Bosean Electronic Technology BH-4M User manual

BH-4M
Portable Multi-gas Detector
User Manual
Bosean Electronic Technology Co.,Ltd
ISO9001-2015

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1. Brief Introduction
BH-4M portable gas detector (hereinafter referred to as the
detector) is an intelligent multi-parameter detector designed with
advanced integrated circuit technology, standard design
technology and proprietary digital-analog hybrid communication
technology.
The detector adopts natural diffusion or pump suction sampling
method for gas sampling, and the sensitive element adopts
high-quality gas sensor for gas detection. It has good sensitivity
and excellent repeatability. It is easy to use and maintain, which
greatly meets the safety detection of industrial sites. For the
requirements of high reliability of the equipment, the shell is made
of high-precision engineering plastics and non-slip rubber, with
high strength and good hand feeling. It can be widely used in
petroleum, chemical, environmental protection, smelting, refining,
biochemical medicine, agriculture, science and technology,
universities and other industries and fields.
The detector can detect 1-4 gas combinations according to
customer needs. Using integrated modules, it integrates
electrochemistry, catalysis, semiconductor, thermal conductivity,
optics and other detection principles to provide users with reliable,
accurate and safe gas detection solutions.
2.Instrument features
2.1 Features
* The new GUI design scheme is adopted, the interface display is
more comprehensive, and the operation is more user-friendly.
* Natural diffusion or pumping gas detection methods can be

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selected, and 1 to 4 gas types can be detected at the same time.
* Using miniature vacuum sampling pump, stable flow, long life
and low noise.
* It adopts a 2.0-inch high-definition color screen with a wide
viewing angle of 120 degrees.
* The three-button operation is simple and intuitive.
* Support a variety of extended functions to meet users' different
product applications.
2.2 Functions
*Sound, light, vibration and display four alarm modes.
*It supports switching between real-time gas concentration data
display and real-time curve display mode.
*It supports multi-point calibration, up to 5 points calibration.
*Multiple data storage methods, alarm storage, manual storage.
*Support Chinese and English switching, other languages can be
customized.
*Large-capacity (2500mAh) rechargeable lithium battery, which
can last longer.
*The USB interface adopts Type-C interface, and there is no fear
of plugging in front and back.
*Support TWA, STEL alarm function.

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3. Technical Data
Target Gas
Range
Low alarm
High alarm
Resolution
CH4
0～100%LEL
20%LEL
50%LEL
1%LEL
H2S
0～100ppm
10ppm
35ppm
1ppm
CO
0～1000ppm
50ppm
150ppm
1ppm
O2
0～30%vol
19.5%vol
23.5%vol
0.1%vol
Other gases needed, please contact supplier
Gas sampling method: Pump suction type, natural diffusion type
Response time: Pump suction type T90＜30s, natural
diffusion type T90＜60s
Detecting gas: Support 1~4 kinds of gas detection
Accuracy: ≤±5% F.S.
Indication: 2.0 inch color display, resolution 320*240
Alarm methods: Acousto-optic vibrating display quadruple
alarm, TWA/STEL alarm
Data communication: Support USB to connect to the upper
computer of the computer to view data
System language: Support Chinese and English switching;
other languages can be customized
Working environment: Temperature -10℃~50℃;
humidity<95%RH (no condensation)
Power Source: DC3.7V (Lithium battery capacity
2500mAh)
Charging way: Type-C charging interface, 5V/1A standard
charger
Standby time: ≥8h
Charging time: <5h
Gas Sensor Life: 2 years
Protection Grade: IP65
Weight: 372.5g(include pump)
Dimensions: Pump suction type 160*69*75mm; natural
diffusion type 150*69*55mm

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4. Structure
4.1 Structure function comparison table
4.1 Detector structure
It is mainly composed of shell, circuit board, battery, display screen,
sensor, charger and other components.
4.2 Sensor working principle
Electrochemical and catalytic combustion.
5. Function and operation
5.1 Power-on self-test and warm-up
When the detector is turned off, press and hold the middle button
for 3 seconds, the display of the detector displays the welcome

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interface (as shown in Figure 1), and then the instrument performs
the system initialization operation, and then performs the system
self-check and pre-check (sound, light, vibration, channel, etc.)
heat. When the preheating is completed, enter the main detection
interface of the detector (Figure 2).
Figure 1 Figure 2
5.2 Turn off
In the main menu interface of the detector, press and hold the
middle button for 3 seconds and then release the button to enter
the shutdown operation interface (Figure 3), click the left "Yes" to
confirm the shutdown, and click the right button "No" to cancel the
shutdown. Press and hold the middle button for 5 seconds to shut
down directly.
Figure 3

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5.3.1 Main interface function description
a. Display the current date and time.
b. Pump status indication. When the pump is normally turned on,
the icon rotates and the color changes to green; when the air
pump is normally closed, the icon does not rotate, and the color
changes to gray.
c. Buzzer status indication. When the gas concentration detection
is in the normal state, the icon is green; when the gas
concentration detection is in the low or high alarm state, after
pressing "Mute", the icon turns red.
d. Battery level indicator. The battery level is divided into six bars.
When there are two bars remaining, the icon turns yellow and the
screen prompts that the battery level is low. When there is one bar
of power remaining, the icon turns red and the screen prompts that
the battery power is low. When the power is exhausted, it will
automatically shut down.
5.3.2 Main interface display description
The detector shows the real-time
concentration of the relevant gas in the
environment as shown in Figure 4 under
the normal detection state.
Figure 4

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When the gas concentration detected by the detector is lower than
the set alarm value (Note: when the oxygen concentration is
higher than the low alarm value and lower than the high alarm
value), the detection status bar only displays the concentration
Value, no abnormal display.
When the gas concentration detected by the detector is higher
than the set low alarm value (Note: when the oxygen
concentration is lower than the set low alarm value), the detector is
in the low alarm state, the gas concentration value display color
changes to red, and the status bar displays "L", and the buzzer
beeps at 0.5s intervals, the alarm lights on both sides of the
screen flash synchronously, and the vibrator vibrates. If the screen
is in the off state, the screen lights up at the same time.
When the detector detects that the gas concentration is higher
than the set high alarm value, the detector is in the high alarm
state, the gas concentration value display color changes to red,
the detection status bar displays "H", and the buzzer emits "di" at
an interval of 0.25s. The beep sounds, the alarm lights on both
sides of the screen flash simultaneously, and the vibrator vibrates.
When the detector detects that the gas concentration is higher
than the sensor range, the detector is in the over-limit state, the
gas concentration value is displayed as red "HHHH", the detection
status bar displays "OV", and the buzzer interval 0.25s sends out a
"di" beep, the alarm lights on both sides of the screen flash
simultaneously, and the vibrator vibrates.

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When the detector detects the gas concentration for 8 hours, when
the calculated TWA value exceeds the set value, the gas
concentration value display color changes to red, and the
detection status bar displays "T".
When the detector detects the gas concentration for 15 minutes,
when the calculated STEL value exceeds the set value, the gas
concentration value display color changes to red, and the
detection status bar displays "S".
Note: When the alarm mute function is turned on, if a new alarm
state occurs, the buzzer will resume ringing.
When the gas concentration detected by the detector returns to
the lower limit alarm value, the gas concentration value color will
change to green, and the alarm signal will be automatically
released at the same time.
When multiple alarm states are detected in the same gas channel,
only the highest priority alarm will be issued.
The police priority is as follows:
Normal <Low alarm <High alarm<TWA <STEL <Out of limit
5.3.3 The main interface button function
description
Click the left button in the main interface to enter
the "Record" interface (Figure 5). Right-click to
select the gas to be viewed, and after clicking the
middle button, the gas alarm record operation can Figure 5

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be viewed on the interface (Figure 6). Single-click the right button
to turn the "next page" page, click the left button to turn the
"previous page" page, click the middle button to return to the
Figure 5 interface, and click the left button to return to the main
interface.
Right-click in the main interface to enter the "curve display"
interface (Figure 7). In this interface, you can view the real-time
detection curve of a certain gas channel within 10s. Click the left or
right button to switch the channel display, and click the middle
button to return to the main interface.
Click the middle button in the main interface to enter the "Main
Menu" interface (Figure 8). Click the left and right buttons to select
the function icon. Click the middle button to enter the
corresponding function interface.
Figure 6 Figure 7 Figure 8
5.4 Navigation bar function description
The navigation bar is displayed in three grids, corresponding to
three buttons respectively, and the corresponding functions can be
realized by operating the buttons.

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ICON
Usage
Return to the previous interface or status bar.
To confirm the data or function, enter the next
interface or status bar.
The start operation of the setting object.
The finish operation of the setting object.
Down shift function.
UP shift function.
Right shift function.
Perform calibration settings.
Occurs when alarming, and the buzzer alarm
sound is turned off after clicking.
Cancel the setting object.
After pressing, enter the view record operation
interface.
After pressing, enter the curve display operation
interface.

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5.5 Main menu interface description
As shown in Figure 8, click the left and right buttons to select the
function icon. Click the middle button to enter the corresponding
function interface.
ICON
Description
Usage
Channel setting
It’s used to set the parameters of
related channel gases and view the
setting information of each channel.
Alarm setting
Set alarm value to each channel.
Calibration
Perform calibration operations such as
calibration and zero adjustment on the
relevant channel gas.
System setting
Set time, language, backlight, air pump
and other system parameters.
Device
Information
Used to view the factory default
parameter information of the
instrument, etc.
Back
Back to main manu.
5.6.1 Channel information
In the main menu interface of the detector (Figure 8), select the
channel information icon to enter the channel information interface
(Figure 9). The left column of the figure is the gas option, and the
right is the channel information display area. Follow the navigation
bar prompts to set the operation (Figure 10, 11).

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Figure 9 Figure 10 Figure 11
5.6.2 Alarm setting
In the main menu interface of the detector, select the alarm setting
icon and click the middle button to enter the alarm setting interface
(Figure 12). The left side of the figure shows the gas options, and
the right side shows the alarm settings. Follow the instructions in
the navigation bar to set the operation.
There will be a corresponding prompt on the screen when the save
succeeds or fails (Figure 13).
Note: The low value must be less than the high value.
Figure 12 Figure 13 Figure 14
5.6.3 Calibration setting.
Warning: It is strictly forbidden for
non-professionals to perform this
calibration and other operations.
Figure 15

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Select the “calibration settings” icon in the main menu interface of
the detector, click the middle button to enter the password input
interface (Figure 14), follow the navigation bar prompts to set the
operation, and enter “1111” to enter the customer calibration
interface (Figure 15).
The customer calibration interface includes five functional options:
zero calibration, zero drift, concentration calibration, one-key zero
calibration, and factory reset (Figure 15).
Zero point calibration: Calibrate the gas zero point. The user
zero point interface (as shown in Figure 16) will continue to pass in
gas suitable for zero point calibration for a certain period of time.
After the value is stable, click the middle button to confirm and
save. There will be a corresponding prompt on the screen when
the save succeeds or fails (Figure 17).
Zero drift:After the sensor is used for a long time, the zero point is
offset, and the display is not zero in the clean air, and it can be
returned to zero through the zero point translation (Figure 18).
Concentration calibration: enter the corresponding
concentration gas, and perform concentration calibration on the
gas.
One-key zeroing: zeroing all the gases in use in the detector.
Factory reset: restore all configuration information of the sensor
module before leaving the factory.
Note: A series of operations such as zero point calibration have
been carried out before the detector leaves the factory, and the
user can directly use it normally. If the user does not operate
without the manufacturer's guidance, all the consequences shall
be borne by himself.

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Figure 16 Figure 17 Figure 18
5.6.4 System setting
Select the system setting in the main
menu of the detector, and click the
middle button to enter the system setting
interface (Figure 19). The setting options
include: time setting, backlight setting,
language setting, pump setting.
Figure 19
Time setting: Follow the navigation bar prompts to set the system
time (Figure 19).
Backlight setting: Set the brightness of the instrument's backlight,
there are three levels in total, and you can also set the backlight
delay time (Figure 20).
Language setting: Set the system display language (Figure 21).
Pump settings: set the pump switch (as shown in Figure 22), in the
main interface state, press the left and right keys at the same time,
the air pump can be directly turned on or off.
Figure 20 Figure 21 Figure 22

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5.6.5 Device information
Select the system information icon in the
main menu interface of the detector, and
click the middle button to enter the system
information view interface (Figure 23).
Click the middle button to return to the
previous menu.
Figure 23
6. Charging function description
When the interface prompts "The voltage is too low! Please
charge!" or the detector cannot be turned on normally due to
undervoltage, please charge in time; when the detector is off,
connect the charger plug to the charging jack of the detector, and
then Plug the charger's AC plug into the AC220V AC power supply,
the detector will automatically turn on and display the charging
status (Figure 24).After the charging is completed, the interface
will display "Charging Complete" (Figure 25). Turn on the detector
for normal use.
Figure 24 Figure 25 Figure 26
Undervoltage
When the battery is insufficient, the interface prompts "The voltage
is too low! Please charge!" every 1 minute (Figure 26).

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Undervoltage shutdown
When the battery power is lower than the
normal working voltage, the instrument
enters an automatic shutdown countdown,
and the instrument shuts down after the
countdown ends (Figure 27).
Figure 27
Note: Please try not to charge the tester when it is turned on, so as
not to affect the charging speed; please do not charge the tester at
the test site, so as to avoid unplugging and plugging the charger.
Sparks cause fire or explosion.
7. Possible fault and corresponding solution
Possible fault
Possible reason
Corresponding solution
The detector
can’t be turned
on
Too low battery
Please charge it in time.
The detector dies
Please contact the
manufacturer of dealer
Fault of electric
circuit
Please contact the
manufacturer of dealer
No response to
the gas
Warm up is not
finished
Wait till warm up is
finished
Fault of electric
circuit
Please contact the
manufacturer of dealer
Inaccurate
indication
Sensor is overdue
Please contact the
manufacturer or dealer to
replace the gas senor

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Uncalibrated for long
time
Please calibrate it in time
Fault indication
of time
Battery voltage is
used up
Please charge it and reset
time
Strong
electromagnetism
disturb
Please reset time
Zero calibration
is unavailable
Too much zero drift
of gas sensor
Please calibrate or
replace the gas sensor
Minus gas level
displayed
Gas sensor drift
Calibrate zero point
Sensor fault
indication
Sensor fault
Please contact the
manufacturer or dealer to
replace the gas senor
8. Accessories and others
220V charger and cable
1
Small screwdriver
1
Soft tube
1
User manual and Certificate of
conformity
1
Natural diffusion plastic board
1
9.Precautions for use
a. Prevent the instrument from falling from a height or subject to
strenuous exercise
b. In a high-concentration gas environment, the detector may cannot
be used normally.

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c. Please strictly follow the operation and use specifications in the
manual, otherwise it may cause inaccurate test results or damage the
instrument.
d. This product must not be stored or used in an environment
containing corrosive gases (such as high concentration of chlorine,
etc.), nor in other harsh environments, including excessively high or
low temperatures, high humidity, strong electromagnetic fields, etc.
Use or store this machine.
e. If there is dirt on the surface of the instrument after long-term use,
please wipe it gently with a clean soft cloth dipped in water. It is
forbidden to wipe the surface of the instrument with corrosive solvents
and hard objects, otherwise it may cause scratches or damage to the
instrument surface.
f. In order to ensure the detection accuracy of the instrument, the
instrument should be calibrated regularly, and the calibration period
should not exceed one year.
g. The battery pack cannot be disassembled or replaced in an
explosive gas environment, nor can the battery be charged; in an
explosive gas environment, peripheral plug-in instruments that have
not been certified for explosion-proof cannot be used, and sensors
cannot be replaced.
h. When the surface of the filter element at the gas sampling hole is
seriously polluted, please replace the filter element in time to ensure
the sensitivity and accuracy of the gas detection.
10. Sotre
The detector should be stored in a ventilated room with an ambient
temperature of -10 ℃~ 50 ℃and a relative humidity of not more than
85%, and the air must not contain harmful gases or impurities that
may corrode the detector.

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Henan Bosean Electronic Technology Co.,Ltd.
No.228,West 4th Ring,National High-Tech zone,Zhengzhou,China
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