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 | ||
| CR300 | ||
| 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: 54
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Campbell Scientific strongly discourages shortening the sensor’s rods. The electronics in the sensor head have been optimized to work with the 30 cm long rods. Shortening these rods will change the period average. Consequently, the equations in the firmware will become invalid and give inaccurate readings.
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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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The CS650 and CS655 are warranted by Campbell Scientific to be free from defects in materials and workmanship under normal use and service for 12 months from the date of shipment. For further details, see the “Warranty” section of the CS650/CS655 manual.
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No. The principle that makes these sensors work is that liquid water has a dielectric permittivity of close to 80, while soil solid particles have a dielectric permittivity of approximately 3 to 6. When liquid water freezes, its dielectric permittivity drops to 3.8, essentially making it look like soil particles to the sensor. A CS650 or CS655 installed in soil that freezes would show a rapid decline in its volumetric water content reading with corresponding temperature readings that are below 0°C. As the soil freezes down below the measurement range of the sensor, the water content values would stop changing and remain steady for as long as the soil remains frozen.
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A thermistor is encased in the epoxy head of the sensor next to one of the stainless-steel rods. This provides an accurate point measurement of temperature at the depth where that portion of the sensor head is in contact with the soil. This is why a horizontal placement is the recommended orientation of the CS650 or CS655. The temperature measurement is not averaged over the length of the sensor rods.
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Mine tailings are highly corrosive and have high electrical conductivity. Some customers have successfully used water content reflectometers, such as the CS650 or the CS655, to measure water content in mine tailings by coating the sensor rods with heat-shrink tubing. This affects the sensor output, and a soil-specific calibration must be performed. Care must be taken during installation to avoid damaging the heat-shrink tubing and exposing the sensor’s rods. In addition, covering the sensor’s rods invalidates the bulk electrical conductivity reading. Unless the temperature reading provided by the CS650 or the CS655 is necessary, a better option may be to use a CS616 with coated rods.
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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 CS650 has rods that are 30 cm long, and the CS655 has rods that are 12 cm long. The difference in rod length causes some changes in specifications. For example, the CS650 is slightly more accurate in its permittivity and water content readings, but the CS655 works over a larger range of electrical conductivity. In addition, the CS650 handles a larger measurement volume and provides good accuracy in low EC (electrical conductivity) sand and sandy loam. The CS655 is typically more accurate in soil, works well over a wide range of soil textures and EC, and is easier to install because of its shorter rods.
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The bulk electrical conductivity (EC) measurement is made along the sensor rods, and it is an average reading of EC over that distance at whatever depth the rods are placed.
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Because the reported volumetric water content reading is an average taken along the entire length of the rods, the sensor should be fully inserted into the soil. Otherwise, the reading will be the average of both the air and the soil, which will lead to an underestimation of water content. If the sensor rods are too long to go all the way into the soil, Campbell Scientific recommends inserting the rods at an angle until they are fully covered by soil.
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