10
The meter has internal calibrations for standard and
high
-
clay soil types. 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 manufacturing.
Meters with
firmware v. 6.5 or greater
allow for adjust-
ments to the meter calibration to account for these dif-
ferences. Therefore, 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. Because the meter output is par-
tially governed by rod length, the calibration should not
be done with rods that are significantly reduces in size
because of wear. The calibration procedure is as fol-
lows:
1. Use the MODE button to put meter in Calibration
mode (see p. 8). Hit the READ button
2. Hold the meter so the rods are in the air. Press the
READ button and wait until the meter indicates it is
ready.
3. Immerse the rods completely in distilled or de
-
ionized water. The container should have a minimum
diameter of 3 inches. Press the READ button and wait
until the meter indicates it is ready.
The meter will then show that the calibration is com-
plete for that specific rod length. If more than one rod
size is being used, a calibration operation must be done
for each one.
Note: This procedure is different than a soil
-
specific
calibration (Appendix 2, p. 28) where a unique calibra-
tion curve is generated.
Meter Calibration
