Shearwater Perdix 2 setup guide

Also covers: Shearwater Perdix 2

Two-button (MENU left, SELECT right) colour-screen computer with Air, Nitrox, 3 GasNx and Gauge recreational modes (plus technical modes). Uses a replaceable AA-size battery; vibration alerts, no beeper.

Buttons

Button	Where	What it does
`MENU`	left side of the housing	Open the menu; move to the next item; while editing, change the value
`SELECT`	right side of the housing	Step through info screens; run a command or start editing; while editing, save the value

Turn on / wake

Press MENU and SELECT at the same time to turn the computer on.
Press togetherMENUPress togetherSELECT
Manual p. 7
A start-up screen shows for about 2 seconds, then the main screen appears.
Manual p. 6
It also switches on by itself about 0.9 m / 3 ft underwater, but do not rely on this. Turn it on yourself before every dive to check battery and settings.
Manual p. 6
Press MENU on the main screen to open the menu. MENU moves to the next item; SELECT runs the item or starts editing.
PressMENUPressSELECT
Manual p. 7
To leave a menu, stop pressing buttons. After 10 seconds it returns to the main screen; saved values stay, half-finished edits are lost.
Manual p. 47
To switch off on the surface, press MENU and, at Turn Off (first item), press SELECT. Turn Off is hidden during a dive and for 1 minute after it (default).
PressMENUPressSELECT
Manual p. 48

Date and time

System Setup cannot be opened during a dive (p. 53).

On the surface, press MENU repeatedly until System Setup appears, then press SELECT.
PressMENUPressSELECT
Manual p. 47
Press MENU until the System Setup page (date and clock) appears, then press SELECT.
PressMENUPressSELECT
Manual p. 60
On the Date line, press SELECT to start editing. Press MENU to change the value and SELECT to save it; repeat for each part.
PressSELECTPressMENU
Manual p. 60
Press MENU to move to the Clock line and set it the same way. You can choose AM/PM or 24-hour time.
PressMENUPressSELECT
Manual p. 60
The clock also updates whenever the computer connects to Shearwater Cloud Desktop or Mobile.
Manual p. 67

Units (m/ft, °C/°F)

Press MENU until System Setup appears and press SELECT. Press MENU until Display Setup appears and press SELECT.
PressMENUPressSELECT
Manual p. 59
On Depth Units, press SELECT, press MENU to choose Meters or Feet, then press SELECT to save.
PressSELECTPressMENU
Manual p. 59
Press MENU to Temp Units, press SELECT, press MENU to choose °C or °F, then press SELECT to save.
PressMENUPressSELECT
Manual p. 59
Depth and temperature units are set separately.
Manual p. 59

Water type (salt/fresh)

Press MENU until System Setup appears and press SELECT. Mode Setup is the first page; press SELECT to open it.
PressMENUPressSELECT
Manual p. 54
Press MENU to the Salinity line, press SELECT, press MENU to choose Fresh, EN13319 or Salt, then press SELECT to save.
PressMENUPressSELECT
Manual p. 54
EN13319 (between fresh and salt) is the default. This setting changes only the depth shown, not the decompression calculation.
Manual p. 54

Dive mode (Air / Nitrox / Gauge)

Mode can only be changed on the surface (System Setup is not available during a dive, p. 53).

Press MENU until System Setup appears and press SELECT. Mode Setup opens first; press SELECT.
PressMENUPressSELECT
Manual p. 54
On the Mode line, press SELECT, press MENU to choose Air, Nitrox, 3 GasNx, OC Tec, CC/BO or Gauge, then press SELECT. 3 GasNx is the default.
PressSELECTPressMENU
Manual p. 54
For one tank of air choose Air. For one tank of nitrox choose Nitrox. Shearwater recommends these simple modes for new divers.
Manual p. 8
Gauge is a bottom timer: depth and time only, no decompression information.
Manual p. 10
Changing to or from Gauge clears the tissue (nitrogen) data. Plan repeat dives with this in mind.
Manual p. 54
There is no lock-out for missed safety or deco stops; the computer warns you instead.
Manual p. 28

Nitrox O₂% and ppO₂ limit

The manual does not say that the O2 % resets to 21% by itself.

Set the Mode to Nitrox (see Dive mode). Nitrox mode is for one gas up to 40% O2.
Manual p. 10
In Mode Setup, press MENU to Gas O2%, press SELECT, press MENU to change the value to your analysed %, then press SELECT.
PressMENUPressSELECT
Manual p. 54
Press MENU to MOD PPO2. The default is 1.40; only change it if your instructor tells you to. The MOD for the gas is shown below it.
PressMENU
Manual p. 54
In Air mode the O2 is fixed at 21%.
Manual p. 54
In Nitrox mode the gas can also be changed with Define Gas in the main menu, even during a dive.
Manual p. 49

Conservatism / personal setting

Press MENU until System Setup appears and press SELECT. Press MENU until Deco Setup appears and press SELECT.
PressMENUPressSELECT
Manual p. 55
On Conservatism, press SELECT, press MENU to choose Low, Med or High, then press SELECT. Med is the default.
PressSELECTPressMENU
Manual p. 55
The manual lists Low 45/95, Med 40/85, High 35/75. Since firmware V102 the presets are Low 50/95, Med 50/85, High 50/75. Check the GF shown on screen.
Manual p. 55; Release Notes V102 p. 1
The second number (GF High) controls your no-stop time: a lower number is more conservative and gives shorter no-stop times.
Manual p. 29
A Custom GF setting also exists. Do not use it unless you understand gradient factors.
Manual p. 55
In Deco Setup you can also set the safety stop: Off, 3, 4 or 5 minutes, Adapt, or CntUp (count up).
Manual p. 55

Altitude

Not available on this computer

There is no altitude setting to change: in recreational modes altitude is fixed to Auto and the computer adjusts for surface pressure automatically (p. 59).

Audible alarms (depth / time)

The manual describes on-screen and vibration alerts only, no beeper. Vibration works only with a 1.5V lithium or 3.7V Li-ion battery (p. 23).

Press MENU until System Setup appears and press SELECT. Press MENU until Alerts Setup appears and press SELECT.
PressMENUPressSELECT
Manual p. 58
On Depth, press SELECT, press MENU to switch it on and change the depth, and press SELECT to save. Default: 40 m.
PressSELECTPressMENU
Manual p. 58 (default p. 24)
Press MENU to Time and set it the same way. Default: 60 minutes, but switched off.
PressMENUPressSELECT
Manual p. 58 (default p. 24)
Low NDL warns when no-stop time gets short (default 5 minutes). Vibration on/off is the last line.
Manual p. 58 (default p. 24)
Before diving, open Dive Setup and run Test Vibration to check you can feel it.
Manual p. 52
When an alert appears, press either button to clear it.
Manual p. 22

Reading the log after a dive

Dive Log is only available on the surface (p. 52).

On the surface, press MENU until Dive Log appears, then press SELECT.
PressMENUPressSELECT
Manual p. 47
At Display Log, press SELECT to see the list of dives.
PressSELECT
Manual p. 52
Press MENU to move to a dive and SELECT to view it.
PressMENUPressSELECT
Manual p. 52
The log shows max and average depth, dive number, date, start and end time, dive length, temperatures, mode, surface interval, GF and CNS.
Manual p. 52
The depth profile is drawn in blue; deco stops are shown in red.
Manual p. 52

Battery

On the surface, check the battery icon on the main screen: blue is OK, yellow means change soon, red means change now.
Manual p. 12
Press SELECT on the main screen to step through the info screens; one shows the battery voltage and type.
PressSELECT
Manual p. 21
If LOW BATTERY INT appears, replace the battery before diving.
Manual p. 25
It uses one AA-size battery. Open the cap with a large coin, put the new battery in positive end first, and close the cap.
Manual p. 66
After a change, check the battery type shown on screen and correct it if needed. Shearwater recommends 1.5V lithium batteries.
Manual p. 66
Settings are kept when you change the battery. Check the clock if the battery was out for more than a few minutes.
Manual p. 67

What the main screen shows

Top left: current depth. Next to it: dive time in minutes and seconds. On the surface this shows the surface interval and battery icon.
Manual p. 11
Ascent rate arrows: white under 9 m (30 ft) per minute, yellow up to 18 m (60 ft) per minute, flashing red above that.
Manual p. 12
NDL is the no-stop time left in minutes. It turns yellow when 5 minutes or less are left.
Manual p. 13
Below 11 m (35 ft) a safety stop counter appears. It counts down between 2.4 and 8.3 m (7–27 ft).
Manual p. 27
If NDL reaches 0, the stop depth and time replace the safety stop. Go to that stop depth and wait.
Manual p. 13
Bottom row: current gas, max depth, time of day and temperature. Press SELECT for more data, MENU to return.
PressSELECTPressMENU
Manual p. 11

Pre-dive check

Tick each item before you get in the water.

Dive mode is Air or Nitrox as planned (not 3 GasNx or Gauge unless intended).
Nitrox: Gas O2% matches your analysed tank and MOD PPO2 is 1.40 unless told otherwise.
Salinity matches the dive site (Fresh, EN13319 or Salt).
Conservatism is the level your instructor wants.
Battery icon is blue, with no low-battery warning.
Depth and time alerts are set; vibration works (Test Vibration).
Depth units (m or ft) are the ones you expect.
Turn the computer on yourself before the dive; do not rely on auto-on.