Winsen MH-440D NDIR Infrared CH4 Gas Sensor User Manual

: June 8, 2024
: Winsen

Table of Contents

MH-440D NDIR Infrared CH4 Gas Sensor
Introduction
Features
Applications
Main Parameters
Struction Size
Output way.
Cautions for Maintenance
References
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NDIR Infrared CH4 Gas Sensor
MH-440D NDIR Infrared CH4 Sensor
(Model：MH-440D)
Manual
Version: 2.8
Valid from: 2020.10.16

MH-440D NDIR Infrared CH4 Gas Sensor

This manual copyright belongs to Zhengzhou Winsen Electronics Technology Co., LTD. Without the written permission, any part of this manual shall not be copied, translated, stored in database or retrieval system, also can’t spread through electronic, copying, record ways.
Thanks for purchasing our product. In order to let customers use it better and reduce the faults caused by misuse, please read the manual carefully and operate it correctly in accordance with the instructions. If users disobey the terms or remove, disassemble, change the components inside of the sensor, we shall not be responsible for the loss.
The specific such as color, appearance, sizes &etc, please in kind prevail.
We are devoting ourselves to products development and technical innovation, so we reserve the right to improve the products without notice. Please confirm it is the valid version before using this manual. At the same time, users’ comments on optimized using way are welcome.
Please keep the manual properly, in order to get help if you have questions during the usage in the future.

Introduction

MH-440D infrared gas sensor is a miniature universal intelligent sensor, which adopts NDIR theory to detect concentration of CH4 in air and has good selectivity, stable performance, long life, also is independent of Oxygen. The inside temperature sensor could be used for temperature compensation. This miniature infrared gas sensor is developed by the tight integration of mature infrared absorbing gas detection technology, micro machine workout and superior circuit design.
It is convenient in use and also instead of catalytic component directly, widely used in various occasions with flammable and explosion hazard gas.

Features

High sensitivity, high resolution, fast response
Output method: UART, analog voltage signal
Temperature compensation, excellent linear output
Excellent stability, Long lifespan
Anti-poisons, anti-vapor interference
Can replace catalytic type gas sensor directly

Applications

Widely used for HVAC refrigeration, air monitoring indoor, industrial-process control and safety protection, agriculture and animal husbandry.

Main Parameters

Fig1.Technical Parameters

Detection Gas	Methane (CH4)
Working Voltage	3.6-5V DC (Need to be powered by safety barrier)
Average Current	<85mA
Interface Level	3.0V
Detection range	0-10%vol(selectable, refer fig2.)
Output Signal	UART(3.0V)

Fig2.Measuring Range and Resolution

Target Gas| Molecular Formula| Measuring Range| Resolution| No. of decimal| Note
---|---|---|---|---|---
Methane| CH4| 05.00%VOL| 0.01%VOL| 2| Temperature compensation
010.00%VOL| 2
0100%LEL| 1%LEL| none

Struction Size

Winsen MH 440D NDIR Infrared CH4 Gas Sensor - Struction
Size

Pin definition

Pin 2-Vin power supply
Pin 1-GND
Pin 4-Vout (0.4~2V)
Pin 3-UART (RXD) 0~3.0V data input
Pin 5- UART (TXD) 0~3.0V data output

Output way.

6.1 Analog Output
The output of Vout is proportional to the gas concentration,0.4-2.0V output stands for 0 to full range.
Connection: Vin –5V, GND- Power Ground, Vout-ADC input.
After warm-up, Vout will show the voltage standing for the gas concentration.
If self-checking detects a fault, the output voltage is 0V.

6.2 Digital Output
Please refer MH-440D communication protocol.

Intrinsically safe explosion-proof

This product meets the standards of GB3836.1-2010 “Explosive Atmosphere Part 1: General Requirements for Equipment” and GB3836.4-2010 “Explosive Atmosphere Part 4: Equipment Protected by Intrinsically Safe “i”” standards”; the explosion-proof mark is Exib ⅡB T4 Gb, it is suitable for zone 1 and zone 2, contains Class IIA, T1-T3 explosive environment formed by the flammable gas, mixture of steam and air; it has passed the inspection by the National Quality Inspection Center for Explosion-proof Electrical Products and obtained the explosion-proof certificate.
When using, please note the following:
The intrinsically safe power supply must be used to power the sensor, otherwise the explosion-proof performance will be affected.
It is forbidden to replace the sensor in dangerous places.
It is forbidden to disassemble or replace the sensor element to avoid affecting the explosion-proof performance.
It is not allowed to replace components or structures, so as not to affect the explosion-proof performance.
The installation and wiring of the safety barrier must be carried out in accordance with the safety barrier instruction manual, and the safety barrier must obtain an explosion-proof certificate.

Connection diagram of intrinsically safe explosion-proof system
The on-site installation must comply with the relevant regulations of the GB3836.15—2000 “Electrical Equipment for Explosive Gas Environment Part 15: Electrical Installation in Hazardous Locations (Except Coal and Mines).

Winsen MH 440D NDIR Infrared CH4 Gas Sensor - proof
system

The distribution parameters of the connecting cable between the safety barrier and the sensor should meet:
Cc≤Co-Ci Lc≤Lo-Li Ui≥Uo Ii≥Io Pi≥Po

Note:
Uo: Maximum output voltage of safety barrier;
Io: Maximum output current of safety barrier
Po: Maximum output power of safety barrier
Co: Maximum external capacitance of safety barrier
Lo: the maximum external inductance of the safety barrier (see the safety barrier instructions for the above parameters book)
Cc: Maximum allowable distributed capacitance of connecting cable
Ui: sensor maximum input voltage
Ii: Maximum sensor input current
Pi: sensor maximum input power
Ci: Maximum internal capacitance of the sensor
Li: Maximum internal inductance of the sensor
Lc: Maximum allowable distributed inductance of connecting cable

Cautions for Maintenance

7.1 The sensor should be calibrated regularly. The suggested cycle time is 6 months.
7.2 Do not use the sensor in the high dusty environment for long time.
7.3 Please use the sensor with correct power supply.
7.4 Forbid to weld the sensor pins directly.
7.5 Forbid to cut the sensor pins.

Tel: 86-371-67169097
Fax: 86-371-60932988
Email: sales@winsensor.com
www.winsen-sensor.com
Zhengzhou Winsen Electronics Technology Co., Ltd.