top of page
< Back
Daviteq GHC03  Acetylene C2H2 Gas Sensor
LoRaWAN
Sigfox
Sub-GHz
NB-IoT

Daviteq GHC03 Acetylene C2H2 Gas Sensor

GHC03

Sản phẩm thay thế mới

SKU được thay thế

Satellite IoT

Phòng trưng bày

1. Giới thiệu

1.1 Overview

Daviteq GHC03 Acetylene C2H2 Gas Sensor module is intended for the automatic continuous measurement of hydrocarbons or carbon dioxide concentration in the atmosphere. The sensor operating principle is based on NDIR technology, i.e. on selective absorption of LED-produced infrared radiation by gas molecules. The differential dual wavelength method allows the elimination of water vapor, optical elements contamination, and other non-selective hindrances influence.

Daviteq GHC03 Acetylene C2H2 Gas Sensor module is designed to detect and monitor the presence of acetylene. The sensor operating principle is based on non-dispersive infrared (NDIR) technology, i.e. on selective absorption of LED-produced infrared radiation by gas molecules. Dual detector channels are used with a reference for background compensation. A temperature sensor is mounted for temperature compensation.

The sensor module is designed to be integrated with fixed gas detection systems. Their construction is a stainless steel flameproof enclosure with an integral stainless steel sinter for the safe entry of the gases being tested


The sensor module could be integrated with Wireless Devices such as Sub-GHz transmitter, Sigfox transmitter, LoRaWAN transmitter, RS485 output transmitters, etc.

Typical Applications: Flammable gas detection.


1.2 Specification



2. Nguyên tắc hoạt động

When infrared radiation interacts with gas molecules, infrared light is absorbed by the gas molecules at a particular wavelength, causing vibration of the gas molecules. NDIR (Non-Dispersive Infrared) gas sensors detect a decrease in transmitted infrared light which is in proportion to the gas concentration. This transmittance, the ratio of transmitted radiation energy to incident energy, is dependent on the target gas concentration.


NDIR gas sensor consist of an infrared source, detector, optical filter, gas cell, and electronics for signal processing. A single light source, dual wavelength type gas sensor has two detectors and two optical filters of different wavelengths which are placed in front of each detector. The infrared light that is absorbed by a target gas passes through the active filter with a particular bandwidth for the detection of the target gas. The infrared light that does not interact with the target gas passes through the reference filter. The difference between transmitted light intensities in these two bandwidths is converted into gas concentration. The dual wavelength sensor ensures stable measurements for a long period of operation as the aging effects of the light source or the gas cell are automatically compensated by output signals at the reference wavelength.

 

Mid-infrared radiation through sample gas causes a resonance of gas molecules at their natural frequency with the infrared light in the spectrum region where the energy level of infrared is equivalent to the natural frequency of gas molecules, resulting in the absorption of infrared by gas molecules in the form of molecular vibration.

The relationship between infrared transmittance and gas concentration is expressed by the Lambert-Beer law:



Where T is transmittance, I is the intensity of light passed through sample gas and an optical filter, Io is the initial light intensity emitted from the source, ε is the molar attenuation coefficient, c is gas concentration, and d is the light path length.

Because ε of the target gas and the light pass length d are fixed with an NDIR sensor, gas concentration can be measured by measuring the transmittance within the spectrum region of the absorbed energy (wavelength) by the target gas.


The initial light intensity emitted from the light source Io is preset by calibration using zero gas which does not absorb infrared light. The initial value of the molar extinction coefficient ε is set by calibration using calibration gas of known concentration.

3. Hiệu chuẩn

The Daviteq GHC03 Acetylene (C2H2) Gas Sensor must be connected to a reading device, it usually is a wireless transmitter like Sub-GHz, Sigfox, or LoRaWAN.

A. Why do we need to calibrate the gas sensor? There are some reasons:

- The output value of a sensor is different from the other sensor. It is not the same value for all sensors after manufacturing.

- The output value of a sensor will be changed over time.

Therefore, users need to calibrate the sensor before use or in a pre-defined interval time (30 months ).


B. How to calibrate the GHC03 Acetylene (C2H2) Gas sensor?

NOTE: THE CALIBRATION CAN ONLY BE DONE IN THE SAFE ZONE!!!


B.1 Instruction to connect the sensor head to gas standard cylinder

Please follow steps for Instruction to attach the calibration cap onto the sensor module to get Zero or Span values:


Step 1. Attach the calibration cap to the sensor head by turning the cap clock-wise.


Step 2. Installed the Regulator to the Gas cylinder

Note: Please select the flow regulator with a flow rate of 2.5 LPM or 5.0 LPM.


Step 3. Attach the tube to the regulator


Notes: The tube length is short as possible to reduce the gas loss.


B.2 Instruction for downlink the sensor's parameter


The sensor calibration is 2-point of auto-calibration via downlink. To write value for the parameter on the device

by downlinking the hex value, port 1 (default) from the network server/backend software to the device, follow below steps:

  1. Input the hex value on the network server/backend software.

  2. Initiate PARAMETER_UPDATE uplink message from the sensor by moving the magnet key to touch contact point on the sensor housing within 5 second as below figure. The device will be triggered to send uplink data to the gateway immediately, the purple LED will lit and then the downlink will be automatically sent from the network server/backend software.



B.3 Calibration process


Step 1: Write the concentration of the applied calibration standard C2H2 gas of the gas cylinder in the ""SPAN"" calibration routine, unit of %LEL (For example 20% LEL) via downlink. Details is in the section B.2- Instruction for downlink the sensor's parameter with relevant hex value.


Below are some sample hex downlink values for some typical LoRaWAN C2H2 concentrations in % LEL unit

The downlink value of 5A0441A000000005 for STD_GAS_LEVEL_FOR_SPAN of 20 % LEL

The downlink value of 5A04422000000005 for STD_GAS_LEVEL_FOR_SPAN of 40 % LEL

The downlink value of 5A04424800000005 for STD_GAS_LEVEL_FOR_SPAN of 50 % LEL

The downlink value of 5A04427000000005 for STD_GAS_LEVEL_FOR_SPAN of 60 % LEL

The downlink value of 5A0442A000000005 for STD_GAS_LEVEL_FOR_SPAN of 80 % LEL

The downlink value of 5A0442C800000005 for STD_GAS_LEVEL_FOR_SPAN of 100 % LEL



Step 2: Enable auto-calibration process by downlink

Enable calibration process by writing CALIB_PROCESS_ENABLE=1 via downlink hex value. Details is in the section B.2- Instruction for downlink the sensor's parameter with the hex value.

The downlink hex value of 5E02000100000005 for CALIB_PROCESS_ENABLE=1 of LoRaWAN C2H2 device


Step 3. Get the Zero value


Note: Keep the sensor Power ON all the time at least 30 minutes before calibration


  • Use the standard gas cylinder of Nitrogen 99.99% to supply the gas to the sensor;

  • Use the calibration cap as above pictures to attach to the sensor and connect the tubing to the gas cylinder;

  • Open the valve on the Cylinder slowly and make sure the gas has reached the sensor. The flow regulator should be 2.5 LPM or 5.0 LPM.

  • Enable zeroing process by writing ZERO_CALIB_ENABLE =1 via downlink hex value. Details is in the section B.2- Instruction for downlink the sensor's parameter with the hex value.

    The downlink hex value of 5802000100000005 for ZERO_CALIB_ENABLE =1 of LoRaWAN C2H2 device

  • Wait 120 seconds and turn OFF the valve to save the gas; ZERO_CALIB_ENABLE will be automatically reset to zero after 5 minutes.


Note:

Once sending data to the gateway by magnet key, the timer of sending time interval will be reset;

The shortest time interval between the two manual triggers is 98s. if shorter than 98s, there will be no data sending.


Step 4. Get the Span value


Note: 

Keep the sensor Power ON all the time at least 30 minutes before calibration.

Wait at least 5 minutes after zeroing process to implement the span process.


  • Use the Acetylene standard gas cylinder with a known concentration (for example Acetylene Air  0.5% is equivalent to 20% LEL ) to supply the gas to the sensor;

  • Use the calibration cap as above pictures to attach to the sensor and connect the tubing to the gas cylinder;

  • Open the valve on the Cylinder slowly and make sure the gas has reached the sensor. The flow regulator should be 2.5 LPM or 5.0 LPM.

  • Enable spanning process by writing SPAN_CALIB_ENABLE =1 via downlink hex value of (xxxxx). Details is in the section B.2- Instruction for downlink the sensor's parameter with the hex value.

    The downlink hex value of 5902000100000005 for SPAN_CALIB_ENABLE =1 of LoRaWAN C2H2 device

  • Wait 120 seconds and turn OFF the valve to save the gas. SPAN_CALIB_ENABLE will be reset to zero after 5 minutes.


Step 5: Disable auto-calibration process by downlink

Disable calibration process by writing CALIB_PROCESS_ENABLE =0 via downlink hex value of xxxxx. Details is in the section B.2- Instruction for downlink the sensor's parameter with the hex value. The downlink hex value of 5E02000000000005 for CALIB_PROCESS_ENABLE=0 of LoRaWAN C2H2 device.

4. Ghi chú ứng dụng

!
Widget Didn’t Load
Check your internet and refresh this page.
If that doesn’t work, contact us.

5. Installation Notes

Notes: If a sensor has been kept in transport containers at temperatures below zero centigrade, leave it at 1035 for not less than one hour.* if the Sensor is intended to install outdoors, please use a rain guard to protect the sensor from rain and direct sunlight. Please contact us to buy this accessory.

  • Place the sensor in the area to monitor the target gas concentration. Please always check the gas molecular weight v.s the air.

  • Do not use a damaged sensor. It must be repaired only by personnel authorized by the manufacturer.

  • Keep the sensor out of contact with aggressive substances, e.g., acidic environments, which can react with metals, and solvents, which may affect polymeric materials.

  • Do not allow sensors to fall on the floor. This could cause lamp filament breakage, damage to the pins and the gas entrance aperture.

  • Do not apply mechanical force against the gas entrance aperture.

  • Do not immerse sensors in water or other fluids.

  • Protect the gas entrance aperture against dust ingress and sprayed materials.

  • Anti-static handling precautions must be taken.

  • Diffusion holes of the sensor should be protected against the ingress of sprayed liquid or waterdrops, buy using the Splash guard or Rain guard.

  • The sensor is not intended to measure the target gas concentration contained in fluids.

  • Correct measurement is provided when the ambient temperature changes not faster than 0.6℃/ min.

  • Inspection and maintenance should be carried out by suitably trained personnel.

  • Persons, who have studied this guide, must be briefed on safety precautions when operating electrical equipment intended for use in explosive areas in due course.

  • When dealing with a cylinder containing a gas mixture under pressure, it is necessary to follow safety regulations.

  • There is no risk of pollution or negative impact on human health. The sensor does not contain any harmful substances that may be released during its normal operation.

6. Troubleshooting



7. Maintenance

Cleaning the Filter: Approx. 3-12 months

Check and clean the filter every few months, depending on the environment. Clean the filter with soft cloth and brush.


Re-calibration: Approx. 30 months

The gas sensor may be drifting over time. Please check the sensor specification to identify the interval time for the re-calibration sensor.

8. Cấu hình mặc định