13
The meter has internal calibrations for standard
and high
-
clay soil types. It also has the option of
outputting a value that matches its predecessor, the
TDR 100. These calibrations will work for a large
number of soils. However, each meter will have a
small difference in how it responds to identical soil
conditions. This is due to sensor drift or variability
in the electronic components used during manufac-
turing. The meter allows for adjustments to the cal-
ibration to account for these differences. There-
fore, if two meters are giving slightly different
readings in the same soil, the output of the meters
can be standardized such that the meters can be
used interchangeably. After calibration, a TDR
150 in "TDR 300" mode (see p. 12) should read
the same as a TDR 300 meter.
To perform the calibration, you will need a 6" di-
ameter plastic container of distilled or de
-
ionized
water. The container must be at least as tall as the
length of the TDR rods. The procedure is as fol-
lows:
1.
From the Settings Menu (p. 11), scroll to the
Calibration option. Press the
Select
button to
initiate the calibration process.
2.
Hold the meter so the rods are in the air. Press
the
Menu/Select
button and wait until the me-
ter indicates it is ready.
3.
Immerse the rods completely in the water.
Press the
Menu/Select
button and wait until
the meter indicates it is ready.
Meter Calibration
