude for any given day at any diving location as
explained in the “ALTITUDE ACCLIMATIZATION” on page 35. With
changes in barometric pressure due to temperature and weather
systems, it is possible, even expected, to have a different apparent
altitude at the same dive site from day to day.
While the seamless means of monitoring provides the most accurate
decompression schedule, all altitudes less than 2,000 feet above sea
level can be treated in the algorithm as sea level if so selected. With this
option ‘OFF’, the unit is calculating altitude in a seamless fashion. With
this option ‘ON’, altitudes less than 2,000 feet above sea level will be
treated as sea level. Regardless of the selection, altitudes greater than
2,000 feet above sea level will be treated in a seamless manner. From
the factory, this is set to ‘Off’, seamless altitude from sea level to 15,000
feet.
Select Alternate Screen Viewing Time (3 to 10): This option allows the
diver to set the amount of time that the Alternate Screen will be viewed
once it has been accessed. From the factory this is set to 4.
Select Display Backlight On Time (0 to 99): This option allows the user
to set the amount of time, in seconds, that the TACLITE™ stays on once
activated. If this option is set to "0" the TACLITE™ will never activate, if
set to "99" the TACLITE™ will stay on all the time and only turn off when
the EMC-20H does. This option may also be set via the Touch Contact
Programming. From the factory this is set to 10.
Select Audible Beeper Alarm (On or Off): This allows the user to
enable or disable the Audible Alarms and beeper. As shipped from the
factory, this is set to ‘On’.
Select Ceiling Display Divided by 10 (On or Off): This option allows
the diver to select when in the Decompression Mode the Ceilings are
displayed as 1 = 10, 2 = 20, 3 = 30 etc. (On) or as 10, 20, 30 etc (Off).
From the factory this option is set to ‘Off’.
Selectable NDC Conservatism (0% to 50%): This feature allows the
diver to input an added degree of conservatism to the decompression
algorithm from 0 to 50 percent in one-percent increments. This may be
desirable if the diver is dehydrated, tired, or has some other factor that
warrants added conservatism. This option may also be set via the Touch
Contact Programming. Conservatism is set to ‘0%’ as shipped from the
factory.
Confined Water Protocol (Training Mode) - (Enabled or Disabled):
This option enables the Training Mode for the EMC-20H. In this mode
the EMC-20H will enter the Dive Mode at 2 feet instead of 5 feet and exit
the Dive Mode at 1 foot instead of 3 feet. The Training Mode also
permits the selection of an increased Post Dive Interval period from 10 to
30 minutes in one-minute increments. These changes permit the
Instructor to record a complete training session, including in-water
surface periods, as a single dive. As shipped from the factory, this is set
to ‘Disabled’. This option can only be ‘Enabled’ via the Professional
Edition of the Analyst®.
Training Mode Post Dive Interval Period (10 to 30): If the Training
Mode is enabled this allows the user to select the duration of the Post
Dive Interval period from a minimum of 10 minutes to a maximum of 30
minutes in one-minute increments. As shipped from the factory, this is set
to 10. This option can only be set via the Professional Edition of the
Analyst®.

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Select Clock Functions (ON or OFF): This option allows the diver to
enable or disable the time of day Clock. If it is set to ‘ON’ the clock time
can also be set via Touch Contact Programming. As shipped from the
factory, this is set to ‘OFF’.
Enter Clock Time: This allows the diver to set the clock’s time to that of
the P.C. time.
Select Alarm Clock Audible Alarm (ON or OFF): This option allows the
diver to enable or disable the time of day Clock’s Alarm feature. If set to
‘ON’ the Alarm Clock time can also be set via Touch Contact
Programming. As shipped from the factory, this is set to ‘OFF’.
Enter Alarm Clock Hour (0 to 23): This allows the diver to program the
time of day Alarm Clock’s hour setting. The Alarm Clock’s time utilizes a
24 hour format, i.e. 00:00 = 12:00 am, 20:00 = 8:00 PM, etc. This is also
settable via Touch Contact Programming.
Enter Alarm Clock Minute (0 to 60): This allows the diver to program
the time of day Alarm Clock’s minute setting. This is also settable via
Touch Contact Programming.
Restore Original Configuration Settings: This allows the diver to
restore the original factory default settings with a single command.
SPECIFICATIONS:
Algorithm 20 Tissue Adaptive Modified Haldanean
Computation Period Once every second
Activation Manual and Water
Maximum Depth Over 427 feet, 1 foot increments
Depth Accuracy +/- 1% of full scale (+/- 3.3 feet)
Maximum Altitude 16,000 feet, seamless
Altitude Accuracy +/- 1000 feet
Temperature Display 0 to 99 degrees F, 1 degree increments
Temperature Accuracy +/- 2% of full scale (after the unit has
stabilized from a change in Temperature)
Surface Time 0 to 9:59 hrs/mins, 1-minute increments
Bottom Time 0 to 9:59 hrs/mins, 1-minute increments
Time To Fly 0 to 48 hours, 1 hour increments
No-Deco Time 0 to 9:59 hrs/mins, 1-minute increments
Decompression Time 0 to 9:59 hrs/mins, 1-minute increments
Decompression Ceiling 0 to 410 feet, 10-foot increments
Dive Summary Storage up to 1024 Dives
Dive Profile Storage up to 1440 Dive hours at one second sampling
depending on configuration
Profile Sampling 1 second increments
Typical Battery Life* Over 1000 dive hours under normal diving
conditions or one years (whichever is first),
TACLITE off.
Over 40 hours, TACLITE on continuously.
Typical Battery Life* Over 5000 dive hours under normal diving
conditions or two years (whichever is first),
TACLITE off.
Over 75 hours, TACLITE on continuously
* With fresh new ENERGIZER®brand alkaline batteries
** With fresh new Lithium battery
Note: Specifications are additionally +/- one least significant digit due to
rounding. Specifications are subject to change without notice.
ENHANCEMENTS: The EMC-20H is capable of having its’ capabilities
enhanced. It can be upgraded to a one blend Nitrox (can be done by an
Authorized Dealer) or two blend Nitrox computer or a One or Two blend
Nitrox/PO2computer or any of the afore listed with Helium. The Dive
Profile Storage memory capacity can be upgraded from a base of 135
hours to 1440 hours. The EMC-20H must be returned to the factory
for all upgrades except to that of a one blend Nitrox.
CLEANING THE EMC-20H: Clean the unit only with fresh water after
each use. Towel dry the unit, never use air pressure to dry the unit. This
could damage the unit and will void the warranty. Do not use chemicals to
clean the case or lens as this may damage the unit, or permanently fog
the lens.
CHANGING BATTERY: The EMC-20H will operate on either one 3V
Lithium Battery (CR12600SE or CR2NP) or two 1.5V N-Cell size Alkaline
batteries. The battery(s) should be changed when the ‘BATT’ legend is
seen or battery voltage reaches 2.5 volts as can be seen on the
Information Display. The unit will operate until the battery voltage drops
below 2.0 volts. Only use fresh batteries for maximum battery life. At this
time, Eveready Energizer Alkaline is recommended for the N-Cells. Care
should be taken not to activate the TACLITE™ during battery
replacement. Be sure to confirm that the batteries are REALLY new and
have not been sitting on a shelf losing life. Cold temperatures tend to
shorten apparent battery life. Change batteries every two years
regardless of battery condition.
Plus end goes in First.
When installing new batteries, ensure that the positive “+” end of the
battery is inserted into the battery compartment first. Inspect the battery
cap O-rings for nicks and scratches. If either O-ring is damaged carefully
remove both O-rings and replace with new silicone O-rings. Lightly
lubricate each end of the batteries with silicone grease or petroleum jelly
to help minimize corrosion and therefore extend battery life.
When reinstalling the battery cap, lightly lubricate the O-rings and slowly
twist the cap into place using a coin (US Quarter supplied). Press the
coin into the battery cap slot firmly to prevent slipping and damaging the
slot. Ensure there is no dirt or debris on the O-rings or the mating
surface and that the O-rings are properly installed.
As the battery cap is screwed in, carefully observe that the double O-
rings install correctly.
It is best to have the new batteries ready to install since the EMC-20H
was designed to allow for battery changes without resetting. This period
of time is typically 30 seconds, but varies with temperature and the
voltage of the batteries being replaced. It can be significantly less if
batteries are not replaced promptly when the ‘BATT’ legend first comes
on. Again care should be taken not to activate the TACLITE™ during
battery replacement, if the TACLITE™ is activated it will significantly
reduce the time that the EMC-20H allows for battery changes.
If the batteries are allowed to discharge too low, or if removed for too
long, the EMC-20H may enter a state where it will not turn on even with
new batteries. If this occurs, remove the batteries and allow the unit to
set for 30 minutes and then install fresh batteries. This procedure could
affect the internal Time of Day Clock’s settings and these settings should
be verified via the Analyst®P.C. Interface.
CAUTION!!! COMPLETE LOSS OF BATTERY POWER MAY CAUSE
ALL PREVIOUS DIVE NITROGEN LOADING TO BE LOST. THIS MAY
AFFECT NITROGEN CALCULATIONS ON NEAR-FUTURE DIVES.
AFTER A BATTERY CHANGE, CONFIRM THAT NO-
DECOMPRESSION TIME DATA IS REASONABLE DURING PRE-DIVE
PREDICTION MODE. DIVE-OF-DAY NUMBER GOING TO ZERO
IMMEDIATELY AFTER CHANGING BATTERIES IS ANOTHER
INDICATION OF A LOSS OF NITROGEN LOADING.
CAUTION!!! Putting the battery(s) in backwards may cause
permanent damage to the unit and will VOID the Warranty.
ASSISTANCE, REPAIR & MAINTENANCE: The Cochran EMC-20H
does not require an Annual Maintenance, but if you suspect that your
EMC-20H is not operating correctly, please contact our Customer
Support Department in the USA for assistance at 972.644.6284 or FAX
details to 972.644.6286 or E-mail details to [email protected].
Most problems can be resolved without returning the unit. The unit may
also be returned to the place of purchase and request the dealer to
contact us. If this is not possible or is inconvenient due to a change in
location, contact us for the name of the nearest Team Cochran
Authorized Dealer.
•NEVER TEST OR SUBJECT THE PRODUCT TO PRESSURIZED AIR!
(Voids Warranty)
•NEVER REMOVE THE LENS FROM THE UNIT! (Voids Warranty)
•ONLY USE FRESH WATER TO CLEAN UNIT! NEVER USE SOLVENTS!
(Voids Warranty)
•DO NOT USE A SCREWDRIVER TO REMOVE BATTERY CAP! (Voids
Warranty)
•ALWAYS KEEP FRESH ENERGIZER®BRAND BATTERIES INSTALLED!
•LUBRICATE BATTERY ENDS WITH THIN FILM OF SILICONE GREASE!
REPLACEMENT PARTS:
Batteries (2) Battery Cap O-rings
Battery Cap Assembly Pins (2) Replacement
Wrist Strap (long Gray) Wrist Strap (long, black)
Retractor Only Retractor with Compass
Lens Protector (Pkg. of 3)