| SF-110 | SF-421. | |
|---|---|---|
| 测量范围 | -50 to 70 C | -50 to 70 C |
| 测量的不确定性 | 0.1 C (from 0 to 70 C), 0.2 C (from -25 to 0 C), 0.4 (from -50 to -25 C) | 0.1 C (from 0 to 70 C), 0.2 C (from -25 to 0 C), 0.4 (from -50 to -25 C) |
| Measurement Repeatability | Less than 0.05 C | Less than 0.05 C |
| Long-term Drift (Non-stability) | Less than 0.02 C per year (when used in non-condensing environments where the annual average temperature is less than 30 C, continuously high temperatures or continuously humid environments increase drift rate) | Less than 0.02 C per year (when used in non-condensing environments where the annual average temperature is less than 30 C, continuously high temperatures or continuously humid environments increase drift rate) |
| Equilibration Time | 10 s | 10 s |
| 自加热 | Less than 0.01 C (typical, assuming pulsed excitation of 2.5 V DC), 0.08 C at 5 C (maximum, assuming continuous input excitation of 2.5 V DC) | Less than 0.01 C |
| Operating Environment | -50到70 c;0至100％相对湿度 | -50到70 c;0至100％相对湿度 |
| Input Voltage Requirement | 2.5 V直流刺激 | 5.5至24 V DC |
| Output Voltage Range | 0 to 2.5 V DC (assuming input excitation of 2.5 V DC) | - |
| 电流消耗 | 0.1 mA DC（热敏电阻）在70℃（最大，假设连续输入激励为2.5 V DC） | 0.6 mA (quiescent), 1.3 mA (active) |
| Dimensions | 570 mm length, 21 mm pipe diameter, 70 mm disk diameter | 570 mm length, 21 mm pipe diameter, 70 mm disk diameter |
| Mass | 400 g | 400 g |
对植物的霜损伤可能对作物产量和质量产生大的影响。在霜冻事件期间保护作物取决于植物温度预测的准确性。通常，空气温度不是霜冻事件的时序，持续时间和严重程度的可靠预测因子，因为在某些环境条件下，植物冠层温度可以显着不同于空气温度。
在清晰，平静的夜晚，植物叶和花蕾温度可以下降到冷冻后，即使空气温度仍然在0℃高于（见下一页的图）。这被称为辐射霜，是由于表面附近的空气混合（风），并且表面上的负净龙波辐射平衡（从表面发射比表面吸收更多的长波辐射晴朗的天空）。在多云和/或有风的条件下，不会发生辐射霜事件。
bob体育竞技Apogee仪器叶和芽温度传感器均设计为近似植物叶和花蕾温度以预测霜冻事件。当空气温度将近冻结时，辐射霜探测器旨在用于裁剪领域和果园的应用，并且空气温度测量不是霜形成的良好预测因子。
Apogee Instruments leaf and bud temperature sensors consist of two precision thermistors, one combined with a simulated leaf and the other a simulated bud, in a single housing. The leaf sensor is designed to mimic a plant leaf and the bud sensor is designed to mimic a flower bud. Leaf and bud temperature sensors provide close approximations to leaf and bud temperatures and can be used for prediction of frost on leaves and buds. Detectors are weatherproof and are designed for continuous temperature measurement in the same environmental conditions plants are exposed to.
Leaf and bud temperature estimates in cropped fields, orchards, and vineyards. Leaf and bud temperatures returned by the detector can then be used to alert growers to the potential of frost damage to crops.
有用的文章和链接
Fruit Bud Damage from Cold Temperatures
Responding to Freezing Conditions
Frost/Freeze Protection for Horticultural Crops
Minimize Losses from Frost Using Direct Measurements - Campbell Scientific Post
Using Wireless Sensor Networks in Commerical Strawberry Production
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