Additional specifications and description
NDIR sensor technology and LED indicators
People produce CO2 or carbon dioxide while breathing. That makes CO2 concentration a good indicator for the occupancy and activity level in a space. In many applications, CO2 sensors are used as an indicator for the ventilation requirements. 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 measured temperature, relative humidity, CO2 and ambient light level are available via Modbus RTU. NDIR or Non-dispersive Infrared technology is used to measure the CO2 level. This technology offers a low life-cycle cost and a precise and stable long-term operation.
How to control fresh air supply?
The output of this sensor can control an EC fan, an AC fan speed controller or a damper actuator. The output value varies proportionally in function of the measured temperature, humidity and CO2 concentration. When more fresh air is required, the sensor will increase the fan speed or open the damper.
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 VDC. 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 VDC power supplies offer protection against short circuit, overload and overvoltage. A 24 VDC supply voltage increases the safety and reliability of your installation.
This sensor doesn't require any configuration. Once installed, it is ready to use. The default settings will do for most applications. If necessary, the settings can be adjusted via Modbus RTU. For example, a different output type can be selected to make it compatible with other devices: 0-10 VDC / 0-20 mA / 0-100 % PWM / Modbus RTU. Also the light intensity of the LEDs for status indication is adjustable. The Modbus register map provides a complete overview of all adjustable settings.
Self-calibrating to compensate sensor drift
The ABC logic self-calibrating algorithm is by default enabled. This algorithm is designed to be used in applications where CO2 concentrations will drop to outside ambient conditions (400 ppm) at least one time (15 minutes) in a 7day period, which is typically seen during unoccupied periods. The sensor will reach its operational accuracy after 25 hours of continuous operation at a condition that it was exposed to ambient reference levels of air at 400 ppm ± 10 ppm CO2.
The enclosure offers an IP30 protection against ingress of dust and moisture. It can be mounted on a wall indoors. To ensure optimal performance, it should be protected from direct sunlight.