COFFEE PRO MOISTURE-MAC - Calibration Consideration; Limits

Operation
1
0
C
ALIBRATION CONSIDERATION / LIMITS
T
ypically the moisture tester will be consistent
w
ith most elevator testers over a broad ran
g
e of
moisture levels. However, there are some things
to cons
id
er w
h
en t
hi
n
ki
ng a
b
out
y
our mo
i
sture
tester calibration.
N
OTE
:
G
raph provided is for illustratio
n
purposes only and does not re
fl
ec
t
a
ctual test data.
Tes
t
e
r Diff
e
r
e
n
ces
: Your moisture tester unit
,
ma
y
not match a given elevator tester. None of
the testers exactly match the actual weighted
moisture of an
y
given grain. There is no national standard for elevator testers. The
difference between moisture testers and various U.S.D.A. a
pp
roved elevator testers
i
s not a constant value. A correction at one moisture level ma
y
not be valid for a
different moisture level. Graph 1 shows how the moisture tester mi
g
ht 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 o
f
the
moisture tester
(
shown by dashed line
)
for that range, as illustrated. However, as we
get away
f
rom mid-range into the high and low moisture levels, di
ff
erences between
elevator tester and moisture tester not onl
y
become greater, but ma
y
switch from a
moisture tester readin
g
hi
g
her than elevator tester to a readin
g
lower than the elev
a
-
tor tester. For example, in
G
raph 1, the area between B and
C
represents the mid
-
ran
g
e moisture. Moisture tester readin
g
s match elevator tester readin
g
s in this area
with an accurac
y
of plus or minus 0.5 percent. The area between A and B represents
the low moisture ran
g
e. Moisture tester readin
g
s di
ff
er more
f
rom elevator tester
readings, and are LOWER than elevator tester readings. The area beween C and D
represents the hi
g
h moisture ran
g
e. Moisture tester readin
g
s a
g
ain di
ff
er more
f
rom
elevator tester readings than the
y
did at mid-range moistures, but now the readings
are HIGHER than elevator tester readin
g
s.
C
alibration Re
q
uirements
:
Graph 1 illustrates that moisture tester readings closely
match elevator tester readings for mid-range moisture levels.
(
Graph is for illu
s
-
t
ration purposes only and does not re
fl
ect actual test data.
)
Calibration chan
g
es
required for grain in this moisture range will be small, if an
y
. However, if grain is ver
y
d
ry
(L
ow
M
o
i
sture
R
ange
)
or very wet
(Hi
g
h
M
o
i
sture
R
ange
)
,
i
t may
b
e necessary
to calibrate
y
our moisture tester unit against the elevator tester using a sample of
y
our grain in both testers. Record the calibration correction required. It will be valid
f
or all testing in that moisture range for that grain.