For many studies of soil hydraulic properties, frequent measurement of positive or negative pressures is essential. This is most easily accomplished with pressure transducers. SMS caries pressure transducers that have been found to work well for soils studies in the laboratory or in the field.

The SMS pressure transducers work well with Campbell Scientific (www.campbellsci.com) data loggers, which provide constant excitation voltages of 2.5 or 5 volts. However, other data loggers may be used provided the data loggers can supply a constant excitation voltage of between 2.5 and 15 volts to one or more pressure transducers.

The most commonly used transducers have pressure ranges of + 1 psi (69 cm H2O), or + 15 psi (1 bar). The 1 psi transducer is most suitable for the tension infiltrometer and the Mariotte tube. The 15 psi transducer is generally used for tensiometers.