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

Article code RSMFH-3
GTIN 0.540.100.301.886.6
Intrastat number 90.27.10.10
Category Room CO2 sensors
Current stock 4 U.
Factory lead time 5 Week(s)

Product description

Temperature, relative humidity, CO2, and ambient light level are all measured by this room transmitter. The CO2 level is visually indicated by the green, yellow, and red LED indicators.

The supply voltage is 24 V DC and can be connected using either the terminal blocks or the RJ45 connector. The measured values are communicated via three analogue outputs and Modbus RTU.
The output type is set to 0-10 V by default but various output types are available. Ambient light detection is used in many applications to control the ventilation system based on the occupancy of the room. Modbus RTU communication allows for the adjustment of all settings.

The CO2 sensor element can be replaced. The light intensity of the LEDs used for status indication can also be adjusted. This CO2 meter is commonly used in schools, office buildings, restaurants, and other public places to measure carbon dioxide levels and to ensure that adequate fresh air is supplied into the room.

Additional specifications and description

Is there sufficient fresh air supply?
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.
 
Three analogue outputs to transmit the measured values
This sensor has three analogue 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. 
 
Visual indication of the measured value
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 that CO2 levels are too high or that there is insufficient fresh air supply. The ranges can be adjusted via the Modbus holding registers. The LED indicators can visualise the status of one of the three measured values, but is set to CO2 by default.
 
RJ45 socket or terminal blocks?
This sensor offers you the choice to connect it via the cage clamp terminal blocks or via the RJ45 connector. Supply voltage and Modbus RTU communication can be connected via the RJ45 connector. Via the terminal blocks it is possible to connect the outputs, Modbus RTU communication and the supply voltage. Never connect the supply voltage via the RJ45 connector and the terminal blocks simultaneously. The supply voltage is 24 V DC. The ground terminals of the power supply (V-) and output (GND) are internally not connected. This means that a 4-wire cable is required to connect this sensor. Most 24 V DC power supplies offer protection against short circuit, overload and overvoltage. A 24 V DC supply voltage increases the safety and reliability of your installation. 
 
Photo-acoustic NDIR sensor element - ABC logic
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.
 
Surface mounting How to install a CO2 sensor
This sensor can be mounted on a wall or a surface indoors. The mounting holes are designed to accommodate standard European wall mounting boxes. Two screws are required to secure the sensor to the wall mounting box. The sensor enclosure will completely enclose the wall mounting box. To ensure peak performance, keep the sensor out of direct sunlight. 
 
Enclosure with contemporary design
The enclosure is designed for indoor use. It offers an IP30 protection against ingress of dust and moisture. The enclosure is designed and manufactured in-house in Sentera Plastics. It 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.

∞ Monitoring air quality

How a CO2 sensor works

Remarks, reviews & ratings

22/03/2024
Na ką pabandysime naująją versiją, jau sumontavau objekte, bus matyt kaip veiks, man patiko H versija nes nereikia sukti galvos koks pajungimas bus sistemoje čia galimybė ir taip ir taip pajungti.
11/12/2023
Информацията за нивата на СО2 в затворени помещения става все по-актуална особено през зимата. Този сензор осигурява прецизни показания, а наблюдението в реално време чрез приложение е изключително полезно.
07/12/2023
Der CO2-Sensor hat meine Erwartungen mit seinem modernen Design und seinen präzisen Messwerten übertroffen. Seine Echtzeit-Überwachung über Senteraweb gibt Sicherheit und macht ihn zu einer unverzichtbaren Ergänzung für alle, denen die Luftqualität in Innenräumen wichtig ist.
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