CS650 时域反射土壤含水量传感器
创新的
在高容积电导率土壤中的精度更高
气象 应用支持 水资源 应用支持 能源 应用支持 湍流通量 应用支持 基础结构/工业设施 应用支持 土壤 应用支持

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)
  • 45 mA typical (@ 12 Vdc)
  • 80 mA (@ 6 Vdc)
  • 35 mA (@ 18 Vdc)
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
  • ±(2% of reading + 0.6) from 1 to 40 for solution EC ≤ 3 dS/m
  • ±1.4 (from 40 to 81 for solution EC ≤1 dS/m)
Precision < 0.02

Volumetric Water Content

Range 0 to 100% (with M4 command)
Water Content Accuracy
  • ±1% (with soil-specific calibration)
  • ±3% (typical with factory VWC model) where solution EC < 3 dS/m
Precision < 0.05%

Soil Temperature

Range -50° to +70°C
Resolution 0.001°C
Accuracy
  • ±0.1°C (for typical soil temperatures [0 to 40°C] when probe body is buried in soil)
  • ±0.5°C (for full temperature range)
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
21X (retired)
CR10 (retired)
CR1000X
CR10X (retired)
CR200X (retired)
CR206X (retired)
CR211X (retired)
CR216X (retired)
CR23X (retired)
CR295X (retired)
CR300
CR3000
CR310
CR500 (retired)
CR5000 (retired)
CR510 (retired)
CR6
CR800
CR850
CR9000 (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

Compatible Retired Dataloggers

CR500 CR510 CR10 CR10X 21X CR23X CR5000 CR9000

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.

查看修订历史

常见问题解答

CS650: 54

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  1. 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.

  2. 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. 

  3. The CS650-series sensors have the same rugged epoxy and stainless-steel rods that have been used for water content reflectometers since the CS615-L model was introduced in 1995. There are CS615-L and CS616 sensors in many locations that have been in continuous use for more than ten years with no reported problems. If a CS650 or CS655 remains undamaged by external forces such as lightning, harsh chemicals, or animal actions, the sensor is expected to continue working for decades. 

  4. Probably not. 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. Because the permittivity of water is over an order of magnitude higher than that of soil solids, water content has a significant impact on the overall bulk dielectric permittivity of the soil. When the soil becomes very dry, that impact is minimized, and it becomes difficult for the sensor to detect small amounts of water. In air dry soil, there is residual water that does not respond to an electric field in the same way as it does when there is enough water to flow among soil pores. Residual water content can range from approximately 0.03 in coarse soils to approximately 0.25 in clay. In the natural environment, water contents below 0.05 indicate that the soil is as dry as it is likely to get. Very small changes in water content will likely cause a change in the sensor period average and permittivity readings, but, to interpret those changes, a very careful calibration using temperature compensation would need to be performed.  

  5. The electrical conductivity (EC) of sea water is approximately 48 dS/m. The CS650 can measure permittivity in water with EC between 0 and 3 dS/m. EC readings become extremely unstable at conductivities higher than 3 dS/m and are reported as NAN or 9999999. Because EC is part of the permittivity equation, an EC reading of NAN leads to a permittivity reading of NAN as well. Thus, the CS650 cannot provide good readings in sea water.

    With regard to sea ice, the electrical conductivity drops significantly when sea water freezes and the permittivity changes from approximately 88 down to approximately 4, as the water changes from a liquid to a solid state. With both EC and permittivity falling to levels that are within the CS650 measurement range, the sensor is expected to give valid readings in sea ice. The sensor is rugged and can withstand the cold temperatures. However, as the ice melts, there will be a point at which the electrical conductivity becomes too high to acquire a valid reading for either permittivity or electrical conductivity.

  6. 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.  

  7. 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.  

  8. No. The temperature sensor is located inside the sensor’s epoxy head next to one of the sensor rods. The stainless-steel rods are not thermally conductive, so the reported soil temperature reading is actually the temperature of the sensor head. If the CS650 or the CS655 is installed horizontally, which is the preferred method, then the sensor head will be at the same temperature as the soil, and the soil temperature value will be accurate. However, if the sensor is installed vertically, and/or with the sensor head above ground, the soil temperature reading will be less accurate. Because the sensor orientation is not known, no temperature correction was written into the firmware.  

  9. Damage to the CS650 or the CS655 electronics or rods cannot be repaired because these components are potted in epoxy. Cable damage, on the other hand, may possibly be repaired. For more information, refer to the Repair and Calibration page.

  10. 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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