在高容积电导率土壤中的精度更高
概览
CS650 是多参数智能传感器，使用革新的技术监测土壤体积含水量、容积电导率和土壤温度。它的信号输出方式为SDI-12，可用于 Campbell Scientific 大多数数据采集器。
备注：如果用于ET107气象站，请选择CS650-LC 。
优势与特点
- 更精确的土壤含水量测量，容积电导率可达 3 dS m-1，无需实施特定土壤校准
- 更大的采集体积，减少了误差
- 对土壤质地和电导率的影响进行测量修正
- 估算很多种矿质土类型土壤中的含水量
- 多功能的传感器 — 可测量介电常数、容积电导率（EC）和土壤温度
图像
技术说明
CS650含有连接到印刷电路板的2根30 cm长的不锈钢探针。电路板用环氧树脂封装，附着在电路板的带屏蔽线缆提供与数据采集器的连接。
CS650测量传输时间、信号衰减和温度；再从这些原始测量值解析得到介电常数、体积含水量和容积电导率。
测量的信号衰减是用于反射检测的损失效应及传播时间的修正。损失效应修正可以让探头在容积电导率 ≤3 dS m-1 的土壤中，测量出高精度的体积含水量，并不需要实施特定的土壤校准。
由衰减测量还可以计算得到土壤容积电导率。靠近环氧树脂表面的与探针保持热接触的热敏电阻用来测量温度。如果传感器水平安装，可以得到与土壤含水量测量相同深度的精确温度测量。如果以其它的方位安装传感器，那么温度测量只能代表环氧树脂附近探针的区域。
产品规格
| Measurements Made | Soil electrical conductivity (EC), relative dielectric permittivity, volumetric water content (VWC), soil temperature |
| Required Equipment | Measurement system |
| Soil Suitability | Long rods with large sensing volume (> 6 L) are suitable for soils with low to moderate electrical conductivity. |
| Rods | Not replaceable |
| Sensors | Not interchangeable |
| Sensing Volume | 7800 cm3 (~7.5 cm radius around each probe rod and 4.5 cm beyond the end of the rods) |
| Electromagnetic |
CE compliant Meets EN61326 requirements for protection against electrostatic discharge and surge. |
| Operating Temperature Range | -50° to +70°C |
| Sensor Output | SDI-12; serial RS-232 |
| Warm-up Time | 3 s |
| Measurement Time | 3 ms to measure; 600 ms to complete SDI-12 command |
| Power Supply Requirements | 6 to 18 Vdc (Must be able to supply 45 mA @ 12 Vdc.) |
| Maximum Cable Length | 610 m (2000 ft) combined length for up to 25 sensors connected to the same data logger control port |
| Rod Spacing | 32 mm (1.3 in.) |
| Ingress Protection Rating | IP68 |
| Rod Diameter | 3.2 mm (0.13 in.) |
| Rod Length | 300 mm (11.8 in.) |
| Probe Head Dimensions | 85 x 63 x 18 mm (3.3 x 2.5 x 0.7 in.) |
| Cable Weight | 35 g per m (0.38 oz per ft) |
| Probe Weight | 280 g (9.9 oz) without cable |
Current Drain |
|
| Active (3 ms) |
|
| Quiescent | 135 µA typical (@ 12 Vdc) |
Electrical Conductivity |
|
| Range for Solution EC | 0 to 3 dS/m |
| Range for Bulk EC | 0 to 3 dS/m |
| Accuracy | ±(5% of reading + 0.05 dS/m) |
| Precision | 0.5% of BEC |
Relative Dielectric Permittivity |
|
| Range | 1 to 81 |
| Accuracy |
|
| Precision | < 0.02 |
Volumetric Water Content |
|
| Range | 0 to 100% (with M4 command) |
| Water Content Accuracy |
|
| Precision | < 0.05% |
Soil Temperature |
|
| Range | -50° to +70°C |
| Resolution | 0.001°C |
| Accuracy |
|
| Precision | ±0.02°C |
兼容性
Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.
数据采集器
| Product | Compatible | Note |
|---|---|---|
| CR1000X (retired) | ||
| CR300 (retired) | ||
| CR3000 (retired) | ||
| CR310 | ||
| CR350 | ||
| CR6 | ||
| CR800 (retired) | ||
| CR850 (retired) |
Additional Compatibility Information
射频考虑
外部的射频源
外部的射频源会影响探头的工作；因此，探头的位置应当远离明显的射频源，例如交流电线及电机。
探头间干扰
多个 CS650 传感器的相互之间的安装距离小于4 英寸，当使用标准的数据采集器 SDI-12 “M” 命令时。SDI-12 “M” 可以使得一次只激活一个探头。
安装工具
在密实或基岩性土壤中，使用 CS650G 工具会让安装CS650探头更容易。将CS650 敲入土壤中，钻出平行小孔（与CS650 探针间距一致），再将CS650 插入，可以最大可能避免损坏CS650传感器。
数据采集器考虑
可兼容的当代数据采集器
| CR200(X) 系列 | CR800/CR850 | CR1000 | CR3000 | CR7X | CR9000X | CR6 |
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Compatible Retired Dataloggers
| CR500 | CR510 | CR10 | CR10X | 21X | CR23X | CR5000 | CR9000 |
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下载
CS650 / CS655 Firmware v.2 (429 KB) 02-12-2015
Current CS650 and CS655 firmware.
Note: The Device Configuration Utility and A200 Sensor-to-PC Interface are required to upload the included firmware to the sensor.
常见问题解答
CS650: 50
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The cable properties and power requirements of the CS650 and the CS655 are such that communication with a data logger may work for cable lengths greater than 2,000 ft. If multiple sensors are communicating through the same universal or control terminal, the total length of all of those sensors must not exceed 2,000 ft.
In practice, it is less expensive to purchase a new data logger than to buy a CS650 or CS655 with 2,000 ft of cable. If the cable is run through conduit, or if a 2,000 ft long trench needs to be excavated, then the installation cost becomes more expensive than buying another data acquisition system and sensors with shorter cables.
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The CS650 and the CS655 are not ideal sensors for measuring water level. However, these sensors do respond to the abrupt change in permittivity at the air/water interface. A calibration could be performed to relate the period average or permittivity reading to the distance along the sensor rods where the air/water interface is located. From that, the water level can be determined. The permittivity of water is temperature dependent, so a temperature correction would be needed to acquire accurate results.
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The dielectric of water at room temperature is close to 80. The firmware for both the CS650 and the CS655 is programmed to change volumetric water content to NAN or 9999999 when the permittivity measurements are greater than 42. When testing in water, look at the permittivity reading rather than the water content reading. If a test is being done for functionality, pull the sensor about halfway out of the water to see both permittivity and volumetric water content readings.
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In soil that has a significant fraction of fines (loam, silt loam, silty clay loam, clay loam, clay), the CS655 is a suitable option because these soils tend to be more electrically conductive, and the CS655 operates over a larger range of electrical conductivity than the CS650. In applications where a smaller measurement volume is desired, such as larger greenhouse pots, the 12 cm long rods of the CS655 are preferable to the 30 cm long rods of the CS650.
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The volumetric water content reading is the average water content over the length of the sensor’s rods.
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CS650 and CS655 sensors are read one at a time using SDI-12 commands. Consequently, they are never active at the same time and do not interfere with each other electrically. When installing the sensors close together, a general guideline is to keep them at least 10 cm apart.
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Modifications to the CS650 or CS655, including shortening the cable, will void the warranty. However, shortening the cable will not affect the sensor’s performance. If a decision is made to shorten the cable, care should be taken to avoid damaging the cable jacket and exposing bare wire except at the ends that connect to the data logger or multiplexer terminals.
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The permittivity of saturated sediments in a stream bed is expected to read somewhere between 25 and 42, while the permittivity of water is close to 80. A CS650 or CS655 installed in saturated sediments could be used to monitor sediment erosion. If the permittivity continuously increases beyond the initial saturated reading, this is an indication that sediment around the sensor rods has eroded and been replaced with water. A calibration could be performed that relates permittivity to the depth of the rods still in the sediment.
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Period average and electrical conductivity readings were taken with several sensors in solutions of varying permittivity and varying electrical conductivity at constant temperature. Coefficients were determined for a best fit of the data. The equation is of the form
Ka(σ,τ) = C0*σ3*τ2 + C1*σ2*τ2 + C2*σ*τ2 + C3*τ2 + C4*σ3*τ + C5*σ2*τ + C6*σ*τ + C7*τ + C8*σ3 + C9*σ2 + C10*σ + C11
where Ka is apparent dielectric permittivity, σ is bulk electrical conductivity (dS/m), τ is period average (μS), and C1 to C11 are constants.
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No. The equation used to determine volumetric water content in the firmware for the CS650 and the CS655 is the Topp et al. (1980) equation, which works for a wide range of mineral soils but not for organic soils. In organic soils, the standard equations in the firmware will overestimate water content.
When using a CS650 or a CS655 in organic soil, it is best to perform a soil-specific calibration. For details on performing a soil-specific calibration, refer to “The Water Content Reflectometer Method for Measuring Volumetric Water Content” section in the CS650/CS655 manual. A linear or quadratic equation that relates period average to volumetric water content will work well.
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