Digital gas transmitter

Digital gas transmitter is an intelligent control product developed by our company, can output 4-20 mA current signal and real-time display gas value. This product has high stability, high accuracy and high intelligent characteristics, and through simple operation you can realize control and alarm to test area. At present, the system version has integrated 1 road relay. It's mainly used in the area need to detect carbon dioxide, can display the numerical indexes of detected gas, when detected gas index beyond or below pre-set standard, the system automatically do a series of alarm action, such as alarm, exhaust, tripping, etc. (According to user's different settings ).

Products Details

Technical Parameters

Transmitter Usage

1. Detection principle: This system through standard DC 24V power supply, real-time display and output standard 4-20mA current signal, analysis and processing to complete digital display and alarm operation. 2. Applicable objects: This system supports the standard sensor input signals. Table 1 is our gas parameters setting table (For reference only, users can set the parameters according to the needs) Table 1 Conventional gas parameters
Detected gas Measure Range Resolution Low/High Alarm Point
EX 0-100%lel 1%lel 25%lel   /50%lel
O2 0-30%vol 0.1%vol 18%vol, 23%vol
N2 70-100%vol 0.1%vol 82%vol, 90%vol
H2S 0-200ppm 1ppm 5ppm  /10ppm
CO 0-1000ppm 1ppm 50ppm  /150ppm
CO2 0-50000ppm 1ppm 2000ppm /5000ppm
NO 0-250ppm 1ppm 10ppm  /20ppm
NO2 0-20ppm 1ppm 5ppm  /10ppm
SO2 0-100ppm 1ppm 1ppm   /5ppm
CL2 0-20ppm 1ppm 2ppm  /4ppm
H2 0-1000ppm 1ppm 35ppm / 70ppm
NH3 0-200ppm 1ppm 35ppm / 70ppm
PH3 0-20ppm 1ppm 1ppm / 2ppm
HCL 0-20ppm 1ppm 2ppm   /4ppm
O3 0-50ppm 1ppm 2ppm   /4ppm
CH2O 0-100ppm 1ppm 5ppm   /10ppm
HF 0-10ppm 1ppm 5ppm   /10ppm
VOC 0-100ppm 1ppm 10ppm   /20ppm
3. Sensor models: Infrared sensor/catalytic sensor/electrochemical sensor 4. Response time: ≤30 seconds 5. Working voltage: DC 24V 6. Using environment: Temperature: - 10 ℃ to 50 ℃ Humidity < 95%( No condensation) 7. System power: maximum power 1 W 8. Output current: 4-20 mA current output 9. Relay control port: Passive output, Max 3A/250V 10. Protection level: IP65 11. Explosion-proof certificate number: CE20,1671, Es d II C T6 Gb 12. Dimensions: 10.3 x 10.5cm 13. System connecting requirements: 3 wire connection, single wire diameter 1.0 mm or more, line length 1km or less.

Wiring instructions

The internal wiring of the instrument is divided into display panel (upper panel) and bottom panel (lower panel). Users only need to connect the wiring on the bottom plate correctly. Figure 2 is the diagram of the transmitter wiring board. There are three groups of wiring terminals, power communication interface, alarm lamp interface and relay interface.

Display transmitter's factory appearance is like figure 1, there has mounting holes on the transmitter rear panel. The user only need to connect line and other actuator with the corresponding port according to the manual, and connect DC24V power, then it can work.

Functional operation instructions

5.1 Panel description As shown in Figure 5, The transmitter panel is composed of a concentration indicator, a digital tube, a status indicator lamp, a first class alarm indicator lamp, a two level alarm indicator lamp and 5 keys. This diagram shows the studs between the panel and the bezel, After removing the bezel, observe the 5 buttons on the panel. Under normal monitoring condition, the status indicator flashes and the digital tube shows the current measurement value. If the alarm situation occurs, the alarm light indicates level 1 or 2 alarm, and the relay will attract.

Figure 1 Appearance

Figure 2 Internal structure

Client interface connection: (1)Power signal interface: "GND", "Signal" , "+24V". The signal export 4-20 mA 4-20mA transmitter wiring is like figure 3.

Figure 3 Wiring illustration

Note: For illustration only, the terminal sequence is not consistent with the actual equipment. (2)Relay interface: provide a passive switch export, always open, alarm relay pull up. Use as needed.Maximum support 3A/250V. Relay wiring is like figure 4.

Figure 4 Relay wiring

Notice: It is need to connect AC contactor if user connect big power control device.

Figure 5 Panel

5.2 User instructions 1. Operation procedure Set parameters First step: Press the settings button, and the system displays 0000 User instructions Second steps: Input password (1111 is password). The up or down button allows you to select between 0 and 9 bits, press the settings button to select the next one in turn, Then, select the numbers by using the "up" button Third steps: After input password, press the "OK" button, if the password is correct then the system will enter the function menu, digital tube display F-01, through the "turn on" key to select the function of F-01 to F-06, all the functions in the function table 2. For example, after selecting the function item F-01, press the "OK" button, and then enter the first level alarm setting, and the user can set the alarm at the first level. When the setting is complete, press the OK key, and the system will display F-01. If you want to continue setting, repeat the above steps, or you can press the return key to exit this setting. The function is shown in table 2: Table 2 Function description





Primary alarm value



Second alarm value






Resolution ratio






Gas type


2. Functional details ● F-01 Primary alarm value Change the value through the "up" button, and switch the position of the digital tube flashing through the "Settings" key. Press OK to save settings. ● F-02 Second alarm value Change the value through the "up" button, and switch the position of the digital tube flashing through the "Settings" key. Press OK to save settings. ● F-03 Range Values(Factory has been set, please do not change) Maximum value of instrument measurement ● F-04 Resolution ratio (Only read) 1 for integers, 0.1 for one decimal, and 0.01 for two decimal places. Functional details● F-05 Unit settings(Only read) P is ppm, L is %LEL, and U is %vol.  F-05 Unit settings(Only read)F-05 Unit settings(Only read)2 ● F-06 Gas type(Only read) Digital Tube Display CO2 3. Error code description ● E-01 Over full scale 5.3 User operation Precautions In the process, the user will set the parameters, 30 seconds without pressing any key, the system will exit the environment of setting parameters, back to the detection mode. Note: This transmitter does not support calibration operation. 6. Common faults and handling methods (1) System no response after power is applied. Solution: Check whether the system has electricity. (2) Gas stable display value is beating. Solution: Check if the sensor connector is loose. (3) If you find the digital display is not normal, turn off the power a few seconds later, then turn on.

Important point

1. Before using the instrument, please read the manual carefully. 2. The instrument must be operated in accordance with the rules specified in the instructions. 3. The maintenance of the equipment and the replacement of parts is responsible for our company or around the repair station. 4. If the user does not follow the above instructions without authorization to start repairing or replacing parts, the reliability of the instrument is responsible for the operator. The use of the instrument should also comply with the relevant domestic departments and factories within the instrument management laws and regulations.

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