Campbell Scientific Sentek TriSCAN® Manual v 1.2a - Manual (Page 12)

TriSCAN Manual Version 1.2a
Copyright © 1991 – 2004 Sentek Pty Ltd All rights reserved Page 5
What is TriSCAN?
TriSCAN Features
TriSCAN is the world’s first near-continuous in-field monitoring probe to measure soil water content and soil
salinity throughout a soil profile. Soil water and salinity measurements are taken by the same sensor
successively. The TriSCAN technology is protected by various world patents.
Sensor and Probe
The sensor consists of a tubular housing with two conductive surfaces. The electronic circuit contained
within this housing connects into a ribbon cable running inside the extruded plastic support (probe rod)
which carries the sensors. The probe rod can be fitted with multiple sensors, located at 100 mm intervals
along its length. Each configuration of multiple sensors fitted to a probe rod constitutes a probe. A total of 16
TriSCAN sensors can be mounted to a probe at chosen depth intervals by the user.
Arrays of sensors can be typically installed to depths of 0.5 m, 1.0 m, 1.5 m, 2 m and 3 m. Special probe
lengths can be ordered and installed to greater than 3 m pending favourable installation conditions. The
TriSCAN technology is also offered as an EasyAG

probe version, where 4 smaller diameter sensors are
fixed on to a probe rod at depths of 100 mm, 200 mm, 300 mm and 500 mm.
Access Tubes
During installation, the probe is lowered into a specially extruded plastic tube inserted into the soil at the
desired measuring location. Readings of soil water content and soil salinity are taken through the plastic
access tube without any direct contact between the sensor and soil. The top and bottom of the access tube
is sealed to prevent the entry of water and moisture. The top cap of the access tube allows cable entry from
the probe to a suitable data logger through a water-tight grommet.
The TriSCAN EasyAG probes are lowered into the smaller diameter EasyAG access tube body.
Figure 1. Cut-away view of the TriSCAN probe
Probe Interface and Data Acquisition Systems
The TriSCAN can be fitted with two probe interfaces: SDI-12 and RS232/RS485 Modbus. This means that
data loggers supporting the SDI-12 or RS232/RS485 Modbus protocol can be used to connect and log soil
water and salinity data.