5TE Operator’s Manual
6. Installing the Probes
22
Multiple Probe Installation
‘The 5TE sensor makes eletrical conductivity (EC) measure-
ments by exciting one screw on the sensor and measuring the
current that moves from that screw to the adjacent screw that
is grounded. The distance between the screws is an important
part of the EC calculation. If 5TE sensors are placed close
together (within 20cm), it is possible for some of the current
that leaves the excited screw to pass through the nearby sen-
sor’s ground screw, thus producing an erroneous sensor read-
ing.
This problem occurs regardless of what logging system you
are using if the ground wires are connected at all times. If you
must have your sensors close together, (i.e. column experi-
ments, etc) consider a multiplexing option that would isolate
the ground wires.
If you are installing sensors vertically at short depth intervals,
do not bury them directly over the top of each other.
Although at times the vertical distance may be less than 20cm,
the sensors can be staggered horizontally so they are not
directly above each other, thus meeting the distance require-
ment.
