Description
The HDH transmitters are specifically designed for measuring and controlling carbon dioxide concentration (CO2) and temperature in indoor spaces. These advanced sensors ensure accurate measurements, essential for applications in ventilation and air handling systems where air quality and temperature are crucial.
With the ABCLogic™ self-calibration method, possible long-term Sensor drift is eliminated, ensuring reliable and stable performance over the long term. In addition, the controller settings and option limits can be easily adjusted using the ML-SER tool, ensuring flexibility and convenience.
features
- Measurement of CO2 concentration and temperature for precise air quality control.
- ABCLogic™ self-calibration for accurate measurements without long-term drift.
- Settings and option limits adjustable via the ML-SER tool for flexible configuration.
- Ideal for ventilation and air handling systems in commercial and industrial environments.
The HDH transmitters provide reliable measurement and control solutions for optimal control of air quality and temperature, with a long service life and minimal maintenance requirements.
Technical data
| Additional measurements | No additional measurements |
| Power supply | 24 Vac/dc (22…28 V), < 2 VA |
| Time constant | < 2 minutes |
| CO₂ measuring range | 0…2000 ppm |
| CO₂ measuring accuracy | typ. ±40 ppm + 3 % of value |
| Temperature measuring range | 0…50 °C |
| Temperature measuring accuracy | ±0.5 °C |
| CO₂ output | 0…10 Vdc, 2 mA |
| Temperature output | 0…10 Vdc, 2 mA |
| Relay output | None |
| IP protection class | IP20 |
| Ambient temperature | 0…50 °C |
| Ambient humidity | 0…85 %rH |
| Product dimensions | 87 x 86 x 30 mm |
| Mounting | On the wall or on a flush-mounting box (screw hole spacing: 60 mm) |
| Material | ABS plastic |
Available versions
| Model | Description | |
|---|---|---|
| Category | Model | Description |
| HDH-PIR series | HDH-PIR (1135240) | CO₂ + temperature + presence |
| HDH-RH-PIR (1135250) | CO₂ + temperature + humidity (%rH) + presence | |
| HDH-M-PIR (1135260) | CO₂ + temperature + presence + modbus | |
| HDH-M-RH-PIR (1135270) | CO₂ + temperature + humidity (%rH) + presence + modbus | |
| With display (N models) | HDH-PIR-N (1135241) | CO₂ + temperature + presence + display |
| HDH-RH-PIR-N (1135251) | CO₂ + temperature + humidity (%rH) + presence + display | |
| HDH-M-PIR-N (1135261) | CO₂ + temperature + presence + modbus + display | |
| HDH-M-RH-PIR-N (1135271) | CO₂ + temperature + humidity (%rH) + presence + modbus + display | |
| Passive models | HDH-Passive | CO₂ and temperature, with passive temperature measurement (e.g. Pt1000 Sensor) for simple applications |
| Accessories and options | Potentiometers | Active (HD-PU) and passive (HD-P) |
| Indication LEDs | For CO₂ level (HD-AL3) | |
| Relay output | (HD-R) | |
| Configuration tool | ML-SER for settings and calibration |



