HDH-AL3 has been designed for monitoring of CO2 levels in room spaces. The transmitters have built-in three alarm LEDs (green/amber/red) for indicating high CO2 concentration. The transmitters have 2 x 0..10Vdc outputs for transmitting the CO2 measurement and the space temperature to BMS and control systems.

The unit has 3 alarm LEDs, green for normal concentration, amber for CO2 levels above 750ppm and red for CO2 levels above 1250ppm..

The CO2 transmitter is automatically calibrated using ABCLogic™. ABCLogic™ is a patented self-calibration technique, that is designed to be used in applications where concentrations will drop to outside conditions (appr. 400 ppm) at least twice in a week period (= an unoccupied building). For applications that do not see periodic ambient conditions, ABCLogic™ can be turned off, but a regular single point calibration of the sensor in 6 -12 months is necessary. Checking and calibration is recommended every 5th year even if ABCLogic™ is on.

• Accurate and reliable CO2 and temperature measurement
• Self-calibration of zero point via ABCLogicTM
• 3 Alarm LEDs for alerting high levels of CO2 (green/amber/red)
• 0..10Vdc Output for CO2 Concentration
• 0..10Vdc Output for Space Temperature
• 0..10Vdc Output for Relative Humidity (RH-models only)
• Modbus RTU Communication (M-models only)
• 24Vac/dc Power Supply