WatchGas NEO User manual

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NEO Photoionization Detector
User Manual
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Detection NEO Photoionization Detector User Manual
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Contents
Contents 2
Description 3
Warning 3
Caution 3
1 Product Overview 4
2 Display 4
3 Charging a Lithium-ion Battery 5
3.1 Low Voltage Warning 5
3.2 Clock Battery 6
3.3 Data Protection While Power is O 6
4 Instrument Operation 6
5 Basic User Mode 6
5.1 Turning The Instrument On 6
5.2 Turning The Instrument O 7
5.3 User Mode Summary 7
5.4 Integrated Sampling Pump 8
5.4.1 Pump Status 8
5.5 External Water Trap Filters 8
5.6 Alarm Signals 8
5.6.1 Alarm Signal Summary 9
5.6.2 Pre-Set Alarm Limits & Calibration Concentrations 9
5.6,3 Testing the alarms 9
5.7 Display Backlight 9
5.8 Data Logging 9
5.9 Man Down Alarm 10
5.10 Wireless 10
6 Cong Mode 10
6.1 Entering And Exiting The Cong Mode 10
6.2 Making Changes In Cong Mode 10
6.2.1 Selection From a List 11
6.2.2 Entering Numerical Values 11
6.3 Cong Mode Menus 12
7 Using Cong Mode Modus 14
7.1 Calibration 14
7.1.1 Calibration Set-up 14
7.1.2 Zero Calibration 15
7.1.3 Span Calibration 15
7.1.4 Set Calibration Gas 16
7.1.5 Set Span Value 16
7.2 Measurement 17
7.2.1 Measurement Unit 17
7.2.2 Measurement Gas 17
7.3 Alarm Settings 18
7.3.1 Change Alarm Limits 18
7.3.2 Alarm Mode 19
7.3.3 Alarm Settings 19
7.3.4 Comfort Beep 19
7.3.5 Man Down Alarm 20
7.4 Datalog 20
7.4.1 Clear Datalog 21
74.2 Set Datalog Interval 21
7.5 MNT (Monitor) Setup 21
7.5.1 Date And Time 21
7.5.2 Display 21
7.5.3 Pump Speed 22
7.5.4 Set Pump Stall 22
7.55 3-Point Calibration 23
7.5.6 Rolling Graph 23
7.5.7 Real Time Data 23
7.5.8 Language 24
7.5.9 Self-Zeroing 24
7.5.10 Wireless 24
8 Computer Interface with WatchGas Suite 25
8.1 Connecting And Conguring 25
8.2 Retrieve Datalog 25
9 Maintanance 26
9.1 Lamp Cleaning Or Changing 26
9.2 Sensor Cleaning 27
10 Troubleshooting 28
11 Specications 29
12 Limited Warranty 30

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Description
The NEO is one of the most advanced handheld monitors available for ppb (parts per billion) VOC
(Volatile Organic Compound) detection. The NEO oers several models from the most sensitive 1 ppb
to a high range up to 15000 ppm for dierent applications and user selections. New designs of the
photo-ionization detector (PID) and ultraviolet (UV) lamp provide outstanding sensitivity, stability
and reproducibility. Options include real time data monitoring with a built-in wireless modem using
WatchGas Suite application software.
Warning
• This manual must be carefully read by all individuals who have or will have the responsibility of using,
maintaining, or servicing the product. The product performs as designed only if it is used, maintained, and
serviced in accordance with the manufacturer’s instructions.
• For safety reasons, this equipment must be operated and serviced by qualied personnel only. Read and
understand the instruction manual completely before operating or servicing the instrument.
• Service work performed by unauthorized personnel voids all warranties, especially those concerning
intrinsic safety.
• The user should understand how to set the correct parameters and interpret the obtained results.
• Do not use the product if a part is damaged or defective. Replace a damaged or defective instrument
immediately.
• Substitution of components with non-original parts voids all warranties, especially those concerning
intrinsic safety.
• Batteries may only be replaced by WatchGas service centers.
• Use only WatchGas battery pack M011-3002-W00.
• Recharge batteries only in non-hazardous locations only.
• Do not mix old and new batteries or batteries from dierent manufacturers.
• Use USB/PC communication in a non-hazardous location only.
• Static Discharge Hazard: only clean the outside with a damp cloth in non-hazardous locations only.
• The correct functioning of the instrument should be tested before each day’s use, including testing the
sensor by exposing the instrument to a bump test gas that triggers the alarm.
• Check that a clean inlet lter is in place. A contaminated lter can alter the detected concentrations and
impair correct functioning of the instrument. Damage caused by dirt and water entering through the inlet is
not covered by the warranty.
• Check that gas inlet and outlet ports are clean and free of obstructions.
• Check that the buzzer port is free of obstructions
Caution
• Never operate the instrument when the cover is removed.
• Remove instrument cover and sensor module in non-hazardous locations only.

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2. Display
The LCD display provides visual feedback that includes the reading, pump, Man Down, time, battery
condition, and other functions. The display shows the following information:
1. Product Overview
The instrument’s user interface consists of the LCD
display, Alarm LEDs, an alarm transducer, and four
keys. The keys are:
Esc
Ent
OK
Esc
Ent
OK
EscEnt
OK
EscEnt
OK
Esc/Left key
Enter/Right Key
OK/Up Key
Down/Mode Key
INLET FILTER
LCD DISPLAY
GAS OUTLET
OK / UP KEY
ESC / LEFT KEY
MICRO USB PORT
SENSOR CAP
ALARM LEDS
RIGHT KEY
ENTER KEY
BUZZER PORT
DOWN/MODE KEY
RUBBER BOOT
MAN DOWN
STATUS
PUMP STATUS
CALIBRATION//
BUMP DUE
BATTERY STATUS
DATALOG STATUS
READING AND MEASURING
UNIT
LAMP STATUS
TIME
GAS NAME AND
CORRECTION FACTOR
TEMPERATURE
LCD DISPLAY

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3.Charging a Lithium-Ion Battery
The screen displays a battery icon from empty (no bars) to fully charged (3 bars).
To charge the instrument:
1. Insert the Micro-USB connector into the charging port at the bottom of the instrument.
2. Insert the USB connector into:
a) A free USB port in a laptop or computer.
b) The supplied AC/DC adapter.
3. Make sure the computer provides power to the USB port, or connect the AC/DC adapter to a
power outlet.
The 3 bars of the battery icon on the instrument’s display are animated, indicating charging
progress.
When the battery is fully charged:
• The battery icon is no longer animated and shows a full battery
• The message ‘Fully Charged’ is displayed.
USB cable P/N M-011-3003-W00 is required for a PC to recognize the instrument and communicate
with WatchGas Suite.
Notes:
Always fully charge the battery before using the instrument.
Please use the original WatchGas charger.
For PC communication with WatchGas Suite, WatchGas USB cable P/N M-011-3003-W00 is required.
Item Description
Gas information Shows the measurement gas and its correction factor
Reading Concentration of gas measured by the instrument
Calibration/Bump Due Indicates if calibration or bump status is OK or not
Pump Status Indicates whether the pump is working or blocked
Man Down Status Indicates if Man Down alarm is on
Lamp Status Indicates if the lamp is on or not
Datalog Status Indicates whether datalog is on or o
Battery Status Indicates battery capacity in 3 bars
Time Indicates current time
Temperature Indicates current temperature
Warning
To reduce the risk of ignition of hazardous atmospheres, recharge and replace batteries only
in areas known to be non-hazardous. Use only WatchGas rechargeable lithium battery part
number: M011-3002-W00.

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3.1 LOW VOLTAGE WARNING
When the battery’s charge falls below a pre-set voltage, the instrument warns you by beeping
once and ashing once every minute, and the battery icon blinks on and o once per second.
Turn o the instrument within 10 minutes and recharge the battery.
3.2 CLOCK BATTERY
An internal clock battery is mounted on one of the instrument’s printed circuit boards. This long-life
battery keeps settings in memory from being lost whenever the Li-ion battery or alkaline batteries are
removed. The backup battery lasts approximately ve years, and must be replaced by an authorized
WatchGas service technician. It is not user-replaceable.
3.3 DATA PROTECTION WHILE POWER IS OFF
When the instrument is turned o, all the current real-time data, including TWA, STEL and peak
concentrations are erased. Logged data are stored in non-volatile memory. Logged data is secure,
even when the battery is disconnected.
4. Instrument Operation
The NEO gives real-time measurements and activates alarm signals whenever the detected
concentrations exceed preset alarm limits.
The instrument starts up in Basic User Mode. In Basic User Mode, no changes can be made to its
operation.
In Conguration Mode, settings can be changed. Conguration Mode is password protected. Via the
WatchGas Suite software, Conguration Mode can be made inaccessible. See also 6.2.2.
Notes:
• Part of WatchGas Quality Assurance is a full factory calibration and pre-set alarm limits.
• Prior to factory shipment, the instrument is preset with default alarm limits and the sensor is pre-calibrated
with standard calibration gas. However, the instrument should be tested and the calibration veried before the
rst use.
• Check the alarm limits before using the instrument.
• Place an inlet lter before using the instrument.
• Charge the battery fully before using the instrument.
5. Basic User Mode
5.1 TURNING THE INSTRUMENT ON
Press and hold
EscEnt
OK
until the display, buzzer and alarm LEDs turn on, then release.
After that:
• The display shows rmware version and serial number.
• The instrument performs a number of self-tests for the correct functioning of the pump, clock,
datalog, motion sensor and PID sensor.
• The instrument shows sensor information and instrument conguration.
• The display shows the readout screen.
The instrument is now fully functional and ready for use.

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Note:
If the WatchGas logo does not appear rst on start-up, a problem might have occurred.
Contact WatchGas Technical Support.
5.2 TURNING THE INSTRUMENT OFF
1. Press and hold
EscEnt
OK
A 5-second countdown is displayed, followed by“Unit o...”.
2. Release
EscEnt
OK
.
5.3 USER MODE SUMMARY
The instrument starts up into Basic User Mode. The readout screen shows the detected concentration
in real time and various information about the current status of the instrument.
Use
EscEnt
OK and
EscEnt
OK
to cycle through the main menu screens. If you do not press a key for 60 seconds,
the display returns to the readout screen automatically.
FLOW CHART FOR BASIC USER MODE
The example shown in this illustration is a ow chart of the NEO ppb.

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5.4 INTEGRATED SAMPLING PUMP
The instrument is equipped with an integrated diaphragm sampling pump. It has three ow rate
settings, with ow ranging from 250 ml/min to 400 ml/min with an inlet lter attached.
As contamination builds up in the lter, the ow rate decreases.
Note:
• Always use the instrument with a clean inlet lter in place. Contamination can build up in and clog up the
pump, decreasing ow rate and increasing the risk of pump failure.
• Always change the inlet lter when it is visibly dirty.
• Make sure the inlet and outlet are free of obstructions before and during use.
Note:
Response time of the instrument drops with approximately 1 second for every 0.9 meters (3 ft) of tubing.
5.4.1 PUMP STATUS
During normal operation, the pump icon alternately shows inow and outow. When a
pump failure or obstruction occurs, the pump alarm activates and the pump stall icon
blinks on and o. Clear the obstruction and press
Esc
Ent
OK
to restart the pump.
5.5 EXTERNAL WATERTRAP FILTERS
An external lter is mandatory to prevent moisture and dirt entering the instrument. Moisture and dirt
in the instrument can result in wear on the pump, false readings, and/or pump stalling.
To install the external lter:
1. Unscrew the old or contaminated lter.
2. Take a new inlet lter from the packaging.
3. Screw the new lter to the instrument’s inlet probe using the Luer connection.
5.6 ALARM SIGNALS
During operation, the gas concentration is continuously compared with the alarm limits. If the
concentration exceeds any of the pre- set limits, the buzzer and red ashing LED are activated to warn
of the alarm condition. In addition, the instrument alarms when the:
• Battery voltage falls below a preset voltage level
• UV lamp is o
• Pump stalls

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Message Condition Alarm Signal
HIGH Gas exceeds‘High Alarm’limit 3 beeps/ashes per second
OVR Gas exceeds measurement range 3 beeps/ashes per second
MAX Gas exceeds electronics’ maximum range 3 beeps/ashes per second
LOW Gas exceeds‘Low Alarm’limit 2 beeps/ashes per second
TWA Gas exceeds‘TWA’ limit 1 beep/ash per second
STEL Gas exceeds‘STEL’ limit 1 beep/ash per second
Pump icon ashes Pump stall 3 beeps/ashes per second
Lamp PID lamp o 3 beeps/ashes per second plus ‘Lamp’
message
Battery icon ashes Low battery 1 ash, 1 beep per minute plus battery icon
ashes
CAL Calibration failed, or is overdue 1 beep/ash per second
NEG Calibration error results in a negative
reading
1 beep/ash per second
5.6.1 ALARM SIGNAL SUMMARY
Cal Gas Cal Span Unit Low High TWA STEL
Isobutylene 10 ppm 50 100 10 25
5.6.2 PRESET ALARM LIMITS & CALIBRATION CONCENTRATIONS
The instrument is factory calibrated with standard calibration gas, and is programmed with default
alarm limits. For example, on the NEO PPM, the default values are:
A 3-point calibration is done:
1. At 0 ppm in 99.99% vol N2
2. At concentration 10 ppm isobutylene
3. At concentration 100 ppm isobutylene
5.6.3 TESTING THE ALARMS
The alarm can be tested whenever the readout screen is shown. Press
Esc
Ent
OK
, and the audible and visible
alarms are tested.
5.7 DISPLAY BACKLIGHT
The LCD display is tted with LED illumination to improve readability in poor lighting conditions.
Illumination turns on automatically in poor light. The settings for display illumination can be changed
in Cong Mode or through WatchGas Suite.
5.8 DATA LOGGING
By default, the instrument stores the detected concentration every 60 seconds.
The datalog icon is displayed when datalogging is on.
A 60 second interval allows for up to a year of data storage. The data is stored in non-volatile memory
for download to a PC. The data is retained, even when the instrument is turned o or the battery is
removed.
Data is organised in events, with a new event created each time the instrument is turned on, a
conguration parameter is changed or datalogging is interrupted. Every event includes User ID, Site ID,
serial number, last calibration date and the alarm limits.

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5.9 MAN DOWN ALARM
The Man Down Alarm is a potentially lifesaving safety feature of the NEO. The Man Down Alarm
function assumes that when the instrument is motionless, something could be wrong with its user.
When the instrument is motionless for a pre-set time, the instrument warns the user that Man Down
Alarm is triggered. The user can cancel the alarm. When the user does not cancel the alarm, the Man
Down Alarm is activated after a pre-set period. The Man Down Alarm activates the buzzer and LEDs to
enable rescuers to track the user.
1. If the instrument is connected to a wireless network, a remote alarm is triggered, so help can be
dispatched as quickly as possible. Because instrument readings are sent remotely, rescuers are
aware of the circumstances they will nd the victim in, making rescue operations faster and safer.
The Man Down Alarm can be switched on or o.
5.10 WIRELESS
When the instrument is equipped with wireless capability, it is set up through the wireless sub-menu.
6. Conguration Mode
In Cong (short for Conguration) Mode, you can modify instrument conguration settings.
6.1 ENTERING AND EXITING CONFIG MODE
1. From the main reading display, press and hold
EscEnt
OK and
EscEnt
OK
simultaneously until the instrument
asks for the password.
2. Input the 4-digit password, move the cursor to the checkmark, then press
EscEnt
OK to enter
Conguration Mode.
Note: The default password is 0000. You can change the password through a PC running WatchGas Suite software.
In Cong Mode, the screen on the right is be displayed.
The Calibration label is shown and its icon is highlighted.
• Use
EscEnt
OK or
EscEnt
OK
to scroll through the menu until the desired item is reached.
• Use
Esc
Ent
OK
to select the highlighted menu item.
To Exit Cong Mode:
• Press
Esc
Ent
OK
to go back.
• Repeat until the display shows the readout screen.
6.2 MAKING CHANGES IN CONFIG MODE
There are two types of menus in Cong mode:
1. Menus that ask for selection from a list.
2. Menus that ask for a numerical value to be entered.

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6.2.1 SELECTION FROM A LIST
For example, the Measurement sub-menu contains both a text-format list and a radio button list.
1. Use
EscEnt
OK and
EscEnt
OK
to scroll through the list. For high speed scrolling in long lists, press and hold
EscEnt
OK or
EscEnt
OK
.
2. Press
Esc
Ent
OK
to enter the selected submenu.
3. Press Esc
Ent
OK
to go back to the previous menu.
6.2.2 ENTERING NUMERICAL VALUES
For example, to enter a password:
1. Use
EscEnt
OK and
EscEnt
OK
to increase or decrease the selected number.
2. Use
Esc
Ent
OK
and
Esc
Ent
OK
to move to the next/previous number.
3. After entering values, use
Esc
Ent
OK
or
Esc
Ent
OK
to go to the checkmark to accept changes.
4. After entering values, use
Esc
Ent
OK
or Esc
Ent
OK
to go to the cross to cancel changes.
5. With checkmark or cross selected, press
EscEnt
OK to accept or cancel respectively, and move to the
next menu.
EscEnt
OK
EscEnt
OK
EscEnt
OK
EscEnt
OK
Esc
Ent
OK
Esc
Ent
OK
The example shown in this illustration is a ow chart of the NEO ppb.

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6.3 CONFIG MODE MENUS
This table summarizes the Cong Mode menus and sub-menus. Not all of these menus will be displayed
if the option is not set up using WatchGas Suite software.
Calibration Measurement Alarm Setting Datalog Monitor Setup Wireless
Zero Calibration Measurement Unit Alarm Limits Clear Datalog Date & Time Radio On/O
Span Calibration Measurement Gas Alarm Mode Interval Display Factory Reset
Set Cal. Gas Alarm Settings Pump Speed
Set Span Value Comfort Beep Set Pump Stall
Set Span 2 Value Man-Down Alarm Rolling Graph
3-point
Calibration
Real time data
Language
Self-Zeroing

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FLOW CHART FOR CONFIGURATION MODE
Rolling Graph
Factory Reset
3-point calibration

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7. Using Cong Mode Menus
7.1 CALIBRATION
Perform a calibration regularly. The instrument will hold its calibration, but
over time, detection circumstances change and instrument components get
contaminated, which can change the response of the instrument to detectable
gases.
Perform a bump test before each day’s use. This ensures that the instrument
is fully working, especially when the NEO is used to alert users to hazardous
concentrations of gas.
When feasible, perform calibration with the gas you are going to measure most often.
A calibration performed with isobutylene is a good alternative because it shows good response on PID
instruments, is inexpensive, stable and non-toxic.
A correction factor (CF) can be applied to make the NEO display the true concentration of the gas
being measured, if you are absolutely sure that only that gas is measured. You can select the CF from
the instrument’s gas library of over 200 compounds, or enter a CF manually. See Technical Note 2: PID
Correction Factors for more information.
7.1.1 CALIBRATION SET-UP
To perform a calibration, you need:
• A gas cylinder with calibration gas with an exactly determined concentration and a valid certicate
that is traceable to international standards.
• A source of clean air with 20.9 %vol of Oxygen:
• A gas cylinder with clean air in an exactly determined concentration and a valid certicate that is
traceable to international standards.
• Gas bag with clean air.
• Ambient air ltered through a charcoal tube (VOC Zeroing Tube).
• Outdoor ambient air usually contains a few ppb of VOC, and can only be used with instruments
with a resolution from 10 ppb and up.
• A ow regulator to control the gas ow from the cylinder.
• Tubing with Luer connectors to connect the gas source to the instrument.
To match the ow to the pump speed exactly, you can use a demand ow regulator. Alternatively:
• Fill a gas bag with calibration gas and connect the instrument with the gas bag when performing
span calibration.
• Use a ow regulator with a ow > 500 cc/min and let the excess ow escape through a T connector

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7.1.2 ZERO CALIBRATION
The zero calibration sets the baseline for the sensor. To perform a zero calibration:
1. Connect the instrument to a source of clean air.
2. Enter Cong Menu > Calibration Menu > Zero Calib Menu.
3. Conrm with
EscEnt
OK .
The instrument counts down to zero. When complete, the display shows “Zero Calibration Done!”. The
instrument proceeds to Span Calibration.
Note:
You can abort the calibration at any time by pressing Esc
Ent
OK
during countdown. The display shows“Zero aborted!”
and proceeds to Span Calibration.
7.1.3 SPAN CALIBRATION
Note: To ensure greater accuracy please preform a 3-point calibration.
The span calibration sets the second (and third, if 3-Point Cal is selected in Monitor Setup) calibration
point for the sensor. To perform a span calibration:
1. Check that 2-Point or 3-Point Calibration is set correctly (See 7.5.5 3-Point Calibration).
2. Check that the calibration gas is set correctly (See 7.1.4 Set Calibration Gas).
3. Check that the span values are set correctly (See 7.1.5 Set Span Value).
4. Connect the instrument to a source of calibration gas.
5. Enter Cong Menu > Calibration Menu > Span Calib Menu item.
6. Conrm with
EscEnt
OK .
The instrument counts down to zero. When complete, the display shows “Span 1 is Done! Reading = xx
ppm”. The reading should be very close to the actual concentration.
If 3-Point Calibration is enabled, proceed to perform Span 2 in the same manner.
Note:
You can abort the calibration at any time by pressing Esc
Ent
OK
during countdown. The display shows“Span aborted!”
and returns to the menu.
Span 1 is done!
Reading = 10.ppm

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NEO Model Span 1 Span 2
MP181 100 ppm 1000 ppm
MP182 100 ppm 5000 ppm
MP184 10 ppm 1000 ppm
MP185 10 ppm 1000 ppm
MP186 5 ppm (benzene) N/A
7.1.4 3POINT CALIBRATION
Normally, a 2-point calibration gives adequate linearity in PID
response. A 3-point calibration (Zero, Span 1 and Span 2) can be
enabled for more accuracy, particularly in the high concentration
range above about 500 ppm.
To set 3-point or 2-point calibration:
1. Press
EscEnt
OK or
EscEnt
OK
to select the desired option.
2. Press
Esc
Ent
OK
to continue.
3. Press Esc
Ent
OK
to save and exit
Below is the list of default 1st and 2nd Span points when using isobutylene for calibration.
These settings

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7.1.5 SET CALIBRATION GAS
Calibration to the gas normally measured by the instrument increases accuracy.
To set calibration gas:
1. Enter the Set Cal. Gas menu.
2. Select from Gas Library or Custom Gases.
3. Use
EscEnt
OK and
EscEnt
OK
to scroll through the list. Hold
EscEnt
OK or
EscEnt
OK
for high speed scrolling.
4. Press
Esc
Ent
OK
to select a gas.
5. Press
Esc
Ent
OK
to save and exit.
Warning
Calibrating the instrument to the gas you are measuring increases the accuracy of detection
results for that gas.
Note that calibrating the instrument to a single gas will not make the instrument respond to
that gas exclusively.
A PID instrument is a broad range detection device that shows calculated concentrations based
on ionisation of all detectable gases in the ambient air.
7.1.6 SET SPAN VALUE
Sets the concentration value that the instrument expects when performing a calibration. The span value
should exactly match the concentration of the gas you are using.
To set span value:
1. Enter the Set Span Value menu
The current span value is shown. The left most digit blinks.
2. Check and modify the Span Value as needed and accept changes.
The instrument returns to the Calibration menu.
If 3-Point Cal. Is selected, repeat this process for Span 2 Value.
The example shown in this illustration is a ow chart of the NEO ppb.

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7.2 MEASUREMENT
The sub-menus for Measurement are Measurement Unit and Measurement Gas.
7.2.1 MEASUREMENT UNIT
Choose the right measurement unit from the menu.
7.2.2 MEASUREMENT GAS
If you only expect one single gas, it is convenient to let the instrument apply the correction factor for that
gas automatically.
To set measurement gas:
1. Enter the Measurement Gas menu.
2. Select from Gas Library or Custom Gases.
3. Use
EscEnt
OK and
EscEnt
OK
to scroll through the list. Hold
EscEnt
OK or
EscEnt
OK
for high speed scrolling.
4. Press
Esc
Ent
OK
to select a gas.
5. Press Esc
Ent
OK
to save and exit.
Warning
Setting a measurement gas is convenient when measuring one single gas, because the value
shown in the display matches the detected concentration for that gas.
Setting a measurement gas does not make the instrument respond exclusively to that gas.
A PID instrument is a broad range detection device that shows a calculated concentration based
on ionisation of all detectable gases in the air.
Notes
• You can dene Custom Gases using WatchGas Suite.
• When setting a measurement gas from Custom Gases, the associated span value(s), correction factor and
default alarm limits are loaded into the instrument.
Unit Description
ppm Parts per million
ppb Parts per billion
mg/m3 Milligrams per cubic meter
µg/m3 Micrograms per cubic meter
µmol/mol Micromole per mol
10-6 Per million
The example shown in this illustration is a ow chart of the NEO ppb.

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7.3 ALARM SETTINGS
When using the instrument, the detected gas concentration is compared with
pre-set alarm limits. If the detected concentration exceeds any of the pre-set
limits, the alarms are activated.
You can:
• Change alarm limits.
• Enable or disable alarm latching. Alarms can be latched or can stop
automatically when detected concentrations fall below the alarm limits.
• Enable or disable buzzer and alarm LEDs individually.
• Enable or disable the Comfort Beep, a function that reminds you that the
instrument is functioning.
• Change various properties of the Man-Down Alarm.
Note
• Access to the alarm settings on the instrument can be restricted through WatchGas Suite software.
• The High alarm limit must be higher than the Low alarm limit.
7.3.1 CHANGE ALARM LIMITS
There are 4 dierent alarm limits, Low, High, TWA and STEL:
• Low and High alarms activate immediately when the detected concentration
exceeds their respective limit values.
• STEL alarm activates when the average detected concentration over the past
15 minutes exceeds its limit value.
• TWA alarm activates when the time weighted average of the detected
concentrations exceeds the time weighted average for a working day of 8
hours.
To change an alarm limit:
1. Enter the Alarm Settings Menu.
2. Enter the Alarm Limits sub-menu.
3. Scroll to the alarm you want to check and proceed with
Esc
Ent
OK
.
The display shows the current alarm limit. The left most digit blinks.
4. Check and modify the alarm limit as needed and accept changes.
5. The instrument returns to the Alarm Limits sub-menu.
6. When you have checked all alarm limits, press Esc
Ent
OK
to return to the Alarms
menu.
Warning
• Only change alarm settings if you are authorized to do so.
• Alarm limits should reect local laws and regulations.

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7.3.2 ALARM MODE
Choose if the alarm stops automatically when the detected concentration falls below the alarm limits
(Auto Reset). Latched means that the user must acknowledge an alarm with
Esc
Ent
OK
before it stops after the
detected concentration falls below the alarm limit.
1. Press
EscEnt
OK or
EscEnt
OK
to select the desired option.
2. Press
Esc
Ent
OK
to continue.
3. Press Esc
Ent
OK
to save and return to the alarm settings sub-menu.
7.3.3 ALARM SETTINGS
The buzzer and alarm LEDs can be programmed to be on or o individually or in
combination. Choose from:
• Both enabled
• LEDs only
• Buzzer only
• Both disabled
1. Press
EscEnt
OK or
EscEnt
OK
to select the desired option.
2. Press
Esc
Ent
OK
to continue.
3. Press Esc
Ent
OK
to save and return to the alarm settings sub-menu.
including date and time, pump parameters, display parameters and 3-point
calibration.