WatchGas NEO User manual

USER MANUAL
Photo-ionization Detector
NEO
we watch gas where you can't

2
Photo-ionization Detector
NEO
CONTENTS
Read Before Operating 3
Description 3
Warnings 3
Proper Product Disposal at the end of life 4
User Interface 4
Display 5
1. Baery 6
1.1 Battery Charging 6
1.2 Low Voltage Warning 6
1.3 Clock Battery 6
1.4 Data Protection while Power is Off 7
2. Instrument Operation 7
3. Basic User Mode 7
3.1 Turning the NEO On and Off 7
3.2 User Mode Summary 8
3.3 User Mode Main Menu 9
3.4 Integrated Sampling Pump 9
3.5 Pump Status 9
3.6 External Water-Trap Filter 10
4. Alarms 10
4.1 Alarm Signals 10
4.2 Alarm Signal Summary 10
4.3 Preset Alarm Limits & Calibration 10
4.4 Testing the Alarms 11
4.5 Datalogging 11
4.6 Man Down 11
4.7 Wireless 11
5. Configuration Mode 11
5.1 Navigating Config Mode 11
5.2 Entering and Exiting Config Mode 12
5.3 Config Mode Menus 13
5.4 Calibration 15
5.5 Measurement 17
5.6 Alarm Settings 18
5.7 Datalog 20
5.8 Monitor (MNT) Setup 21
5.9 Wireless 24
6. Computer Interface Using WatchGas Suite 25
6.1 Connecting and Configuring 25
6.2 Datalog Retrieval 26
6.3 LDAR Sampling Record Retrieval 27
6.4 Real Time Data 28
7. Maintenance 30
7.1 Lamp Cleaning and Changing 30
7.2 Sensor Cleaning 31
7.3 Sampling Pump 31
6.1 Troubleshooting 32
8. Specifications 33
9. Limited Warranty 34

3
READ BEFORE OPERATING
This manual must be carefully read by all individuals who have or will have the responsibility of using,
maintaining, or servicing this product. The product will perform as designed only if it is used, maintained,
and serviced in accordance with the manufacturer’s instructions. The user should understand how to set
the correct parameters and interpret the obtained results.
DESCRIPTION
The NEO is one of the most advanced handheld VOC (Volatile Organic Compound) monitors available for
ppb (parts per billion) detection. The NEO offers several models from the most sensitive 1 ppb to a high
range up to 15000 ppm for different applications and user selections. Novel designs of the photo-ioniza-
tion 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 applicati-
on software.
CAUTION
To reduce the risk of electric shock, turn the power off before removing the instrument cover. Disconnect
the battery before removing sensor module for service. Never operate the instrument when the cover is
removed. Remove instrument cover and sensor module only in an area known to be non-hazardous.
SPECIAL NOTES
• When the instrument is taken out of the transport case and turned on for the first time, there may be
some residual organic or inorganic vapor trapped inside the detector chamber. The initial PID sensor
reading may indicate a few ppm. Enter an area known to be free of any organic vapor and turn on the
instrument. After running for several minutes, the residual vapor in the detector chamber will be cleared
and the reading should return to zero.
• The battery of the instrument discharges slowly even if it is turned off. If the instrument has not been
charged for 5 to 7 days, the battery voltage may be low. Therefore, it is good practice to fully charge
the instrument for at least 10 hours before the first use and to charge before each day’s use. It is also
recommended Refer to this User Guide’s section on battery charging for more information on battery
charging and replacement.
• Do not remove the filter when the instrument is on, otherwise, dust entry will reduce the accuracy of
measurement, shorten the life of the sensor, and possibly damage the sensor.
WARNINGS
STATIC HAZARD: Clean only with a damp cloth.
For safety reasons, this equipment must be operated and serviced by qualified personnel only. Read and
understand the instruction manual completely before operating or servicing.
• Use only WatchGas battery pack M011-3002-000. Substitution of components may impair intrinsic
safety. Recharge batteries only in non-hazardous locations.
• Do not mix old and new batteries or batteries from different manufacturers.
• For maximum safety, the accuracy of the instrument should be checked by exposing it to a known
concentration calibration gas before each day’s use.
• Do not use USB/PC communication in a hazardous location.

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Photo-ionization Detector
NEO
NOTE on FCC RULES
• This equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection
against harmful interference in a residential installation. This equipment generates, uses and can
radiate radio frequency energy and, if not installed and used in accordance with the instructions, may
cause harmful interference to radio communications. However, there is no guarantee that interference
will not occur in a particular installation. If this equipment does cause harmful interference to radio
or television reception, which can be determined by turning the equipment off and on, the user is
encouraged to try to correct the interference by one or more of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equipment into an outlet on a circuit different from that to which the receiver is
connected.
- Consult the dealer or an experienced radio/TV technician for help.
• To satisfy FCC/IC RF exposure requirements, a separation distance of 20 cm or more should be
maintained between the antenna of this device and persons during device operation. To ensure
compliance, operations at closer than this distance is not recommended.
PROPER PRODUCT DISPOSAL AT THE END
OF LIFE
The Waste Electrical and Electronic Equipment (WEEE) directive (2002/96/EC) is intended
to promote recycling of electrical and electronic equipment and their components at end
of life. This symbol (crossed-out wheeled bin) indicates separate collection of waste
electrical and electronic equipment in the EU countries. This product may contain one or
more Nickel-metal hydride (NiMH), Lithium-ion, or Alkaline batteries. Specific battery in-
formation is given in this user guide. Batteries must be recycled or disposed of properly.
At the end of its life, this product must undergo separate collection and recycling from
general or household waste. Please use the return and collection system available in your
country for the disposal of this product.
USER INTERFACE
INLET FILTER
SENSOR CAP
ALARM LED’S
LCD DISPLAY
GAS OUTLET
BUZZER
RIGHT KEY
MOVE CURSOR
DOWN/MODE KEY
ON/OFF
UP KEY
LEFT KEY
RIGHT KEY
UP KEY
DOWN /
MODE KEY
LEFT KEY
MOVE CURSOR
Esc
Ent
OK
Esc
Ent
OK
EscEnt
OK
EscEnt
OK

5
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:
BACKLIGHT
The LCD is equipped with an LED backlight that can be turned on manually or set to come
on automatically to assist in reading the display under low light conditions.
MAN DOWN
STATUS
PUMP STATUS
CALIBRATION//
BUMP DUE
BATTERY STATUS
DATALOG STATUS
READING AND MEASU
RING UNIT
LAMP STATUS
TIME
GAS NAME AND
CORRECTION FACTOR
TEMPERATURE
ITEM DESCRIPTION
Gas information Shows the measurement gas and its correction factor
Reading Concentration of gas measured by the instrument
Calibration Due Cylinder icon appears when calibration is due
Pump Status Indicates whether the pump is working or blocked
Man-Down Status Icon appears when Man-Down alarm is enabled
Lamp Status Lamp icon is shining when on and crossed out when off
Datalog On Verifies that datalogging is on
Battery Status Indicates battery capacity in 3 bars
Time Indicates current time
Temperature Indicates current temperature inside the instrument
LCD Display

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Photo-ionization Detector
NEO
. BATTERY
1.1 BATTERY CHARGING
Always fully charge the battery before using the instrument. The screen will display a
battery icon from empty (no bars) to fully charged (3 bars).
Follow this procedure to charge the instrument:
1. Plug the Micro-USB into the charging port at the bottom of the instrument.
2. Plug the USB connector* into either a) a personal computer, or b) into the AC/DC
adapter and plug the AC/DC adapter into the wall outlet.
The instrument begins charging automatically. The charging LED turns red
to indicate charging. During charging, the 3 bars in the battery icon on the
instrument’s display are animated. When the battery is fully charged, the
LED turns green, the icon is no longer animated and shows a full battery,
and the message ‘Fully Charged’ is displayed.
*NOTE: Any locally-obtained USB A to Micro B USB cable will work for charging, but
will not work for communication with WatchGas Suite configuration and data transfer
software. The WatchGas USB cable P/N M-011-3003-000 is required for a PC to
recognize the instrument and communicate with WatchGas Suite.
1.2 LOW VOLTAGE WARNING
When the battery’s charge falls below a preset voltage, the instrument
warns you by beeping once and flashing once every minute, and the
“empty battery” icon blinks on and off once per second. Turn off the
instrument within 10 minutes and either recharge the battery, or replace
the battery with a fresh one with a full charge.
1.3 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. This backup battery should last approximately
five years, and must be replaced by an authorized WatchGas service technician. It is not
user-replaceable.
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’s rechargeable lithium battery part number:
M011-3002-000.

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1.4 DATA PROTECTION WHILE POWER IS OFF
When the instrument is turned off, all the current real-time data including last measured
values are erased. However, the logged data are preserved in non-volatile memory, so
that even if the battery is disconnected, the logged data will not be lost.
. INSTRUMENT OPERATION
The WatchGas NEO gives real-time measurements and activates alarm signals whenever
the readings exceeds preset 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 verified before the first use.
After the instrument is fully charged and calibrated, it is ready for immediate operation.
The instrument works in different operation modes defined by the product model and
factory setting. When the unit is turned on, it enters User Mode, where basic users can
only see and use a limited set of functions. In Configuration Mode, which is password
protected, advanced users can adjust various settings. In some cases, Configuration Mode
is not accessible on the instrument display and the WatchGas Suite software must be
used to change settings.
. BASIC USER MODE
3.1 TURNING THE NEO ON AND OFF
Turning On. Press and hold the Mode key
EscEnt
OK
until the display, beep buzzer & LEDs turn
on, and then release.
If the WatchGas logo does not appear first, there is likely a problem and a distributor or
WatchGas Technical Support should be contacted. The instrument then performs self-
tests after the screen displays the firmware version and serial number.

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Photo-ionization Detector
NEO
Self-tests include:
After self-tests, the instrument will show sensor
and instrument configuration information in
sequence. Once the numerical reading screen with icons is displayed, the instrument is
fully functional and ready for use.
Turning Off: Press and hold the Mode key
EscEnt
OK
for 3 seconds, and continue to hold for a
5-second countdown until “Unit off...” is displayed.
3.2 USER MODE SUMMARY
After being turned on, the NEO will be running in either of two Basic User Operating
Modes, which can be selected in the Monitor Set-Up sub-menu (see Configuration Mode
section):
3.2.1 HYGIENE MODE
This is the standard mode that displays real-time concentration readings, compares them
to alarm limits, performs TWA and STEL calculations and logs the data. It also show
varied auxiliary information and enables features such as rolling graph display and real-
time data transfer to a PC.
3.2.2 SEARCH MODE LDAR SAMPLING
This mode records up to 9999 individual sample readings during a window of time initiated
by the user. It is ideal for Leak Detection and Repair (LDAR) sampling. For detailed LDAR
sampling procedures, see the Configuration Mode section Monitor Set-Up sub-menu
(Operating Modes).

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3.3 USER MODE MAIN MENU
Press the Up key
EscEnt
OK or Mode key
EscEnt
OK
to cycle through the main menu screens. If no
action us taken on any screen for 60 seconds, the display will return to the main menu
automatically.
3.4 INTEGRATED SAMPLING PUMP
The instrument includes an integrated, diaphragm-type sampling pump, providing flow
rates of 330 to 450 cc/min. adjustable in three speed settings. When used with a 25
mm diameter 0.45 m filters the flow rate is about 250 to 360 cc/min. at low and high
settings. Flow will decrease if the filter accumulates particulate matter, or if a filter is
not used and particles get caught in the pump diaphragm. Connecting Teflon tubing with
1/8” inside diameter to the gas inlet port, this pump can pull air samples from 200’ (61 m)
away horizontally, or 90’ (27.5 m) vertically, at about 3’ (0.9 m) per second flow rate. Note
that at 200’ the PID response will be delayed by about 1 minute, the time required for the
gas sample to reach the instrument.
IMPORTANT!
During operation, make sure the probe inlet and the gas outlet are free of obstructions.
Obstructions can cause premature wear on the pump, false readings, or pump stalling.
3.5 PUMP STATUS
During normal operation, the pump icon alternately shows inflow and
outflow. If there is a pump failure or obstruction, the alarm sounds
and the pump stall icon blinks on and off. If this occurs, clear the
obstruction and press the Right key to restart the pump.
SEARCH HYGIENE
WATCHGAS BLE
Flow chart for basic User Mode main menu

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Photo-ionization Detector
NEO
3.6 EXTERNAL WATERTRAP FILTER
The external filter is made of a PTFE (Teflon ®) or PVDF membrane with 0.45 micron pore
size to prevent dust or other particles from being sucked into the sensor manifold, which
could damage the instrument. It prolongs the operating life of the sensor and pump. To
install the external filter, simply screw it in to the instrument’s inlet probe using the Luer
connection.
. ALARMS
4.1 ALARM SIGNALS
During each measurement period, the gas concentration is compared with the programmed
alarm limits (gas concentration alarm limit settings). If the concentration exceeds any of
the preset limits, the buzzer and red flashing LED are activated immediately to warn of
the alarm condition.
In addition, the instrument alarms under various other fault conditions, including low
battery voltage, UV lamp failure, pump stall gas concentration over-range, etc, as shown
below.
4.2 ALARM SIGNAL SUMMARY
MESSAGE CONDITION ALARM SIGNAL
HIGH Gas exceeds ‘High Alarm’ limit 3 beeps/flashes per second
OVR Gas exceeds measurement range 3 beeps/flashes per second
MAX Gas exceeds electronics’
maximum range
3 beeps/flashes per second
LOW Gas exceeds ‘Low Alarm’ limit 2 beeps/flashes per second
TWA Gas exceeds ‘TWA’ limit 1 Beep/flash per second
STEL Gas exceeds ‘STEL’ limit 1 Beep/flash per second
Pump icon
flashes
Pump failure 3 beeps/flashes per second
Lamp PID lamp failure 3 beeps/flashes per second
plus ‘Lamp’ message
Battery icon
flashes
Low battery 1 flash, 1 beep per minute
plus battery icon flashes
CAL Calibration failed, or is overdue 1 beep/flash per second
NEG Gas reading measures less than
number stored in calibration
1 beep/flash per second
4.3 PRESET ALARM LIMITS & CALIBRATION
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:
Alarm limits and calibration parameters can be adjusted in Configuration Mode as desired
for particular testing purposes and applications.
CAL GAS CAL SPAN UNIT LOW HIGH TWA STEL
Isobutylene 10 ppm 50 100 10 25

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4.4 TESTING THE ALARMS
The alarm can be tested whenever the main (Reading) display is shown. Press the Right
key, and the audible and visible alarms are tested.
4.5 DATALOGGING
During datalogging, the instrument displays a disk icon to indicate that datalogging is
enabled. The default status is to have datalogging on, at 60-second intervals, which
allows up to one year of data storage.
The instrument stores the measured gas concentration at the end of every sample interval
(when datalogging is enabled). In addition, the following information is stored: user ID,
site ID, serial number, last calibration date, and alarm limits. All data are retained (even
after the unit is turned off) in non-volatile memory so that it can be down- loaded at a
later time to a PC. Stored data are organized into ‘events’, with a new event created each
time the instrument is turned on, or a configuration parameter is changed, or datalogging
is interrupted.
After an event is recorded, the unit records a shorter form of the data. When transferred
to a PC running WatchGas Suite, these data are arranged with a sample number, time,
date, gas concentration.
4.6 MAN DOWN
Settings are available for On/Off depending on the user’s requirement.
The Man Down Alarm is a critical and potentially lifesaving safety feature of the NEO.
Its function is based on the premise that if the instrument is motionless when it is not
supposed to be, its user may be in distress. If that is the case, the NEO not only goes
into alarm locally on the instrument, but also remotely, over a wireless network, to notify
people in the vicinity, as well as remote safety officers at a command center, that a
person is down, so that help can be dispatched quickly.
Note: Remote notification requires wireless connection to a network.
4.7 WIRELESS
When NEO is equipped with wireless capability, it is set up through the wireless sub-
menu.
. CONFIGURATION MODE
The Config Mode is used to modify the instrument configuration settings.
5.1 NAVIGATING CONFIG MODE
There are two types of menus in Config mode: 1) those that ask for selection from a list
and 2) those that ask for a numerical value to be entered.

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Photo-ionization Detector
NEO
5.1.1 SELECTION FROM A LIST
For example, the Measurement sub-menu contains both a text-format list and a radial-
button list.
• Press the Up key
EscEnt
OK or Mode key
EscEnt
OK
to scroll through the list.
• Press the Right key
Esc
Ent
OK
to select the menu item.
• Press the Left key
Esc
Ent
OK
to save and exit.
5.1.2 ENTERING NUMERICAL VALUES
For example, to enter a numerical password:
• Increase or decrease the number from 0 through 9
by pressing the Up key
EscEnt
OK or Mode key
EscEnt
OK
.
• Press the Left key
Esc
Ent
OK
or Right key
Esc
Ent
OK
to move the cursor.
• After entering the desired numbers, press the Left key
Esc
Ent
OK
or Right key
Esc
Ent
OK
to move the
cursor to the ‘ ’ mark, and then press the Up key
EscEnt
OK to accept and move to the
next menu.
5.2 ENTERING AND EXITING CONFIG MODE
From the main reading display, press and hold the Up key
EscEnt
OK and Mode key
EscEnt
OK
simultaneously until the Password screen is shown. Input the 4-digit
password, move the cursor to ‘ ’, then press the Up key
EscEnt
OK to enter
Configuration Mode.
Note: The default password is 0000. The password can only be
changed by connecting the instrument to a PC running
WatchGas Suite software.
EscEnt
OK
EscEnt
OK
EscEnt
OK
EscEnt
OK
Esc
Ent
OK
Esc
Ent
OK

13
Upon successfully entering Config Mode, the screen on the
right will be displayed. The Calibration label is shown and its
icon is highlighted. Use the Up key
EscEnt
OK or Mode key
EscEnt
OK
to
scroll through the menu until the desired item is reached, and
use the Right key to select it.
To Exit Config Mode and return to normal operation, press the
Left key repeatedly from any of the Config Menu displays.
5.3 CONFIG MODE MENUS
This table summarizes the Config 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 Seing Datalog Monitor Setup Wireless Exit
Zero Calib Meas. Unit Alarm Limits Clear Datalog Data & Time Radio On/Off
Span Calib Meas. 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 Cal. Real Time Data
Language
Self-Zeroing
Temp. Unit
Operation
Mode
Site ID
User ID

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Photo-ionization Detector
NEO
Flow chart for Configuration Mode

15
5.4 CALIBRATION
5.4.1 CALIBRATION OVERVIEW
Although the instrument will typically hold an approximate
calibration for several weeks, when used for worker health and
safety it should be calibrated or bump tested before each day’s
use. The interval between span calibrations can be extended based
on the user’s experience for how long the calibration holds under
their operating conditions. For best accuracy the calibration gas
chosen is the same as the gas to be measured. However, this
is often inconvenient, and isobutylene has become the standard surrogate calibration
gas because it has good response and is inexpensive, stable, and non-toxic. A correction
factor (CF) can then be applied to make the NEO display in true concentration units of
the gas being measured. This CF is selected from the instrument’s gas library of over 200
compounds, or entered manually.
5.4.2 CALIBRATION SETUP
Span gas from a cylinder is conveniently supplied to the instrument using a regulator with
fixed flow rate of about 0.5L/min (500 cc per min.) to match or slightly exceed the flow
rate of the instrument pump. Alternatively, the span gas can first be filled into a gas bag
(e.g., Tedlar® bag) or delivered through a demand-flow regulator to match the pump flow
precisely. Another alternative is to use a regulator with >500 cc/min flow but allow the
excess flow to escape through a T connector or an open tube.
5.4.3 ZERO CALIBRATION
This procedure determines the zero point of the sensor calibration curve. Connect the
instrument to a clean air source free of VOCs such as from a cylinder, gas bag, or ambient
air filtered through a charcoal tube (VOC Zeroing Tube). Most outdoor air is sufficiently
free of contaminants that it can be used for zero calibration except for measurements in
the low ppb range. The air source should have an oxygen concentration of 20.9% (or the
same as in the gas to be measured) because oxygen levels have some effect on the PID
response.
Select ‘Zero Calib’ by pressing the Right key to enter the submenu. The message ‘ Please
Apply Zero Gas’ is displayed. Start the zero calibration by pressing the Up key, and a 30-
second countdown begins.
Note: To abort the zeroing and proceed to Span calibration, press the Left key at any time
during the process. A confirmation message ‘Zero aborted!’ will appear, followed by the
Span calibration menu.
When complete, this message “Zero Calibration Done!” is shown, and the display
automatically moves to the Span Calibration menu.

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Photo-ionization Detector
NEO
5.4.5 SPAN CALIBRATION
This procedure determines the second (and third, if 3-Point Cal is selected in Monitor
Setup) point(s) of the sensor calibration curve. One or two cylinders of standard reference
gas (span gas) fitted with a 500 cc/min flow-limiting regulator or a flow-matching regulator
is the simplest way to perform this procedure. The span gas concentration should be
chosen to be near the highest concentration of actual measurements expected. It is
also preferred to use the same balance gas (e.g., air or nitrogen) as occurs in the actual
measurements.
To perform a Span calibration, connect the calibration adapter to the inlet port of the
instrument, and connect the tubing to the regulator or gas bag. Select ‘Span Calib’ by
pressing the Right key to enter the submenu. The message ‘Please Apply Gas’ is displayed.
Start the gas supply and by press the Up key to begin a 30-second span calibration
countdown. The calibration will also start automatically without pressing the Up key if a
high enough gas concentration is detected.
Note: To abort the Span calibration, press the Left key at any time during the process.
The confirmation message ‘Span is aborted!’ appears followed by the next menu item.
When Span 1 calibration is complete, a message similar
to this is displayed (the value is an example only):
5.4.6 3POINT CALIBRATION
If ‘3-Point Cal.’ is enabled (see Monitor Setup), proceed to perform Span 2 in the same
manner as for Span 1.
3-Point calibration should be used whenever enhanced accuracy is required. It is especially
recommended for measurements above about 500 ppm, where PID response is not quite
as linear.
5.4.7 SET CALIBRATION GAS
In the Set Cal. Gas menu, select the calibration gas from either the WatchGas Gas Library
or the user’s Custom Gases list. Custom Gas names and parameters can only be set up
through the WatchGas Suite software.
Span 1 is done!
Reading = 10.ppm

17
Press the Right key to select Gas Library, or Custom Gases. Press the Up key or Mode key
to scroll through the gas list. For high-speed scrolling, press and hold the Up key until
the desired gas name is reached. Press the Right key to select the gas and the Left key
to save and exit.
5.4.8 SET SPAN VALUE
Span value settings (including Span 2) should match the concentration(s) of standard gas.
Check to ensure that the unit of concentration (e.g., ppm or mg/m3) on the gas cylinder
agrees with the instrument setting.
5.4.9 3POINT CALIBRATION
Normally a 2-point calibration gives adequate linearity in
PID response, but 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 where
response is less linear. Use the Right key to enter 3-Point Cal,
then Up or Mode to scroll to On or Off, Right to select, and Left
to save and exit.
Below is the list of default 1st and 2nd Span points when using isobutylene for calibration.
These settings can be changed in the Calibration menu.
NEO MODEL SPAN 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
5.5 MEASUREMENT
The sub-menus for Measurement are Measurement Unit and Measurement Gas.
5.5.1 MEASUREMENT UNIT
Standard available measurement units include:

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Photo-ionization Detector
NEO
Unit Description
ppm Parts per million
ppb Parts per billion
mg/m3 Milligrams per cubic meter
g/m3 Micrograms per cubic
meter
mol/
mol
Micromole per mol
10-6 Per million
5.5.2 MEASUREMENT GAS
Measurement gases are organized in two lists:
• Gas Library is a pre-set list that contains about 700 chemicals detectable by PID.
• Custom Gases are user-defined, using WatchGas Suite to set up all gas parameters,
including the name, span value(s), correction factor(s), and default alarm limits.
Press the Right key
Esc
Ent
OK
to select Gas Library, or Custom Gases. Press the Up key
EscEnt
OK or
Mode key
EscEnt
OK
to scroll through the gas list. For high-speed scrolling, press and hold the
Up key
EscEnt
OK until the desired gas name is reached. Press the Right key
Esc
Ent
OK
to select the
gas and the Left key
Esc
Ent
OK
to save and exit.
5.6 ALARM SETTINGS
During each measurement period, the gas concentration is
compared with the programmed alarm limits (Low, High, TWA
and STEL). If the concentration exceeds any of the preset
limits, the loud buzzer and red flashing LED are activated
immediately to warn of the alarm condition. Press the
Right key
Esc
Ent
OK
to enter the Alarm Setting menu.
5.6.1 ALARM LIMITS
In this menu, the High, Low, STEL,
and the TWA alarm limits can
be changed. Press the

19
Right key
Esc
Ent
OK
to enter the
Alarm Limits menu.
5.6.2 HIGH ALARM
The default High Alarm limit is set by the instrument to
match the value for the current measurement gas. To
change the High Alarm limit press the Up or Mode key
to increase or decrease each digit’s value, and the Right
or Left key to move the cursor. Move the cursor to ‘ ’ after the setting is complete, and
press Up to save and exit.
5.6.3 LOW, STEL AND TWA ALARMS
Set the Low, STEL and TWA Alarm limits in the same manner as described above for the
High Alarm limit.
Note: All default alarm limits depend on the measurement gas and are expressed in ppm.
5.6.4 ALARM MODE
There are two selectable alarm modes:
LATCHED
When the alarm is triggered, it stays on even when the concentration falls back below
the alarm limit. The alarm must be stopped manually by pressing the Right key
Esc
Ent
OK
. The
latched setting only controls High, Low, STEL, and TWA alarms.
AUTOMATIC RESET
When the alarm condition is no longer present, the alarm stops automatically.
Press the Up
EscEnt
OK or Mode key
EscEnt
OK
to step from one alarm mode to the other. Press
Right to select an alarm mode followed by Left to save and exit.
5.6.5 ALARM SETTINGS
The buzzer and light alarms can be programmed to be on or off individually or in
combination. The choices are:
• Both on
• Light only
• Buzzer only
• Both off
Press the Up
EscEnt
OK or Mode key
EscEnt
OK
to step from one option to the next. Then press
Right to make a selection followed by Left to save and exit.

20
Photo-ionization Detector
NEO
5.6.6 COMFORT BEEP
With the Comfort Beep enabled, the buzzer beeps once each minute to indicate that all
is OK and the instrument is running normally.
Press the Up or Mode key to step from one option to the next. Then press Right to make
a selection followed by Left to save and exit.
5.6.7 MANDOWN ALARM
The Man-Down alarm notifies nearby personnel if the instrument remains motionless for
about 30 seconds when it should be moving, indicating a possible worker in distress. If
the wireless option is enabled, alarm notification is also sent to a remote location. During
the Warning Time the alarm beeps 2x per second and asks the user ‘Are You OK?’.
If so, the user can acknowledge and stop the alarm by pressing the Left Key, or simply
tilting the instrument briefly. If the Warning Time expires without acknowledgment, the
full Man-Down Alarm of 3x beeps per second begins.
MANMANDOWN ALARM OFF/ON
Press Right to make a selection followed by Left to save and exit.
SENSITIVITY
This sensitivity of motion sensor can be set to Low, Medium
or High. Low sensitivity means fewer alarms and High sensitivity
means easier detection of stopped motion and more chance of an
alarm. Use Up or Mode to move up or down the list, Right to select,
and Left to save and exit.
WARNING TIME
The Warning Time is the amount of time the Man-Down alarm
stays on after it is triggered. The default time is 30s.
5.7 DATALOG
The instrument automatically stores the concentration readings
at regular time intervals (this function cannot be turned off).
In the datalog sub-menu, a user can adjust the interval or
clear all data. Press Right to enter the Datalog menu.
5.7.1 CLEAR DATALOG
This erases all the data stored in the datalog.