Campbell Scientific 253-L and 257-L (Watermark 200) Soil Matric Potential Sensors - Manual (Page 7)

253-L and 257-L Soil Matric Potential
Sensors
1. Introduction
The 253 and 257 soil matric potential sensors are solid-state, electrical-
resistance sensing devices with a granular matrix that estimate soil water
potential between 0 and –2 bars (typically wetter or irrigated soils).
The 253 needs to be connected to an AM16/32-series multiplexer, and is
intended for applications where a larger number of sensors will be monitored.
The 257 connects directly to our dataloggers.
Before using a 253 or 257, please study:
• Section 2, Cautionary Statements
• Section 3, Initial Inspection
• Section 4, Quickstart
2. Cautionary Statements
• The black outer jacket of the cable is Santoprene
®
rubber. This jacket will
support combustion in air. It is rated as slow burning when tested
according to U.L. 94 H.B. and will pass FMVSS302. Local fire codes
may preclude its use inside buildings.
• Avoid installing in depressions where water will puddle after a rain storm.
• Don’t place the 253 or 257 in high spots or near changes in slope unless
wanting to measure the variability created by such differences.
• When removing the sensor prior to harvest of annual crops, do so just after
the last irrigation when the soil is moist.
• When removing a sensor, do not pull the sensor out by its wires.
• Careful removal prevents sensor and membrane damage.
3. Initial Inspection
• Upon receipt of a 253 or 257, inspect the packaging and contents for
damage. File damage claims with the shipping company.
• The model number and cable length are printed on a label at the
connection end of the cable. Check this information against the shipping
documents to ensure the correct product and cable length are received.
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