Cressi Neon setup guide

Two-button watch-style dive computer (Air, Nitrox with two gases, Free, Gauge). The manual is shared with the Cartesio and Goa; the Neon works the same as the Cartesio in this guide. Rental note: check it is not locked (padlock) before diving.

Buttons

Button	Where	What it does
`▲ / SEL`	right side, upper button	Short press: scroll up / increase. Long press (SEL): enter a function or confirm. Hold in dive or stopwatch mode: backlight.
`▼ / ESC`	right side, lower button	Short press: scroll down / decrease. Long press (ESC): exit back to the TOP menu. Long press in NITROX dive: gas change (MIX).

Turn on / wake

There is no off button: it stays in watch mode. The dive function can be locked with MODE-S OFF (padlock); see Dive mode (page 9).

The Neon is always on in watch mode; the TOP screen shows time and date.
Manual p. 7-8
Press ▼ from the TOP screen to go to the DIVE (pre-dive) screen before every dive.
Press▼ / ESC
Manual p. 19
If you forget, it starts dive calculations by itself within 20 seconds once you pass 1.2 m depth.
Manual p. 19
Use ▲ / ▼ to scroll the main menu: CHRONO, MODE-S, LOG, DIVE-S, TIME-S, PLAN, SYSTEM, DIVE.
Press▲ / SELPress▼ / ESC
Manual p. 8
Hold ESC (▼) to leave a menu and go back to the TOP screen.
Hold▼ / ESC
Manual p. 8

Date and time

Scroll with ▲ / ▼ to TIME-S, then hold SEL to enter.
Press▲ / SELPress▼ / ESCHold▲ / SEL
Manual p. 16
Use ▲ / ▼ to move through: AL. (alarm clock), H24/H12, hour, minutes, d-m/m-d, day, month, year, T2.
Press▲ / SELPress▼ / ESC
Manual p. 16
Hold SEL on the item you want, then change it with ▲ / ▼.
Hold▲ / SELPress▲ / SELPress▼ / ESC
Manual p. 16
Hold SEL to confirm, then hold ESC to exit.
Hold▲ / SELHold▼ / ESC
Manual p. 16

Units (m/ft, °C/°F)

The manual names the UNITS screen but gives no step list for it; these steps use the general button rules on pages 7-8. Depth and temperature units change together (page 7).

Scroll with ▲ / ▼ to SYSTEM, then hold SEL. The functions PC, UNITS, HIST, INFO, AL.SP and T.ERASE are inside.
Press▲ / SELPress▼ / ESCHold▲ / SEL
Manual p. 17
Scroll with ▲ / ▼ to UNITS and hold SEL to enter it.
Press▲ / SELPress▼ / ESCHold▲ / SEL
Manual p. 8, 17
Change between metric (m, °C) and imperial (ft, °F) with ▲ / ▼, then hold SEL to confirm and hold ESC to exit.
Press▲ / SELPress▼ / ESCHold▲ / SELHold▼ / ESC
Manual p. 7-8

Water type (salt/fresh)

Not available on this computer

There is no salt/fresh setting: depth is calibrated for sea water, and fresh-water depths read about 3% lower (page 32).

Dive mode (Air / Nitrox / Gauge)

Factory setting is AIR (page 29).

Scroll with ▲ / ▼ to MODE-S and hold SEL. The current mode flashes.
Press▲ / SELPress▼ / ESCHold▲ / SEL
Manual p. 9
Choose with ▲ / ▼: AIR, EAN (Nitrox), FREE (apnea), GAGE (depth gauge) or OFF (padlock, dive function off).
Press▲ / SELPress▼ / ESC
Manual p. 9
Hold SEL until you hear the confirmation beep, then hold ESC to go back.
Hold▲ / SELHold▼ / ESC
Manual p. 9
If you see the padlock icon, the computer is blocked: unlock it in MODE-S before the dive. It cannot be unlocked underwater.
Manual p. 9, 19
Warning: after a GAGE dive there are no decompression calculations for 48 hours. After a FREE dive, AIR or EAN dives are blocked for 24 hours.
Manual p. 28-29

Nitrox O₂% and ppO₂ limit

Factory values: AIR, PO2 1.4 bar, 21% O2 (page 19). PO2 can only be changed at the surface (page 23).

Set MODE-S to EAN first (see Dive mode).
Manual p. 9, 13
Scroll with ▲ / ▼ to DIVE-S and hold SEL. Scroll to the PPO2 GAS1 screen.
Press▲ / SELPress▼ / ESCHold▲ / SEL
Manual p. 13, 15
Hold SEL so the value flashes, set 1.2–1.6 bar with ▲ / ▼, and hold SEL until it beeps.
Hold▲ / SELPress▲ / SELPress▼ / ESC
Manual p. 15
Scroll to %O2 GAS1, hold SEL, set the analysed O2 % (21–50%) with ▲ / ▼, and hold SEL until it beeps.
Press▲ / SELPress▼ / ESCHold▲ / SEL
Manual p. 3, 15
GAS2 (21–99%) is a second gas you switch to by hand during ascent. Set PPO2 GAS2 and %O2 GAS2 the same way only if you carry it.
Press▲ / SELPress▼ / ESCHold▲ / SEL
Manual p. 15, 22
Hold ESC to exit. Check the max depth shown for your mix on the DIVE screen.
Hold▼ / ESC
Manual p. 15, 19
The O2 % and PO2 stay at the last values set; they do not reset by themselves. Check them before every dive.
Manual p. 15, 21

Conservatism / personal setting

Scroll with ▲ / ▼ to DIVE-S and hold SEL, then scroll to the SF screen.
Press▲ / SELPress▼ / ESCHold▲ / SEL
Manual p. 13-14
Hold SEL and choose SF0, SF1 or SF2 with ▲ / ▼.
Hold▲ / SELPress▲ / SELPress▼ / ESC
Manual p. 14
Hold SEL until you hear the confirmation beep.
Hold▲ / SEL
Manual p. 14
SF0 is the factory setting (off). SF1 and SF2 make the dive more conservative; use them when personal risk factors apply.
Manual p. 5, 14

Altitude

Altitude is not detected automatically; set it before diving above sea level (page 14).

Scroll with ▲ / ▼ to DIVE-S and hold SEL, then scroll to the ALT screen.
Press▲ / SELPress▼ / ESCHold▲ / SEL
Manual p. 13-14
Hold SEL and choose the level with ▲ / ▼: no mountain 0–700 m, 1 = 700–1500 m, 2 = 1500–2400 m, 3 = 2400–3700 m.
Hold▲ / SELPress▲ / SELPress▼ / ESC
Manual p. 14
Hold SEL until you hear the confirmation beep.
Hold▲ / SEL
Manual p. 14

Audible alarms (depth / time)

The manual lists user-set alarms only for FREE mode. It explains how to switch the ascent alarm off (AL.SP), but not how to switch it back on (page 18).

In AIR and EAN, audible alarms are built in: fast ascent, PO2 limit, CNS oxygen, 3 minutes of no-deco left, deep stop and missed deco stop.
Manual p. 23-26
Look for a crossed-out loudspeaker icon: it means the fast-ascent alarm was switched off in SYSTEM → AL.SP (instructor use only).
Manual p. 18
User-set depth and dive-time alarms exist only in FREE (apnea) mode: in DIVE-S choose DEPTH or DIVE-T, hold SEL, set with ▲ / ▼, hold SEL.
Hold▲ / SELPress▲ / SELPress▼ / ESC
Manual p. 15-16

Reading the log after a dive

Stores up to 50 dives of each type (air/EAN, free, gauge); the log cannot be erased (page 10).

Scroll with ▲ / ▼ to LOG and hold SEL. The newest dive is shown first (date, start time, log number).
Press▲ / SELPress▼ / ESCHold▲ / SEL
Manual p. 10
Hold SEL to open that dive's data, then scroll its pages with ▲ / ▼.
Hold▲ / SELPress▲ / SELPress▼ / ESC
Manual p. 10-11
AIR log: SF, dive time, max and average depth, minimum temperature, altitude and PO2-alarm icons, max PO2 set.
Manual p. 10-11
EAN log also shows the PO2 and O2 % for GAS1 and, on page 3, GAS2.
Manual p. 11-12
Hold ESC to go back to the TOP screen.
Hold▼ / ESC
Manual p. 8

Battery

A steady battery icon means it still works, but change the battery soon.
Manual p. 31
A flashing battery icon means the dive functions are disabled. Do not dive until the battery is changed.
Manual p. 31
The battery is a CR2450 3 V. The cover is held by two screws on the back.
Manual p. 31-32
Do not change it during desaturation: nitrogen data, time and date are lost; then do not dive for 48 hours. Reset time and date.
Manual p. 31

What the main screen shows

DIVE (pre-dive) screen: mode (AIR/NITROX/GAGE/FREE), max PO2, max depth for the gas and, in NITROX, O2 % per gas.
Manual p. 19
During a dive: dive time, current depth, max depth, no-deco time, temperature, ascent rate, altitude, SF and CNS oxygen bar.
Manual p. 20
Press ▲ during the dive for max PO2, gas or O2 %, maximum allowed depth and the time.
Press▲ / SEL
Manual p. 20, 22
Hold ▲ (SEL) underwater to switch on the backlight for a few seconds.
Hold▲ / SEL
Manual p. 7-8
After the dive: surface interval (SURF.T), no-fly time (DESAT) with NO FLY icon, last max depth and dive time.
Manual p. 29-30

Pre-dive check

Tick each item before you get in the water.

Battery icon is not flashing.
No padlock icon: MODE-S is AIR or EAN, not OFF.
DIVE screen shows the planned mode; no GAGE dive in the last 48 h and no FREE dive in the last 24 h.
In EAN, O2 % for GAS1 matches the analysed cylinder.
Max PO2 is the planned value (factory 1.4 bar).
Safety factor (SF0/SF1/SF2) is set as the diver wants.
Altitude level matches the dive site.
No crossed-out loudspeaker icon (ascent alarm on).
Computer set to the DIVE screen before entering the water.