1710
‐
PT060PNE
Rev.
0
Page
38
of
57
5.5 Calibration
5.5.1
Theoretical calibration procedure
In
general,
the
best
calibration
method
consists
in
applying
a
known
weight
(sample
weight)
on
the
weighing
system.
This
method
is
not
always
possible
to
execute,
when
weights
boasting
a
too
high
mass
are
used.
Other
systems
implemented,
in
case
of
large
size
tanks,
consist
of:
use
of
tested
litre
counters
or
filling
with
a
specific
water
quantity.
In
case
of
tanks
of
large
capacity,
when
sufficient
calibration
weights
are
not
available
or
geometries
do
not
allow
loading
large
masses,
calibration
is
carried
with
substitute
weights:
1.
The
tank
is
loaded
with
known
weight
masses
2.
The
value
read
by
the
indicator
is
recorded
3.
The
known
weights
are
removed
4.
The
tank
is
loaded
with
the
material
(or
water,
or
material
used
by
the
system)
until
reaching
the
weight
value
indicated
in
point
1
5.
Re
‐
load
the
same
weights
previously
loaded
in
point
1
6.
The
value
read
by
the
indicator
is
recorded
7.
The
known
weights
are
removed
once
again
8.
The
tank
is
loaded
with
the
material
until
reaching
the
weight
value
indicated
in
point
3
9.
Repeat
steps
1
and
2
until
reaching
the
nominal
load,
then
correct
the
calibration
curve
(SPAN)
if
needed.
During
the
calibration
phase,
by
using
known
masses,
it
is
possible
to
check
the
interferences
and
errors
caused
by
the
application
of
the
load
on
mechanical
parts
or
load
cells.
After
carrying
out
the
configuration
steps
of
the
THEORETICAL
calibration
(setting
of
the
nominal
capacity
of
the
load
cells
system
and
relative
sensitivity),
it
is
a
good
practice
to
check
the
system’s
calibration.
Calibration
consists
of
the
following
steps:
Tare
with
permanent
storage
Calibration
of
the
zero
value
Calibration
of
full
scale
Linearization
Zero
and
full
scale
calibrations
define
the
instrument’s
calibration
curve.
OFFS 1
Permanent
tare.
This
function
allows
calibrating
and
storing
the
reset
value
in
a
non
‐
volatile
memory,
differently
from
the
value
reset
through
input,
which
is
lost
when
the
equipment
is
turned
off.
Resetting
does
not
alter
the
slope
of
the
calibration
curve.
2ERO 1
Zero
calibration
SPAN 1
Full
scale
calibration
LIN 1-2-3-4
Linearization
