4分量研究级辐射表，内置热敏电阻和PT-100铂电阻
概览
CNR4为研究级的净辐射表，用于测量入射辐射能量与出射辐射能量之间的能量平衡。我们的数据采集器可以测量CNR4的这些输出。CNR4为科研级的能量平衡研究提供了专业的解决方案。
优势与特点
- Research-grade performance
- Meniscus dome on upper long-wave detector allows water droplets to easily roll off of it and increases field of view to nearly 180°
- Internal temperature sensors provide temperature compensation of measurements
- Drying cartridge helps keep the electronics dry
- Compatible with the CNF4 ventilation unit with heater that reduces formation of dew and melts frost
- Separate outputs of short-wave and long-wave infrared radiation for better accuracy and more thorough quality assurance
- Solar shield reduces thermal effects on the sensors
图像
技术说明
在结构上，CNR4含有一对朝上的短波辐射表和长波辐射表，以及镜像对称的一对朝下的短波辐射表和长波辐射。短波表和长波表分别测量短波辐射和远红外辐射。4个探头单独校准，具有各自的灵敏度系数。
CNR4的上部长波检测器含有新月形穹顶，使得水滴可以轻松的滚落。穹顶形状还增加了视野到接近 180° 而不是 150° 。
CNR4既含有内置的热敏电阻，也含有一个铂电阻，用于测量辐射表内部温度；通常使用热敏电阻测量内部温度，如果使用CR3000或CR5000，也可使用PT-100进行温度测量。
CNR4含有遮光盖用于减小对短波测量和长波测量的热效应。干燥剂筒让辐射表的电子部件保持干燥。可选的CNF4带加热通风单元，可以安装到CNR4，最小化露水的生成，以及除霜。
产品规格
| Sensor | Two thermopile pyranometers, two pyrgeometers, Pt100 RTD, and thermistor |
| Measurement Description | Measures incoming and outgoing short-wave and long-wave radiation |
| Response Time | < 18 s |
| Temperature Dependence of Sensitivity | < 4% (-10° to +40°C) |
| Sensitivity | 5 to 20 μV W-1 m2 |
| Non-Linearity | < 1% |
| Tilt Error | < 1% |
| Directional Error |
< 20 W m-2 (pyranometer) Angles up to 80° with 1000 W/m2 beam radiation |
| Operating Temperature Range | -40° to +80°C |
| Compliance | Conforms to the CE guideline 89/336/EEC 73/23/EEC. |
| Height | 6.6 cm (2.6 in.) dome-to-dome |
| Width | 11.1 cm (4.4 in.) |
| Length |
|
| Weight | 850 g (30.0 oz) without cable |
Pyranometer |
|
| Spectral Range | 305 to 2800 nm |
| Uncertainty in Daily Total | < 5% (The uncertainty values are for a 95% confidence level.) |
| Output Range | 0 to 15 mV (The output range is typical for atmospheric applications.) |
Pyrgeometer |
|
| Spectral Range | 4500 to 42,000 nm |
| Uncertainty in Daily Total | < 10% (The uncertainty values are for a 95% confidence level.) |
| Output Range | ±5 mV (The output range is typical for atmospheric applications.) |
兼容性
Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.
Additional Compatibility Information
Mounting
To avoid shading or reflections and to promote spatial averaging, the CNR4 should be mounted at least 1.5 m above the ground or crop canopy and away from all obstructions or reflective surfaces that might adversely affect the measurement.
The CNR4 can be attached to a vertical pipe or horizontal crossarm. To do this, first connect the radiometer to its mounting rod. The mounting rod then attaches to the pipe or crossarm via the 26120 Net Radiation Sensor Mounting Kit. The kit includes adjustment screws for leveling the CNR4. The 26120 can withstand winds up to 120 mph.
Data Logger Considerations
Four differential channels or four single-ended channels are used to measure the radiation components. A voltage excitation channel and an additional single-ended channel are required to measure the thermistor. If the RTD is used to provide the temperature compensation measurement, a current excitation channel (only available on the CR3000 and CR5000) and a differential channel are required.
相关技术文档
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CR1000X CNR4 Program Controlling the CNF4 Heater/Ventilator v.1 (4 KB) 17-10-2019
CR1000X program measures the CNR4 and controls the CNF4 heater/ventilator based on environmental conditions, and monitors the CNF4 tachometer. The program uses an EE181 temperature and relative humidity sensor and a 03002 Wind Sentry to provide the measurements for determining when to turn the fan and heater on and off. An A21REL-12 relay switches power to the CNF4.
CR1000X CNR4 Program using Thermistor v.1 (2 KB) 17-10-2019
CR1000X program that uses differential terminals to measure the four radiation outputs and one excitation terminal and one single-ended terminal to measure the thermistor. The program measures the sensors every 1 second, performs the online processing of the data, and stores processed data to a data table called cnr4_data once every 60 minutes. It also stores the raw time-series data from CNR4 to data table called cnr4_ts.
CR3000 CNR4 Program using Pt-100 v.1 (2 KB) 17-10-2019
CR3000 program measures the Pt-100 sensor for the body temperature of the CNR4. This program requires four differential channels to measure the four radiation outputs, one current excitation channel, and one differential channel for Pt-100 measurement. It measures the sensors every 1 second, performs the online processing of the data, and stores the processed data to a data table called cnr4_data once every 60 minutes. It also stores the raw time-series data from CNR4 to data table called cnr4_ts.
常见问题解答
CNR4-L: 11
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Yes. The signal from this sensor is not great enough to compensate for its dissipation because of the cable length.
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As of June 2013, all of our current and retired net radiation sensors can be mounted using this kit. These include:
- Current sensors: CNR4-L, NR-LITE2-L, and NR01-L
- Retired sensors: CNR1, CNR1-L, CNR2-L, NR-LITE-L, and Q7.1-L
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Only one 4WPB100 is needed to measure the internal PRT in the radiometer.
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Mount the net radiometer so that no shadow will be cast on it at any time of day from obstructions such as trees, buildings, the mast, or the structure on which it is mounted.
Campbell Scientific recommends installing a net radiometer in an open area, away from the main weather station structure on a separate vertical mast. If it is necessary to install this sensor on the main tall tower (30 ft or taller), the sensor should be installed at the top of the tower. In the northern hemisphere, the sensor should be facing south. In the southern hemisphere, the sensor should be facing north. If the tower uses a solar power system (that is, solar panels), ensure that the solar panels are installed away from the main tower.
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The CR1000 requires a 4WPB100 to measure the internal PRT. (Data loggers such as the CR3000 and CR5000 have the necessary PRT bridge module built in to measure the PRT.) Note that the CNR4-L also includes an internal thermistor, which can be directly measured by the CR1000. Because of this, when using a CR1000, Campbell Scientific typically recommends monitoring the internal temperature of the CNR4-L using its internal thermistor instead of the PRT.
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大多数 Campbell Scientific 传感器的型号中都带有 –L，它表示用户指定线缆长度。如果传感器型号名称列有 –LX (这里 “X” 是其它的某个字符), 那么该传感器需要用户指定长度，但线缆尾端会配有用于某个独特系统的特殊快速接头：
- –LC 表示用户指定线缆长度，所配快速接头用于 ET107, CS110, 或已停产的 Metdata1 系统。
- –LQ 表示用户指定线缆长度，所配快速接头用于 用于 RAWS-P 气象站。
如果一个传感器的主型号数字的后面没有被指定 –L 或其它的 –LX 字符，那么该传感器将具有固定的线缆长度。在产品页面订购栏中 (Ordering tab) 的描述字段的末尾，会列出线缆的长度。例如 034B-ET 型号的描述字段含有信息：Met One风传感器适用于ET气象站，67英寸线缆 (Met One Wind Set for ET Station, 67 inch Cable)。产品按固定的线缆长度做尾端处理，默认是尾线方式。
如果线缆尾端配有用于某个独特系统的特殊快速接头，则型号尾部的字符会指定该传感器用于哪一个系统。例如，034B-ET 型号表明该传感器是一个 034B 且用于 ET107 系统。
- 以 –ET 结尾的型号的传感器配备快速接头，用于 ET107 气象站。
- 以 –ETM 结尾的型号的传感器配备快速接头，用于 ET107 气象站，但它们也含有一个特殊的系统安装支架，在订购一个备件时，所配的支架经常是便捷实用的。
- 以 –QD 结尾的型号的传感器配备快速接头，用于 RAWS-F 快速配置气象站。
- 以 –PW 结尾的型号的传感器配备快速接头，用于 PWENC 预接线机箱或预接线系统。
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不是每一种传感器都有不同的线缆尾端选项。通过查找传感器产品页面的订购栏 (Ordering tab) 中的两个位置，可以检查某种特定传感器的可用的线缆尾端选项：
- 产品型号
- 线缆尾端选项列表
如果传感器以 –ET, –ETM, –LC, –LQ, 或 –QD 等版本的型号供应，那么线缆尾端选项已经反映在该传感器的产品型号中。例如，034B 以 034B-ET, 034B-ETM, 034B-LC, 034B-LQ, 和 034B-QD 等型号供应。
所有其它的线缆尾端选项，如果可用，会列在该传感器产品页面的订购栏 (Ordering tab) 中的线缆尾端选项 (“Cable Termination Options) 区域。例如，034B-L 风速风向传感器具有 –CWS, –PT, 和 –PW 等线缆尾端选项，显示在 034B-L 产品页面的 订购栏 (Ordering tab) 位置。
注： 当更新的产品添加到我们的库存中时，一般来说，我们会在单个传感器的产品型号下面列出多种线缆尾端选项，而不是创建多个产品型号。例如，HC2S3-L 具有 –C 线缆尾端选项用于连接到 CS110，而我们并没有使用 HC2S3-LC 产品型号。
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Because of the loss of IR radiation, nearly all thermopile instruments typically have a negative offset. This offset is most easily visible at night-time, when a small negative value is read instead of zero. This same offset is present during the daytime, but it is not as visible because of the large solar signal.
Another common issue involves leveling an instrument. Leveling a thermopile instrument can cause errors in the direct beam component because the cosine response is not correct. These errors are more notable when the sun is close to the horizon because the angle is so shallow.
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Campbell Scientific 的很多传感器都有可行的不同线缆尾端处理选项，包括以下几种：
- –PT (–PT w/Tinned Wires，镀锌尾线) 是默认选项，不显示在产品行中，而其它选项会显示在产品行中。线缆末端为尾线方式，可直接连接到数据采集器。
- 在 –C (–C w/ET/CS110 Connector，CS110快速接头) 选项中，线缆尾端所配的快速接头可连接到 CS110 电场计或 ET-系列的气象站。
- 在 –CWS (–CWS 带 CWS900 快速接头) 选项中，线缆尾端所配的快速接头可连接到 CWS-系列的接口。连接到 CWS900-系列接口使得传感器可被用于无线传感器网络中。
- 在 –PW (–PW 带预接线快速接头) 选项中，线缆尾端所配的快速接头可连接到预接线机箱上。
- 在 –RQ (–RQ 带RAWS 快速接头) 选项中，线缆尾端所配的快速接头可连接到 RAWS-P 永久配置远程自动气象站。
注： 线缆尾端选项的可行性因传感器而异。例如，传感器可能会有 无选项、两个选项或几个选项可供选择。如果预期的选项没有列在所指定的传感器中，请联系 Campbell Scientific 的应用工程师寻求帮助。
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Technically, because albedo is the fraction of the sun’s radiation reflected from a surface, albedo cannot be quantified at night.
When calculating albedo, it is important to remember that when radiation readings are very low, there is a significantly large error associated with the ratio. For example, as the sun drops to a lower position on the horizon, the ratio of reflected and incoming radiation becomes somewhat meaningless.
Albedo can be calculated from the simultaneous incoming and reflected pyranometer readings, with the average stored. Both of these pyranometer signals should be in a differential input mode.
- At night-time, the upper pyranometer faces a cold sky, which causes the domes to cool and the readings to be negative. (For example, there may be readings of -2 to -7 W/m2, depending on the sky conditions.)
- In contrast, the lower pyranometer faces the ground, which could be warmer or cooler. The readings are unlikely to be positive, and may even be -2 W/m2.
In principle, two negative values could result in a night-time albedo of 0.5.
Because of the input resolution, noise, and offsets of the data logger used, it is highly unlikely that any individual pyranometer reading is exactly zero. Depending upon the configuration used, any positive irradiation values recorded by the data logger as less than 2 W/m2 may, actually, be less than zero.
If an upper pyranometer reading, a lower pyranometer reading, or both is/are less than 2 W/m2, the albedo value should be described as “undefined” or “invalid.”
Another approach is to just not calculate albedo when the flux values get small. For example, set a cut-off point for the minimum flux value that will be used in albedo calculations.
If solar position is being calculated, one other approach is to use a solar position calculation, such as 1° above the horizon.
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