CS655.12厘米土壤水分和温度传感器

Expand AllCollapse All

1. CS650和CS655可以测量土壤中的汽油或其他碳氢化合物吗？

   不可以。使得这些传感器工作的原理是液态水的介电常数接近80，而土壤固体颗粒的介电介电常数约为3至6.汽油和其他烃在与土壤颗粒相同的范围内具有相同的介电常数，这基本上使它们不可见CS650和CS655。

2. Can the CS655 rods be shortened?

   Campbell Scientific strongly discourages shortening the sensor’s rods. The electronics in the sensor head have been optimized to work with the 12 cm long rods. Shortening these rods will change the period average. Consequently, the equations in the firmware will become invalid and give inaccurate readings.

3. CS650或CS655的电缆可以缩短吗？

   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.

4. Can the CS650 and the CS655 detect stream bed erosion?

   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.

5. CS650和CS655可以测量水位吗？

   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 CS655 measure permittivity and electrical conductivity of sea water and sea ice?

   海水的电导率（EC）约为48ds / m。CS655可以使用EC在0到8 DS / m之间测量水中的介电常数。EC读数在高于8ds / m的电导率方面变得极其不稳定，并且报告为NaN或9999999.由于EC是介电常数方程的一部分，因此NaN的EC读数导致NaN的介电常数读数。因此，CS655不能在海水中提供良好的读数。

   对海冰,电气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 CS655 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.

7. CS650和CS655可以通过增量插入饱和土壤校准吗？

   No. The abrupt permittivity change at the interface of air and saturated soil causes a different period average response than would occur with the more gradual permittivity change found when the sensor rods are completely inserted in the soil.

   例如，如果将CS650或CS655插入具有0.4的体积含水量0.4的体积含水量的饱和土中，则传感器将提供不同的时期平均水平和介质读数，而是当探针完全插入相同的土壤时体积含水量为0.2。

8. CS650和CS655可以测量温室盆中的水含量吗？

   Yes, but the pots would have to be large. The CS650 and CS655 can detect water as far away as 10 cm (4 in.) from the rods. If the pot has a diameter smaller than 20 cm (8 in.), the sensor could potentially detect the air around the pot, which would underestimate the water content. In addition, potting soil is typically high in organic matter and clay, causing the probable need for a soil-specific calibration.

9. CS650和CS655可以在砾石中测量水含量吗？

   Yes. Keeping the sensor rods parallel during installation is especially difficult in gravel, but it can be done. Gravel has large pore spaces that drain quickly, so the water content readings will likely show rapid changes between saturation and very dry. If small changes of water content at the dry end are of interest, a soil-specific calibration may need to be performed to convert period average directly to volumetric water content.

10. With regard to the CS650 and the CS655, is there a generic calibration equation for artificial soil?

    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 necessarily for artificial soils that typically have high organic matter content and high clay content. In this type of soil, the standard equations in the firmware will overestimate water content.

    在人造土壤中使用CS650或CS655时，最好执行土壤特定的校准。For details on performing a soil-specific calibration,请参阅“用于测量体积含水量的水含量反射仪方法”部分CS650/CS655 manual. A linear or quadratic equation that relates period average to volumetric water content will work well.