NDIR Infrared CH4 Gas Sensor （Model：MH-441D） Manual Version: 1.1 Valid from: 2022.12.01 Zhengzhou Winsen Electronics Technology Co.,

Statement 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...

Zhengzhou Winsen Electronics Technology Co., Ltd. MH-441D NDIR Infrared CH4 Sensor 1. 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...

Zhengzhou Winsen Electronics Technology Co., Ltd. Fig2.Measuring Range and Refrigerant conversion factor Target Gas Molecular Formula Measuring Range Temperature compensation 5.Struction Size(Tolerance of unmarked dimensions is ±0.2) 6.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: V+ –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. Output concentration = Full range value...

Zhengzhou Winsen Electronics Technology Co., Ltd. 6.2 Digital Output Connections: Vin-5V power, GND- Power Ground, RXD - TXD of detector, TXD - RXD of detector. Users must use TTL level, if you use RS232 level, it must be changed. Detectors can read gas concentration via UART interface of sensor, no need to calibrate. UART Communication Protocol General setting Baud rate Data bit Stop bit Check bit Command: Every command includes 9 bytes from byte0 to byte8 The start byte is 0xff The command includes sensor no and it is 0x01 by default. The command is ended with checksum. 0x86 To read gas concentration...

Zhengzhou Winsen Electronics Technology Co., Ltd. Calculation method as follow: 1. except byte0, to add all of other bytes 0x1 + 0x86 + 0x00 + 0x00 + 0x00 + 0x00 + 0x00 = 0x87 2. negate to above value: 0xFF – 0x87 = 0x78 3. add 1 to above value 0x78 + 0x01 = 0x79 Eg. char getCheckSum(char *packet) { char i, checksum; for( i = 1; i < 8; i++) { checksum += packet[i]; } checksum = 0xff – checksum; checksum += 1; return checksum; } 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...

Zhengzhou Winsen Electronics Technology Co., Ltd. Danger Zone Safety Zone Safety Barrier 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...