Campbell Scientific CS616 and CS625 Water Content Reflectometers - Manual (Page 7)

CS616 and CS625 Water Content
Reflectometers
1. Introduction
The CS616 Water Content Reflectometer is an improved version of the CS615
Water Content Reflectometer. The CS625 is a modified CS616 for use with
the Campbell Scientific CR200(X) series dataloggers. The difference between
the CS616 and the CS625 is the output voltage level.
Both water content reflectometers are designed to measure volumetric water
content of soils or other porous media. The water content information is
derived from the probe sensitivity to the dielectric constant of the medium
surrounding the probe rods.
Before installing the CS616 or CS625, please study
• Section 2, Cautionary Statements
• Section 3, Initial Inspection
2. Cautionary Statements
• Although the CS616/CS625 is rugged, it should be handled as precision
scientific instrument.
• External RF sources can affect CS616/CS625 measurements.
Consequently, the CS616/CS625 circuitry should be located away from
significant sources of RF such as ac power lines and motors.
• CS616/CS625 probes enabled simultaneously and within approximately 9
inches of each other can cause erratic measurements. If probes must be
close to each other, configure the enable lines to the datalogger control
ports so that the probes are not enabled simultaneously.
3. Initial Inspection
• Upon receipt of the CS616/CS625, 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 expected product and cable length are received.
4. Overview
The CS616 output is a square wave output and can be connected to our CR800,
CR850, CR1000, CR3000, CR5000, CR510, CR10X, and CR23X dataloggers.
A special CS616 datalogger instruction is used to measure the probe output
period which is converted to volumetric water content using calibration
equations. Datalogger instructions for period averaging can also be used.
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