CS65030 cm Soil Moisture and Temperature Sensor

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1. CS650可以测量海水和海冰的介电常数和电导率吗？

   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.

   关于海冰，随着水从液体变为固态，海水冻结和介电常数从大约88变为4的变化时，电导率显着下降。随着EC和介电常数均落到CS650测量范围内的水平，该传感器有望在海冰中给出有效的读数。传感器坚固，可以承受寒冷的温度。但是，随着冰的融化，将有一个点，使电导率变得太高，无法获得有效的读数以获得介电常数或电导率。

2. With the CS650 and the CS655, where is the electrical conductivity measurement made?

   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.

3. Can the CS650 and the CS655 measure water content in gravel?

   是的。在安装过程中，保持传感器杆在砾石中特别困难，但可以做到。砾石具有较大的孔隙空间，可快速排水，因此水含量读数可能会显示饱和度和非常干燥之间的快速变化。如果有趣的是在干端的水含量变化很小，则可能需要进行土壤特定的校准，以将平均定期平均转换为体积水含量。

4. Can the CS650 and the CS655 measure gasoline or other hydrocarbons in soil?

   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. Gasoline and other hydrocarbons have dielectric permittivities in the same range as soil particles, which essentially make them invisible to the CS650 and the CS655.

5. Can the CS650 and the CS655 measure water level?

   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.

6. Can the CS650 and the CS655 be calibrated by incremental insertion into saturated soil?

   否。空气和饱和土壤界面处的突然介电常数会导致平均响应不同，而当传感器杆完全插入土壤中时发现的渐进介电常数变化。

   For example, if a CS650 or a CS655 was inserted halfway into a saturated soil with a volumetric water content of 0.4, the sensor would provide a different period average and permittivity reading than if the probe was fully inserted into the same soil when it had a volumetric water content of 0.2.

7. How can it be determined if soil is out-of-bounds for a CS650 or a CS655?

   If information is available on soil texture, organic matter content, and electrical conductivity (EC) from soil surveys or lab testing of the soil, it should be possible to tell if the soil conditions fall outside the range of operation of the sensor. Without this information, an educated guess can be made based on soil texture, climate, and management:

   • Soil that is coarse textured (such as sand, loamy sand, or sandy loam) works well with a CS650 if the EC is low.
   • 如果土壤位于干旱或半干旱地区，则可能具有高EC。
   • If the soil is frequently fertilized or irrigated with water that has higher EC, it may have high EC.
   • 如果气候提供足够的降雨来冲洗根区域以下累积盐，则EC预计将是低且适合CS650的降雨。

   When in doubt about soil texture and electrical conductivity, Campbell Scientific recommends using a CS655 because of the sensor’s wider range of operation in electrically conductive soils, as compared with the CS650.

8. Do the CS650 and the CS655 have surge protection?

   是的。There is surge protection built into the sensor electronics. The sensor survives a surge of 2 kV at 42 ohm line-to-ground on digital I/O and 2 kV at 12 ohm line-to-ground on power. It also survives a surge of 2 kV at 2 ohm line-to-ground on the rods.

   If additional surge protection is required, consider using theSVP100Surge Voltage Protector DIN Rail with Mounting Hardware。

9. Can the CS650 and the CS655 be repaired?

   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.了解更多信息，参考Repair and Calibrationpage.

10. CS650和CS655有何不同？

    CS650棒,有30厘米长,和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.