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User manual SCAIME:
NU-Soft-eNod4F-E-0716_235704-C.doc
11.2
Calibration methods
Measurement scaling can be defined using one of the two following methods:
•
Theoretical calibration
involving the sensitivity of the sensor and a user-defined corresponding
capacity
•
Physical calibration
involving 1, 2 or 3 know loads (for a load cell)
Both can be achieved thanks to the functional commands.
11.3
Settings description
11.3.1
Maximum capacity
The
‘maximum capacity’
stands for the maximum sensor/load cell signal range. When the absolute value of the gross
measurement exceeds its value plus 9 divisions, the b
3
bit (positive overloading) or the b
2
bit (negative overloading) of
the measurement status is set to 1 (it can activate a logical output if it is assigned to the
‘defective measurement’
function).
The zero acquisition (on request or at power-up) is done only if the gross measurement value is contained between a
±10% range of the
‘maximum capacity’
(±2% if the
legal for trade
option is active).
The
‘maximum capacity’
setting also allows calibrating
eNod4
in case of a theoretical calibration in association with
the sensor sensitivity. Measurement scaling will be automatically adapted so as to deliver a gross measurement value
equivalent to the
‘maximum capacity’
for an analog signal corresponding to the sensor sensitivity.
After a theoretical calibration, the maximum capacity can be changed to fit to the application.
Admitted values : from 1 up to 10000000.
11.3.2
Number of calibration segments
The
‘number of calibration segments’
defines how many calibration segments are used during the physical calibration
procedure. Linear installations only need one segment.
Admitted values : from 1 up to 3.
11.3.3
Calibration loads 1/2/3
Before starting a physical calibration procedure, each calibration segment must be given a corresponding user value
(for example, 1000 points for a 1 kg load).
Admitted values : from 1 up to 10000000.
11.3.4
Sensor sensitivity
The
‘sensor sensitivity’
setting is used to achieve a theoretical calibration. The stored value for this parameter is the
load cell sensitivity in
mV/V
.
The user can adapt the value delivered by
eNod4
for the associated signal using the
‘maximum capacity’
and the
‘sensor sensitivity’
.
This setting is expressed with a 10
-5
factor (197500 is equivalent to a 1.975 mV/V load cell sensitivity or a 1.975 V input
voltage).
Admitted values : from 1 up to 1000000.
11.3.5
Scale interval
The
‘scale interval’
is the minimal difference between two consecutive indicated values (either gross or net).
Modification of scale interval is taking into account after a new calibration.
Admitted values : 1/2/5/10/20/50/100
11.3.6
Zero calibration
Zero calibration value corresponds to the A/D converter points measured during the ‘
zero acquisition
’ step of
a
physical calibration.
For a theoretical calibration this value must be set. It can be set automatically with the ‘
zero adjustment
’ command.
Note:
To be applied, any modification of this setting must be followed by an EEPROM back up and device reboots
(hardware or software).
Admitted values : from 0 up to +-10000000
11.3.7
Span coefficients 1/2/3
These coefficients are computed and written during calibration process. Writing these coefficients could be done if
you want to restore a previous calibration.
Note:
To be applied, any modification of this setting must be followed by an EEPROM back up and device reboots
(hardware or software).
Admitted values : different from 0.
