ATH Temperature and Relative Humidity Sensors
The ATH-2 range of temperature and humidity sensors are easy to maintain, with an exchangeable calibration chip to ensure accurate and reliable measurements over time. Available with either an analogue (ATH-2A) or SDI-12 (ATH-2S or ATH-VPD) output, these sensors are ideal for long-term installations.
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Humidity and temperature sensors available today come in varying degrees of quality – in ease of long-term maintenance, stability and durability. In response to the experiences of researchers and customers, the ATH range was developed to have greater instrument accuracy, easier upkeep, and an extended life. These sensors are ideally suited to in-canopy measurement and for use in the measurement of Vapour Pressure Deficit to predict the response of plants to environmental evaporative demand.
The ATH-VPD performs onboard Vapour Pressure Deficit calculations resulting in a sensor output available for VPD measurement and calculation with the ATH-VPD.
Questions of long-term drift and recalibration are often overlooked when purchasing a sensor. Drift is inevitable, and is caused by several factors including vibration, environmental contamination, or extreme temperature fluctuations. Previously, reducing inaccurate measurements (caused by sensor drift) meant undertaking a regular, time-consuming, preventative maintenance calibration program. The unique design of the ATH-2S, ATH-2A and ATH-VPD addresses these problems at the core – providing a user replaceable sensing chip which can be installed on-site with no downtime or return to manufacturer required.
The ATH-VPD additionally incorporates the following calculated values:
- Measured:
- Temperature °C.
- Air Humidity %.
- Air Pressure Pa.
- Calculated:
- Dew point °C.
- Water vapour density g/m3.
- Vapour pressure deficit Pa.
- Saturated vapour pressure Pa.
- Actual vapour pressure Pa.
Specifications
| Â | Â | ATH-2A | ATH-2S |
| Temperature | Range | -40 to 60 deg.C | -40 to 60 deg. C |
| Output Sensitivity | 10mV / deg.C | ||
| Accuracy | ±0.15 °C | ±0.15 °C | |
| Humidity | Range | 0 to 100% | 0 to 100 % |
| Output Sensitivity | 10mV/% | ±2% | |
| Accuracy | ± 2% | ± 2% | |
| General | Sensor Output | Analogue Voltage | SDI-12 |
| Power Requirements | 5.5 to 16V; 3 mA | NA | |
| Start-up Time | 1sec | NA | |
| Size | ø20 x 81 mm | ø20 x 81 mm | |
| Mesh Screen | 40 µm PE | Stainless Steel |
All versions of the ATH-2 include a replaceable calibration chip, cheaper than recalibration.
