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° 。
|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|
|Tilt Error||< 1%|
< 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.)|
|Weight||850 g (30.0 oz) without cable|
|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.)|
|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.)|
Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.
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.
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.
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 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 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.
Yes. The signal from this sensor is not great enough to compensate for its dissipation because of the cable length.
As of June 2013, all of our current and retired net radiation sensors can be mounted using this kit. These include:
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.
Only one 4WPB100 is needed to measure the internal PRT in the radiometer.
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.
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：
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。
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：
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。
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.
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：
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。
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.
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.