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CO2 sensor | wall mounting | LED indicators | 24 V AC - V DC

Article code RSMFG-3
GTIN 14 5401003018859
Intrastat number 90.27.10.10
Category Room CO2 sensors
Current stock 2 U.
Factory lead time 5 Week(s)
Next arrival 25/07/2025 - 5 U.

Product description

This sensor detects temperature, humidity, CO2, and ambient light.

Measurement & Visualization: It measures temperature, humidity, CO2, and ambient light. Visual CO2 representation is provided via green, yellow, and red LEDs (with adjustable brightness).

Power & Data: The sensor operates on 24 VAC/VDC. Measurements are transmitted via Modbus RTU and three analog outputs (0-10V default).

Control & Configuration: Ventilation can be controlled based on room occupancy using ambient light detection.
All settings are configurable via Modbus RTU.

Applications: It's widely used for CO2 monitoring in places like schools, offices, and restaurants.

Additional specifications and description

 
 
 
Why is CO2 Concentration a Key Indicator for Occupancy and Ventilation, and What Values Does the Sensor Measure?
People produce CO2 or carbon dioxide while breathing. That makes CO2 concentration a good indicator for the occupancy and activity level in a space. The higher the occupancy or activity level, the more fresh air supply is required to maintain good indoor air quality. That is why in many applications, CO2 sensors are used as an indicator for the ventilation requirements. Next to CO2, this sensor also measures temperature, relative humidity and ambient light level. The measured temperature, relative humidity and CO2 level are available via the three analogue outputs and via Modbus RTU communication. The dew point and ambient light level are available via Modbus RTU communication.
 
How Do the Sensor's Three Analog Outputs Work, and Which Measurements Do They Transmit?
This sensor has three analogue 0-10 Volt outputs. Each of them transmits one of the measured values. E.g. by default, output 1 will transmit 0 Volt at 0 °C and 10 Volt at 50 °C. Each output value varies proportionally in function of the measured temperature, humidity or CO2 concentration. The measured temperature is available via output 1, relative humidity via output 2 and CO2 concentration via output 3. By default the output type is 0-10 Volt. Other output types can be selected via de Modbus holding registers.
 
How Do LED Indicators Visualize CO2 Levels, and How Can Their Settings Be Adjusted?
Wall mounting CO2 sensor
This HVAC transmitter offers a clear, visual indication of the CO2 level via the green, yellow and red LED. The green LED indicates that the CO2 level is within range - there is sufficient fresh air supply. When the CO2 level enters the alert range, the yellow LED lights up. Red means: CO2 out of range or insufficient fresh air supply. The ranges can be adjusted via the Modbus holding registers. The LED indicators can visualize the status of one of the three measured values, by default CO2.
 
What Are the Sensor's Power Supply and Wiring Requirements?
The cage clamp terminal blocks reduce wiring and installation time. They eliminate the need for routine maintenance and guarantee a reliable contact for solid or stranded wires. This sensor can be supplied with 24 V DC or with 24 V AC. It is intended for 3-wire connection. The ground of the output (GND) is internally connected to the ground of the supply voltage (V-). Make sure not to connect this common ground to other devices that are powered by a DC voltage. 
 
How Do Photoacoustic Sensor Technology and the ABC Logic Algorithm Function?
Photo-acoustic sensors are highly sensitive and specific, making them useful for the detection of various gases such as pollutants, trace gases and volatile organic compounds. The use of specific infrared wavelengths corresponding to the absorption lines of CO2 ensures that interference from other gases is minimised.
 
In contrast to transmissive NDIR sensors, photoacoustic NDIR sensors measure the energy absorbed by CO2 molecules. When the infra-red emitter is pulsed, CO2 molecules absorb infrared light on a regular basis. This causes additional molecular vibration, which results in a pressure wave within the measurement chamber. The higher the concentration of CO2, the more light is absorbed, and thus the amplitude of the acoustic wave increases. A microphone inside the gas chamber detects this, and the CO2 concentration can then be calculated. Photoacoustic NDIR sensing allows for much more miniaturisation of the measurement chamber. Furthermore, because sound waves are omnidirectional, the relative position of the emitter and microphone is unconstrained. Thus, photoacoustic NDIR sensors are typically more mechanically and thermally robust. 
 
The self-calibrating algorithm ABC logic is enabled by default. This algorithm is designed to be used in applications where CO2 concentrations drop to outside ambient conditions (400 ppm) at least once (15 minutes) in a 7-day period, which is typically seen during unmanned periods. The sensor reaches its operational accuracy after 25 hours of continuous operation at a condition where it is exposed to ambient reference levels of air with 400 ppm ± 10 ppm CO2.
 
How Is the Sensor Mounted Indoors, and What Should Be Considered for Optimal Performance?
This sensor can be installed indoors on a wall or on a surface. The mounting holes are adapted to standard European wall mounting boxes. The sensor can be attached to the wall mounting box with two screws. The sensor enclosure will cover the entire wall mounting box. To ensure optimal performance, the sensor should be protected from direct sunlight.
 
What Are the Design and Protection Features of the Sensor Enclosure?
The enclosure is designed for indoor use. It offers an IP30 protection against ingress of dust and moisture. The enclosure is exceptionally strong thanks to the use of high quality r-ABS plastic. Thanks to its contemporary modern design, this sensor can be used in most interior styles.
 

Remarks, reviews & ratings

19/06/2025
Werkt perfect om CO₂-niveaus te meten in ons kantoor. De LED-indicatie is duidelijk en handig in gebruik!
08/07/2024
Dizainas gal jau šiek tiek pasenęs, bet veikimas ir veikimo algoritmas be priekaištų.
24/01/2024
A sensor with free selectable temperature, relative humidity and CO2 ranges. All measured parameters and configuration are accessible via Modbus RTU. Innovative and easy to use.
06/11/2023
Easy to install and very reliable. The sensors are very accurate. Produced to high standards.
01/11/2023
Pros: -really low power consumption -automatic self-calibration -perfectly fit EU junction box Cons: -haven't been noticed yet
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