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Name
Reserve 3
REAL
Reserve 4
BYTE
Reserve 5
BYTE
Table 5-1
DR3 Allocation
5.2.1
DR3 - Adjustment digits 0, 1, 2, 3, 4, for the zero point and Adjustment
weights 1, 2, 3, 4
The analog measurement value coming from the load cells is converted into a
digital value with an analog-digital converter. A weight value is then calculated from
this digital value. All functions of the SIWAREX FTA then use this weight value for
performing their tasks.
To calculate the weight value from the digital value, the characteristic curve of the
measurement system must be determined. In the simplest case, the characteristic
curve is defined through points 0 and 1. The first operating point (point 0) is always
determined by the empty scale alone with its own construction weight. The weight
of its own construction, the scale load cells deliver a measurement voltage to the
SIWAREX FTA. After the analog-digital conversion of the measurement voltage,
the digital value (adjustment digit 0) is assigned the zero point.
If the scale is loaded with a known calibration weight (e.g. with 50 % of the
measurement range), then the second operation point can be determined. The new
digital value from the digital-digital converter is now assigned with the calibration
weight.
The characteristic curve can be further adjusted using a maximum of three other
points that must lie above point 1.
Ensure that the difference between two adjustment weights is at least 5% of the
measurement range (= sum of the nominal loads of all load cells).
The adjustment consists of the following steps:
Define adjustment weights and other parameters of the DR 3 data record.
Preset all adjustment digits with 0
Send DR 3 to the scale
Give the instruction "Valid adjustment weight = 0"
Load the scale with the defined calibration weight
Give the instruction "Valid adjustment weight = 1"
Receive the DR 3 from the scale
Store the data to memory (disk)
The adjustment sequence for the increasing adjustment weight must be retained.
SIWAREX FTA
Type
Address
Default
DBD156
0
DBB160
0
DBB162
0
162
Range of Values / Explanation
Reserve 3
Reserve 4
Reserve 5
Weighing Functions
Re-
ference
5-45
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