Apogee infrared radiometers are the most accurate non-contact temperature sensors available anywhere. The sensors have tinned leads for connecting to a datalogger. Applications include measuring the temperatures of road surfaces, plant canopies, and soil, snow and water surfaces. Measurement of surface temperature is a crucial component of energy transfer. Accurate measurement of the leaf-to-air temperature gradient is essential to the determination of transpiration rate and stomatal conductance in both single leaves and plant canopies.
The SI-400 Series all have an SDI-12 digital output with individual field of views:
The SI-400 series sensors are available in a preconfigured IoT (Internet of Things) setup for continuous real-time canopy temperature and crop water stress index monitoring:
Apogee Instruments Infrared Radiometers (IRRs) measure surface temperature by converting thermal energy radiated from any surface in its field-of-view (FOV) to an electrical signal with a response time of 0.6 seconds. Each IRR carries an impressive uncertainty of 0.2°C at 95% confidence to ensure accurate measurements. The resilient 8-14 μm germanium window corresponds to the atmospheric window in order to minimise the effects of water bands below 8 μm and above 14 μm. The radiation shield, included free of charge with every IRR, insulates your sensor from rapid temperature changes, thus reducing noisy measurements. Multiple field-of-view (FOV) options range from half angles of 14, 18, and 22 degrees, for circular apertures, to 13 and 32 degrees for the vertical and horizontal half angles, respectively, of the horizontal aperture. The large range of calibrated target temperature, from -30 to 65°C, allows you to make accurate terrestrial measurements when the sensor body temperature is within 20°C of the target temperature. A durable clear anodised aluminium housing makes your sensor strong and lightweight, capable of withstanding extreme weather conditions.
Input Voltage Requirement | 4.5 to 24V DC |
Current Drain | 1.1 mA (quiescent), 6 mA (Transmitting) |
Calibration Uncertainty (-20 to 65°C) | 0.2°C, when target and detector temperature are within 20°C* |
Measurement Repeatability | < 0.05°C |
Stability (Long-term Drift) | Less than 2% change in slope per year when germanium filter is maintained in a clean condition |
Response time | 0.2s |
Spectral Range | 8 to 14 um; atmospheric window |
Operating Environment | -45 to 80°C, 0 to 100% relative humidity (non-condensing) |
Dimensions | 2.3cm diameter and 6.0cm length |
Mass | 190g (with 5m of lead wire) |
Cable | 5m of four conductor, shielded, twisted-pair wire. Additional cable available in multiples of 5m. Santoprene rubber jacket (high water resistance, high UV stability, flexibility in cold conditions). Pigtail lead wires. |
Warranty | 4 years |
*Excluding the SI-431, 0.3°C.
Field of View | 22° half angle |
Field of View | 18° half angle |
Calibration Uncertainty (-40 to 80°C) | 0.5°C, when target and detector temperature are different by more than 20°C |
Field of View | 14°C half angle |
Calibration Uncertainty (-20 to 65°C) | 0.3°C, when target and detector temperature are within 20°C |
Calibration Uncertainty (-40 to 80°C) | 0.5°C, when target and detector temperature are different by more than 20°C |
Field of View | 32° horizontal half angle; 13° vertical half angle |
Calibration Uncertainty (-40 to 80°C) | 0.5°C, when target and detector temperature are different by more than 20°C |