Calibration Consideration / Limits - AgraTronix 08150 Manual De Instrucciones

Operation

CALIBRATION CONSIDERATION / LIMITS

Typically the moisture tester will be consis-
tent with most elevator testers over a broad
range of moisture levels. However, there are
some things to consider when thinking about
your moisture tester calibration.
NOTE: Graph provided is for illustration
purposes only and does not refl ect actual
test data.
Tester Differences: Your moisture tester
unit, may not match a given elevator tester.
None of the testers exactly match the actual weighted moisture of any given
grain. There is no national standard for elevator testers. The difference between
moisture testers and various U.S.D.A. approved elevator testers is not a constant
value. A correction at one moisture level may not be valid for a different moisture
level. Graph 1 shows how the moisture tester might compare to an elevator tester
over a broad range of moisture levels. The moisture tester, and most elevator
testers (shown in graph by solid line) will closely match those of the moisture
tester (shown by dashed line) for that range, as illustrated. However, as we get
away from mid-range into the high and low moisture levels, differences between
elevator tester and moisture tester not only become greater, but may switch from
a moisture tester reading higher than elevator tester to a reading lower than the
elevator tester. For example, in Graph 1, the area between B and C represents
the mid-range moisture. Moisture tester readings match elevator tester readings
in this area with an accuracy of plus or minus 0.5 percent. The area between A
and B represents the low moisture range. Moisture tester readings differ more
from elevator tester readings, and are LOWER than elevator tester readings. The
area between C and D represents the high moisture range. Moisture tester read-
ings again differ more from elevator tester readings than they did at mid-range
moistures, but now the readings are HIGHER than elevator tester readings.
Calibration Requirements: Graph 1 illustrates that moisture tester readings
closely match elevator tester readings for mid-range moisture levels. (Graph is
for illustration purposes only and does not refl ect actual test data.) Calibration
changes required for grain in this moisture range will be small, if any. However,
if grain is very dry (Low Moisture Range) or very wet (High Moisture Range), it
may be necessary to calibrate your moisture tester unit against the elevator tes-
ter using a sample of your grain in both testers. Record the calibration correc-
tion required. It will be valid for all testing in that moisture range for that grain.
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