Four Gas Detector with High Accuracy (Dust-Proof, Data Store)

This portable ‘Four Gas Detector with High Accuracy (Dust-Proof, Data Store)’ detects O2, LEL, CO, H2S and provides safety for staff working under the hazardous environment



GAOTek ‘Four Gas Detector with High Accuracy (Dust-Proof, Data Store)’ is a portable multi-gas detector. It continuously monitors four types of gases: O2, LEL (combustible gas), CO, H2S. It also provides four kinds of sensor type customization. Users can match any of the four according to their needs to select the sensor. Each gas concentration degree will be displayed on the TFT color liquid crystal. The instrument provides a user-settable low concentration of self/high alarm and STEL/TWA alarms. The instrument uses a new generation of imported toxic gas sensors, PID photo-ionization sensors, catalytic combustion of combustible gas sensor and independent research and development of infrared gas sensors. It is safe and reliable providing security for the staff from poisonous gases in dangerous environment.


Key features

  • Small size, light weight and easy to carry
  • High accuracy, short response time, wide measurement range
  • Large screen color LCD graphic display
  • USEI rechargeable lithium battery with long life for fast and easy charging
  • Built-in large capacity memory stores large amounts of measurement data
  • Powerful sound and light alarm with vibration alarm variety of alarm mode
  • Water proof, dust proof, explosion proof and rugged enclosure drop resistance protection
  • Supports USB and the upper machine communications
  • Ppm and mg/m³ unit switch
  • Warning lights flashing makes it convenient to work in the dark
  • Password to restrict and protect the configuration menu changes



Technical Specifications

Product type Portable multi-gas detector
Sensor type Toxic electrochemical, catalytic combustion of combustible gas, PID photo-ionization, ad hoc research and development of infrared gas sensor
Battery Built-in rechargeable lithium battery (3.7 V, 3000 mA)
Operating hours Fully charged for longer than 20 hours
Charging time Less than 4 hours
Display TFT colorful screen
Alarm Audible alarm, a red LED light alarm, vibration alarm
Keyboard 4 keys
Sampling way Diffused type
History record 30-second intervals can store more than one month record
Alarm record 200 alarm recording, loop record
Calibrate 2-point calibration, you can set the nominal concentration
Operating Temperature -4 °F ~ 131 °F (-20 ℃ ~ 55 ℃)
Working Humidity 0-95 % RH (non-condensing)
Size 5.11 in × 3.14 in × 1.65 in (130 mm × 80 mm × 42 mm)
Weight 0.66 lbs (300 g)
Warranty 1 year



Additional Information

Ordering Information

Product Selection

Model Number Product Type Electro chemical sensor Combustion catalytic sensor PID sensor Infrared Sensor
GT00Z200XB PRO 3 kinds Yes No No
GT00Z200XB-A PRO-EC 4 kinds No No No
GT00Z200XB-B PRO-PID 2 or 3 kinds Optional Yes No
GT00Z200XB-C PRO IR 2 or 3 kinds Optional No 1 or 2 kinds
GT00Z200XB-D PRO PID+IR 1 or 2 kinds Optional Yes 1 or 2 kinds

Electro-chemical sensor order and parameter table:

Gas Type Range Low alarm value High alarm value TWA value STEL value Unit
LEL 0-100 %LEL 25 50 %LEL
CO 0-500 PPM 35 200 35 200 PPM
H2S 0-50 PPM 10 15 10 15 PPM
NH3 0-100 PPM 25 50 25 35 PPM
SO2 0-20 PPM 2 5 2 5 PPM
NO2 0-20 PPM 3 5 5 5 PPM
CL2 0-20 ppm 0.5 1.0 0.5 1.0 ppm
Br2 0-20 ppm 0.1 0.5 0.1 0.5 ppm
CLO2 0-20 ppm 0.1 0.2 0.1 0.3 ppm
PH3 0-5 ppm 0.3 1.0 0.3 1.0 ppm
HCL 0-20 ppm 2.0 5.0 2.0 5.0 ppm
HBr 0-20 ppm 2.0 5.0 2.0 5.0 ppm
HCN 0-100 ppm 4.7 10.0 4.7 10.0 ppm
H202 0-100 ppm 1.0 3.0 1.0 3.0 ppm
ETO 0-20 ppm 1.0 5.0 2.0 5.0 ppm
CH2O 0-5 ppm 0.1 0.3 0.1 0.3 ppm
COCL2 0-1 ppm 0.1 0.3 0.1 0.3 ppm
NO 0-100 ppm 25 50 25 50 ppm
SiH4 0-50 ppm 2.0 5.0 2.0 5.0 ppm
O3 0-5 ppm 0.1 0.3 0.1 0.3 ppm
H2 0-1000 ppm 200 500 200 500 ppm
O2 0-25 %vol 19.5 23.9 %
C2H4 0-200 ppm 20 50 20 50 ppm

Sensor order and Parameter table:

Order numb-er Label Color Range Resolu-tion(ppb) Respo-nse Time(sec) Low alarm value High alarm Value
PID-10000 Green 10000 100 < 3 1000 4000
PID-2000 purple 200 500 < 3 200 600
PID-200 red 200 50 < 3 20 60
PID-20 yellow 20 5 < 3 2 8
PID-2 blue 2 0.5 < 3 0.5 ppm 1.0 ppm 

IR Sensor order and parameter table:

Order number Gas Type Series Model Number Range Resolution
IRCH4-5 CH4 A CH4-5/A-5 0-5 % VOL 0.01 % VOL
IRCH4-100 CH4-5/A-100 0-100 % VOL 0.1 % VOL
IRCO2-1 CO2 B CO2/B-1 0-1 % VOL 0.001 % VOL
IRCO2-10 CO2/B-10 0-10 % VOL 0.01 % VOL
IRCO2-20 CO2/B-20 0-20 % VOL 0.01 % VOL
IRCO2-100 CO2/B-100 0-100 % VOL 0.1 % VOL
IRHC-5 HC C HC/C-5 0-5 % VOL 0.01 % VOL
IRHC-100 HC/C-100 0-100 % VOL 0.1 % VOL

IR Sensor order and parameter table:

1. Appearance of the instrument

The instrument includes a display screen, four highlighted alarm LED lights, a charging indicator light, buzzer and four action buttons. The display displays a variety of test data and instrument status information. The charge indicator indicates the charge state. USB interface can be used to charge as well as to connect with the host computer. Built-in vibration motor which makes the alarm vibrate, allows users to more easily use in noisy environments.

2. Parts of the instrument assembly drawing

①: screw stopper ②: Screw ③: the lower lid ④: Sensor Board

⑤: sensor plate ⑥: Sensor ⑦: cover ⑧: Calibration cover

⑨: Calibration cover fixing screw

3. Charge

The instrument should be charged before using. It can be charged via the USB interface. Please pull out the USB soft plug before charging, connect USB charger and the instrument automatically starts charging. During charging, the indicator light is red and it turns green after it is complete.

When the battery voltage is less than the operating voltage, the instrument will automatically shut down. In this case the instrument cannot boot and you must connect the charger before use.

Unplug the USB rubber plug at the bottom of the instrument

When the battery is less than 20 % and less than 10 %, the buzzer starts sounding and the power indicator on the LCD screen gives out a red low-battery warning symbol. When the battery is running out, the instrument automatically shuts down and powers off in 3 seconds.

4. Battery use

Battery performance is affected by many factors, including sensor type, instruments’ temperature and the chosen or used functions or settings.

In order to achieve optimal battery performance, observe the following rules:

  1. A new battery or unused battery takes a long time to charge
  2. While charging, keep the battery at or near room temperature
  3. High temperature, exposure and other factors will reduce battery life. Try to avoid this type of environment.
  4. After long-term use, the battery will gradually wear out and needs to be changed. You need to buy original batteries or batteries approved by the Company as inferior parts can damage equipment and cause danger!

5. Instrument startup and shutdown

Start Up

Press and hold the power button for more than three seconds, the instrument automatically turns on. Boot the speaker alarm. The instrument self-tests for 90 s and shows the concentration detection interface.

If the following conditions occur, press the power button for 3 seconds to restart the device.

  • The buzzer does not sound
  • Vibration alarm does not work
  • LED does not light Indicating an error


In addition to the instruments’ preheat mode, regardless of the instrument being in any other mode, hold down the switch button for 5 seconds, release the button, the screen is off, the instrument is turned off.

6. Operation of the instrument

6.1 Overview of Operation

During normal use, there are two modes of operation: normal mode, program mode. Conventional mode is the mode to enter after the start of the instrument, also called measurement mode. After booting, the instrument automatically enters the normal mode to measure gas concentration, displays the current measured gas concentration.

Programming mode: After entering the mode menu in programming mode, you can change various parameters of the instrument. In the programming mode, you can zero and span calibration. Under normal circumstances, you can use the normal mode.

6.1.1 Conventional mode

Normal mode: The instrument enters the normal mode boot default. In the normal mode, the instrument has a real-time display of gas concentration measurement, the measuring data recording. Within this mode, you can display the battery power, gas type, current real-time concentration, concentration units, and time.

6.1.2. Programming mode

Programming Mode: In measurement mode, press [OK] key to enter the programming mode. 6 sub-menus display the programming mode, enter each menu, you can make various types of parameters.

Enter the programming mode, the cursor appears in the first item “Calibration” and press [up and down] keys to move the cursor to the next item, press the [OK] key to enter the submenu. Press [Back] key to return to the measurement mode.

There are six function main menu in programming mode, each for: parameter setting, gas calibration, alarm settings, language settings, history, system settings. And other functions. Main menu and sub-menu content in programming mode as follows:

Parameter setting

Gas calibration

Alarm settings

Language settings

History, system settings

System settings

1.Gas type 1.Zero 1.Lower value alarm Language setting 1.History record 1. Address setting
2. Decimal 2.Range calibration 2.High value alarm 2.Alarm record 2.Backlit light
3.Range 3.Restore default 3.STEL 3.Clear record 3.Backlit time
4.Gas unit 4.ADC value 4.TWA 4.Store interval 4.Time setting
5.Channel address 5.Calibrate period 4. Sound setting 5.Store capacity 5.Display definition
6.Display location 6.Vibrate alarm
7.Calibration time
8.Calibrate period

6.2 Instrument menu operation

6.2.1 Calibration settings

Instrument calibration mode is as follows: for each gas individually calibrated, select calibration channel by menu. Please adhere to calibration rules to calibrate, or may not succeed!

Zero calibration:

Calibration conditions: before zero calibration, put sensor in pure nitrogen for at least 60 s. Then in the calibration sub-menu to select the zero calibration, press [OK] key to pop up dialog box, select whether zero calibration (the default is no). Press [up and down] keys to select, “OK” to perform a zero calibration, press the [OK] key to zero calibration. If the buzzer starts sounding, it means the calibration was successful. At the same time dynamic displays the current value of the option ADC value, Zero calibration menu and dynamic display of current gas concentration values.

Range calibration: instrument needs to range calibration at the standard gas concentration.  Like the same as zero calibration, range calibration should be placed in standard gas for at least 60 s. Press [OK] key to pop up dialog box, select whether to scale calibration (the default is no). Press [up and down] keys to select, press “OK” to range calibration, press the [OK] key to range calibration hear the buzzer sounding which means range calibration was successful.

Restore Default: to restore calibration parameters to the factory set.

Note: Before calibrate to restore the default setting first

ADC value: dynamic display the current environment ADC value.

Note: Read-only cannot be modify the concentration values.

6.2.2 Alarm settings

Low alarm:

(1) Press [up and down] to select the location of figures, numbers from 0-9, and up to 9, press [up and down] key to return to 0;

(2) Press [ok] key to move the cursor to the next digit;

(3) Enter the desired number; press the [OK] key for 3 seconds to save the parameters, when you hear the buzzer sounding and the green index light is blinking means the data program is successful.

(4) If you do not want to modify the data, press the [return] key;

High alarm: high alarm and low alarm modification methods modify exactly the same way,

Note: The low alarm value cannot be greater than the high alarm value;

STEL alarm: STEL alarm modify method is exactly the same as the low alarm modify

TWA Alarm: TWA alarm modification method exactly the same as the low alarm modify

Sound settings:

(1) Press [up and down] key to select whether to turn off the buzzer sounds; ON buzzer is on, OFF is off the buzzer

(2) Press [OK] key to confirm modifying parameters;

Vibration alarm: vibration alarm modify method is exactly the same as sound settings modify.


6.2.4. History

(1) History: Press [up and down] key to scroll up and down to view.

Data format: Time (year, month, day, hour), concentration;

(2) Clear History: Clears all historical data measurement;

(3) Storage interval: Set a data recording interval (30-240), unit: seconds;

(4) Memory capacity: Displays the current historical data memory percentage share of total capacity;

6.2.5. Parameter settings

For Instrument displaying measured gas type, precision, and other parameters.

  1. Gas type: Select the type of gas detected.
  2. The decimal point: select the measurement accuracy. (Optional 0-4 decimal places)
  3. Gas range: modify the instrument range.
  4. Gas unit: Select the unit of measurement instrument. (PPM, mg / m³, % LEL, %, % VOL)
  5. SN: sensor number.
  6. TVOC: TVOC gas type. (Only for TVOC gas)

Note: This menu is encrypted and only factory technical personnel’s have the operating authority. The user only has read permissions.

6.2.6. System settings

It is used to set the address, the backlight parameters, time.

Address setting:

(1) Press [up and down] to select a digital value, from 0-9. When the digit goes up to 9, press [up and down] key to return to 0;

Note: The address range 1-255

(2) Press [OK] key to move the cursor to the next digit;

(3) Enter the desired number, press [OK] for three seconds to save the parameters. When you hear the buzzer sounding and the green index light blinking means the Data programming was successful

(4) If you do not want to modify the data, press the [return] key.

Backlight brightness:

(1) Press [up and down] key to adjust the backlight brightness level;

(2) Press [OK] to confirm the change backlight brightness;

(3) If you do not want to modify the data, press the [return] key.

Backlight time:

(1) Press [up and down] keys to adjust the backlight time;

Note: in minutes.

(2) Press [OK] to confirm the change backlight time;

(3) If you do not want to modify the data, press the [return] key.

Time setting:

Press [ok] key to set the time in hours to set an example, exactly the same as other settings

(1) Press [up and down] to increase the cursor up and down digits;

(2) Press [OK] key to move the cursor to the next digit;

(3) Enter the desired number; press [OK] for three seconds to save the parameters, when you hear the buzzer sounding and the green index light is blinking means Data programming was successful.

(4) If you do not want to modify the data, press the [return] key; after the time setting, press [return] key to return.

Instrument fault and trouble shooting

Fault The possible reason and resolution
Can’t start up Cause: battery power off, battery failure

Solution: charging and replace batteries

Reading too large or too small Reason: calibration failure, calibration error

Solution: recalibration

Sound, light, vibration alarm failure Reason: buzzer, LED, vibration alarm, buzzer port plug

Solution: contact customer service center, remove blockage

Instrument Programming unsuccessful Cause: Memory failure

Solution: Contact the company technician for tech support

Appendix: instrument alarm information:

Type Name Display Backlit LED Buzzer Vibrate Grade


Button operate NO Open No 1 short sound NO Highest 1
Operate successful Open Light 1 long sound 500 ms       2
Operate failure FALL open flash 2 short 300 ms 3




A1 value error E1 Open Flash  2 short sound 300 ms 4
A2 value error E2 Open flash 2 short sound 300 ms 5
Range value error E3 Open flash 2 short sound 300 ms 6
Zero calibrate error E4 Open Flash 2 short sound 300 ms 7
Range calibrate error E5 Open Flash 2 short sound 300 ms 8
TWA value error E6 Open Flash 2 short sound 300 ms 9
STEL value error E7 Open  Flash 2 short sound 300 ms 10


Turn off

Normal off Power OFF Open Light 1 long sound 500 ms 11
Lower power off Low OFF Open 1 long sound 500 ms 12
Storage fault F2 Open 300 ms 13
Data invalid F3 open 300 ms 14
Circuit abnormal F4 Open 300 ms 15
Outside IC fault F5 Open 300 ms 16
Probe abnormal F6 Open 300 ms 17
Communication abnormal F7 Open 300 ms 18
Power abnormal F8 Open 300 ms 19
Warning Calibrate expire D1 Open 300 ms 20
NO calibrate D2 Open 300 ms 21
Sensor expire D3 Open 300 ms 22
Sensor overload D4 open 300 ms 23
Over working scope D5 Open 300 ms 24
Battery low D7 Off NO 25
Record full D8 Open 300 ms 26







Over range OVER Open Flash 2 /s 300 ms 28
A2 or high alarm Red

Open Flash 2/s 300 ms 29
A1 or lower alarm Orange

Open Flash 1/s 300 ms 30
STEL alarm Red Flash

Open Flash 2/s 300 ms 31
TWA alarm Orange flash

Open Flash 1/s 300ms 32



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