A&D 2 Plus - Manual (Page 3)

ACTIVATING THE COMPUTER
One of the nice features of the M2+ is that it automatically turns on
and starts working when you enter the water. However, its a good
idea to manually turn on the computer before a series of dives to
make sure it is working properly and to check the battery power. To
manually switch on the M2+, touch contacts A and D. Check the
display to make sure all the display elements are lit.
The M2+ is now in Ready Mode. The computer switches to Dive
Mode after entering the water and submerging below four feet. The
depth indication may be delayed for a few seconds.
Note: After three minutes of inactivity, the M2+ screen goes blank. This
indicates that the computer is in Sleep Mode. To "wake up" the
computer, touch contacts A & D.
CHECKING THE BATTERY POWER
FUNCTIONS DURING THE DIVE
CURRENT DEPTH
Current depth is displayed in one-foot increments down to a
maximum of 330 feet. When the depth is two feet or less, the depth
display is replaced with three dashes.
Note: Depth measurement is based on freshwater. When diving is salt
water, the depth displayed will be slightly greater than the actual depth,
depending on the salinity of the water.
Current depth display at
2 feet or shallower
Current depth display
at 100 feet
DIVE TIME
Dive time, which is displayed in minutes, is the
amount of time spent below a depth of 4 feet. While
the dive time is running, the colon to the right of the
number flashes in one-second intervals. Maximum
dive time displayed is 199 minutes.
Note: If a dive lasts longer than 199 minutes, dive
time will roll over to 0 minutes.
Dive time display
Maximum depth
display
MAXIMUM DEPTH
Maximum depth is the deepest depth reached
during the dive. It is only displayed when the
actual depth is more than three feet shallower
than the maximum depth.
ASCENT RATE
The optimal ascent rate varies between 23
and 67 ft/min. depending on the depth.
Ascent rate is displayed as a percentage of
the allowable ascent rate (rounded to the
nearest 10 %). For example, if the allowable
ascent rate at the current depth is 67 ft/min,
and you ascend at 33 ft/min, the ascent rate
will display 50%. If you ascend at 67 ft/min
the ascent rate will show 100%.
WARNING: The prescribed ascent
rate must be observed at all times!
Exceeding the prescribed ascent
rate can lead to microbubble
formation which can lead to
serious injury or death due to
decompression sickness.
Ascent Rate Display
If the ascent rate is 100% or more, the arrow appears. If the ascent
rate exceeds 140%, the arrow starts flashing. Also, an acoustic alarm
sounds when ascent rate is 110% or greater. The intensity of the
alarm increases as the percentage over the allowable rate increases.
Below is a summary of the ascent warnings.
Some Notes on ascent rate:
- The M2+ may require a decompression stop due to an improper
ascent rate, even if you stay within the no-stop limits.
- Decompression time necessary for the prevention of microbubbles
can increase greatly if the ascent rate is exceeded.
- At great depth, ascending too slowly may cause heightened satura-
tion of tissues and increase both decompression time and total
ascent time. At shallow depth, a slow ascent may shorten decom-
pression time because the tissues are desaturating during a shallow,
slow ascent.
- Excessive rates of longer periods are entered in the dive computer's
memory
You can manually check the battery
power of the M2+. While in Ready
Mode or Surface Mode, touch
contacts A&D. The word "bat" will
be displayed along with the battery
power. Battery power is given as a
percentage, with 99% being the
highest percentage displayed. It is a
good idea to check the battery
power before you start a series of
dives.