Product Name: Industrial Grade NDIR Gas Sensor Item No.: SRH, SJH, SBH, SBrH Series Version: V0.4 Date: September 18, 2020

1. In the technical parameters, the working voltage is changed from "3.5-6vdc" to "3.3-5.5vdc"; 2. The correction of 5v-2.5v level switching circuit in the circuit diagram is recommended. 1. Update product specification. 2. Add UART-TTL to RS232 transfer in the circuit diagram.

Industrial Grade NDIR Gas Sensor SRH, SJH, SBH, SBrH Series SBrH Series ▪ Carbon dioxide gas leakage ▪ Refrigerant leak sensor storage, cold-chain packaging) storage ▪ Underground garage ▪ Hydroponic culture Description Industrial grade NDIR gas sensors are adopted non-dispersive Infrared (NDIR) technology, made by advanced technology and elements, so they have splendid features and are widely used to detect concentration of CO2, CH4, C3H8, CBrH3 in both industry and agriculture applications. Industrial grade NDIR gas sensors can be easily integrated in safety and alarming devices, able to be...

Principle of Measurement Non-dispersive Infrared (NDIR) Principle Molecule like CO2 and CH4 is composed of different types of atoms, it has absorption spectrum in infrared range. Absorption intensity abides by Lambert-Beer’s Law. When light wave corresponded to certain gas with absorption spectrum passes through measured gas, the intensity of light wave will be significantly weakened. The intensity attenuation is related to concentration of measured gas. This relation follows Lambert-Beer’s Law. Basic working principle of NDIR sensor is as below. Basic mathematical model ： A majority of both...

Technical Parameters Configuration Table Sensor Type Concentration Range Temperature or Humidity Compensation Temperature Sensor Humidity Sensor Auto Baseline Calibration 2 Carbon Dioxide Propane Methyl Bromide/ Bromomethane 1. Humidity sensors have high humidity alert mechanism and reliable fail-safe operation: when relative humidity>95%, the light source is lit immediately, the sensor heats up to prevent condensation and protect itself, concentration output will be 0; when relative humidity <90%, high humidity abnormality alert quits, sensor will go back to normal work. 2. ABC（Auto Baseline...

Technical Specification Sensor Type4 Carbon Dioxide ≤ ±25ppm or 10% of reading, larger value as criteria 0～1%：≤ ±0.1%vol 0～1%：±0.06%vol 1%～5%：≤ ± (0.05%+5% of 1～2.5%: ±6% of Reading reading) 2.5%～full range: ±6% of 5%～full range:≤ ±10% of Reading reading Maximum Response Full Scale Point Repeatability8 Zero Drift7 Working Temperature Storage Temperature Working Voltage Working Current 1. 30~130kPa 2. All data can be ensured at pressure 101 kPa Peak Current Output Type Refer to Configurations Table Body material Stainless Steel Ex-proof Level 4. Sensor type with XD is the sensor with dimension...

Configuration & Pin Definition 1. Appearance Size Non-XD Type Sensor Height: 19mm (See Configuration Table) Matching Jack Matching Jack XD Type Sensor Height 16.6mm (See Configuration Table) Matching Jack 2. Pin Definitions Pin Description Power Input（Vi：DC3.3V～5.5V（Recommend Vi=5V） Power Input Terminal (Ground Terminal) Serial Port Terminal (Circuit Board Serial Port Sender) Voltage Output Terminal Serial Port Terminal (Circuit Board Serial Port Receiver) Appearance Size Notes 1. All dimensions in millimeters; dimensions without limits are nominal. 2. Body dimensional tolerances ±0.2 mm.

Typical Application Circuit Diagram Application Scenario 1: UART Serial Port Output External devices can communicate with sensors through UART. 3.3V device (CPU) can be connected with serial port pin RX and TX directly. The interface circuit is as follows, reading gas concentration data or performing calibration function. Picture 1: UART Communication Connecting Circuit

Typical Application Circuit Diagram Application Scenario 2: UART-TTL to RS232 When connecting external circuit, computer circuit is illustrated below: Baud Rate：9600bps Data Bit：8 Stop Bit：1 Check Bit：null Picture 2: UART-TTL to RS232 Circuit

Typical Application Circuit Diagram Application Scenario 3：5V-2.5V Level Switching Circuit Sensor need to transform the voltage when connecting with 5V devices, the interface circuit is as follows: Picture 3: 2.5V Communication Level Converted to 5V Communication Level Circuit

Typical Application Circuit Diagram Application Scenario 4：Voltage Output Sensor Pin D (Vout) output signal is 0-2.5V DC voltage, where 0.4-2.0V corresponding to 0-100% full range gas, the user can convert the voltage signal to industrial standard 4-20mA current signal through voltage current converter. The interface circuit is as follows: Picture 4: Analogue signal output circuit

Precautions for Use 1. Working temperature: - 40 ℃ ~ 70 ℃ 2. The connecting cable shall be shielded cable with insulating sheath, and its shielding layer shall be grounded. 3. Users should not replace the components of this product without authority. To avoid damaging product, please kindly solve the problems in operation with our engineers. 4. Installation, use and maintenance of this product should comply with relevant provisions of product instruction, GB3836.13-1997 "Electrical equipment for explosive gas environment Part 13: Explosion Overhaul of electrical equipment for explosive gas environment...

Communication Protocol 1.General Statement 1) The data in the protocol are all hexadecimal data, such as “46” is hexadecimal [70]. 2) [xx] is single-byte data (no symbol, 0-255); (xx) is dual-byte data, signed integer ( -32768 to +32767), the high-byte is ahead. Note behind “--” is annotation. 3) The byte length of entire command is [LB]+3. 2. Communication Protocol Format Send： [IP] [LB] [CMD] [DF] [CS] [IP] followed byte length does not include CS the command with parameter items and optional items Response： 1． When the command is implemented correctly, it responds [ACK] [LB] [CMD] [DF] [CS]...