The H-Guard is a CO2 transmitter series designed to be installed in HVAC applications. The CO2 sensing element uses the Non-Dispersive Infrared Technology (NDIR) with the patented self-calibration system to guarantee the long term stability and up to 15 years life time.

| Gas detected | Carbon Dioxide (CO2) |
| Sensing element | Non-Dispersive Infrared Detector (NDIR) |
| Accuracy | @25(77),2000ppm ±40ppm + 3% reading |
| Stability | <2% of FS over life of sensor (15 yr typical) |
| Calibration interval | ABC Logic Self Calibration System |
| Response time | <2 minutes for 90% step change |
| Warm up time | 2 hours (first time) 2 minutes (operation) |
| CO2 measuring range | 0-2,000ppm / 0-5,000ppm selectable in orders 0-20,000ppm / 0-50,000ppm just for TSM-CO2-S series |
| Sensor life | Up to 15 years |
| Power supply | 24VAC/24VDC |
| Consumption | 1.5 W max. ; 0.8 W avg. |
| Analog outputs | 0~10VAC or 4~20mA selectable by jumpers |
| Relay output | 1X3A switch load Four set points selectable by jumpers |
| Modbus interface | Modbus RS485 interface 9600/14400/19200(default)/28800 or 38400bps (programmable selection), 15KV antistatic protection. |
| Operation conditions | 0~50(32~122); 0~95%RH, non condensing |
| Storage conditions | -40~70(-40~158) |
| Net weight | 180g |
| Dimension | 100mm×80mm×28mm |
| Installation standard | 65mm×65mm or 2”×4”wire box |
| Approval | CE-Approval |