AN-009 Cross-sensitivity compensation method of LARK-1 CO sensor responding to CO2 EN

AN-008 EN LARK-1 4-20mA MODBUS PROTOCOL 2022-06-14

The LARK-1 sensor can communicate with a host device via an RS232 interface. We developed RS232-RS485 MODBUS Converter with 4-20mA analog output for LARK-1 in order to speed up users’ development speed. RS232 of the converter is terminated with LARK-1. The Modbus terminal and 4-20mA analog output is connected to host device. This application note shows how to operate LARK-1 via Modbus protocol using this converter and obtain gas concentration via 4-20mA analog output.

AN-007 LARK-1S MODBUS PROTOCOL EN 2022-06-20

The LARK-1S sensor can communicate with a host device via an RS485 interface. This application note shows how to operate LARK-1S with Modbus protocol, including sensor information inquiring, data logging, ZERO and SPAN calibration

AN-006 How to Get VOC Gases with Gas Sampling Bags EN 19-11-07

LARK-1HR i-C4H8 (high-resolution isobutylene) is a NDIR sensor developed by Promisense, which can be used to detect the concentration of various VOCs, including benzene, toluene, xylene, methanol, n-hexane and so on. In other words, VOC gas sensors could be calibrated with isobutylene. We measured the cross response of LARK-1HR i-C4H8 to various VOCs and presented cross sensitivity data in AN-005.

AN-005 Cross-Response of LARK-1 i-C4H8 to HC EN 20-09-27

LARK-1HR i-C4H8 (high-resolution isobutylene) is a NDIR sensor developed by Promisense, which can be used to detect the concentration of various VOCs, including benzene, toluene, xylene, methanol, n-hexane and so on. In other words, VOC gas sensors could be calibrated with isobutylene.

AN-002 Effect of Humidity on NDIR LARK-1 CH4 Reading EN 19-11-22

The NDIR gas sensor generally presents the range of gas humidity in datasheet which can ensure the normal performance of sensors. High humidity will not damage the sensor with no condensing. But it will increase error between Reading of sensor and concentration of target gas. Taking methane gas sensor as an example, in the case of high humidity, the Reading of sensor is generally higher than gas concentration. We pumped gases with different humidity into NDIR LARK-1 CH4 and analyzed the experimental data to study effect of humidity on Reading.

BlueCAL

Please read this user guide before evaluating the product. In order to get accurate sensor reading, please operate and calibrate LARK-1 according to this document.

ModbusCAL

ModbusCAL

Effect of Humidity on NDIR LARK-1 CH4

If the high humidity gas is injected into the non-working LARK-1 CH4, condensate water will be generated inside the sensor, which may cause short circuit of electronic components and damage the sensor. If LARK-1 CH4 sensor is used in high humidity environment, it is better to consider dehumidification, such as flue gas emission, underground pipeline gallery, or tropical rain forest area.

Infrared gas sensor

Non-Dispersive Infra Red (NDIR) sensor is an optical gas sensor composed of infrared source, optical path (Optics Cell), infrared detector (IR Detector), circuit (Electronics) and software algorithm (Algorithms). It is mainly used for the determination of compounds, such as CH4, CO2, N2O, CO, CO2, SO2, NH3, ethanol, benzene, etc., and contains most organic compounds (HC), including organic volatile compounds (VOC).