The 227 determines soil water potential by measuring electrical resistance. When the 227 is wet, electrical resistance is low. As the 227 dries, resistance increases.
The 227 cylindrical block is composed of gypsum cast around two concentric electrodes, which confine current flow to the interior of the block, greatly reducing potential ground loops. Gypsum located between the outer electrode and the soil creates a buffer against salts that may affect the electrical conductivity.
Campbell Scientific recommends removing the 227 during winter.
|Measurement Range||-10 to -1000 kPa|
|Calibration||Individual calibrations are required for accurate measurements. Refer to the sensor manual for more information.|
|Operating Temperature||Soil temperatures above freezing|
|Life Expectancy||Two freeze-thaw cycles|
|Electrode Description||Concentric cylinders|
|Cylinder Diameter||~2.25 cm (0.88 in.)|
|Cylinder Length||~2.86 cm (1.25 in.)|
|Weight||180 g (0.4 lb)|
Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.
Two single-ended channels and one excitation channel per probe are required.
Number of FAQs related to 227-L: 3
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Not every sensor has different cable termination options. The options available for a particular sensor can be checked by looking in two places in the Ordering information area of the sensor product page:
If a sensor is offered in an –ET, –ETM, –LC, –LQ, or –QD version, that option’s availability is reflected in the sensor model number. For example, the 034B is offered as the 034B-ET, 034B-ETM, 034B-LC, 034B-LQ, and 034B-QD.
All of the other cable termination options, if available, are listed on the Ordering information area of the sensor product page under “Cable Termination Options.” For example, the 034B-L Wind Set is offered with the –CWS, –PT, and –PW options, as shown in the Ordering information area of the 034B-L product page.
Note: As newer products are added to our inventory, typically, we will list multiple cable termination options under a single sensor model rather than creating multiple model numbers. For example, the HC2S3-L has a –C cable termination option for connecting it to a CS110 instead of offering an HC2S3-LC model.
Most Campbell Scientific sensors are available as an –L, which indicates a user-specified cable length. If a sensor is listed as an –LX model (where “X” is some other character), that sensor’s cable has a user-specified length, but it terminates with a specific connector for a unique system:
If a sensor does not have an –L or other –LX designation after the main model number, the sensor has a set cable length. The cable length is listed at the end of the Description field in the product’s Ordering information. For example, the 034B-ET model has a description of “Met One Wind Set for ET Station, 67 inch Cable.” Products with a set cable length terminate, as a default, with pigtails.
If a cable terminates with a special connector for a unique system, the end of the model number designates which system. For example, the 034B-ET model designates the sensor as a 034B for an ET107 system.
Many Campbell Scientific sensors are available with different cable termination options. These options include the following:
Note: The availability of cable termination options varies by sensor. For example, sensors may have none, two, or several options to choose from. If a desired option is not listed for a specific sensor, contact Campbell Scientific for assistance.