HBM WE2108 Serie Referenzhandbuch Seite 86

86
The following values apply in the illustrated example:
The following commands serve for setting the user characteristic through the inter-
face:
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There are two types of calibration depending upon the behaviour of the scale construction:
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Overview: Calibration by interface
Remarks:
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HBM
Designation
Characteristic point 1 display
Internal value without load
Internal characteristic point 1 value
CAP
LDW
LWT
LVA
LGC
Calibration of the scale at two points of the characteristic. The display changes propor-
tionally to the input signal between these values.
If in two−point calibration too large measured value deviations occur at medium loads, a
linearized characteristic with three or four points can be entered. A linearity error with a
turning point (positive and negative deviations from the straight line) can be corrected
with the aid of a 3rd order polynomial.
Calibration points
Calibration method
Characteristic
Partial load calibration
Commands
If the unit should be linearized, the total user characteristic is entered with the LVA com-
mands. No calibration with the LDW / LWT commands is required previously.
A possibly performed calibration with LDW / LWT is overwritten by the LVA (1..7) com-
mands.
If a LDW / LWT calibration is performed anew after linearization, then the linearization
points are deleted and LVA0 set to 0 (proportional function without linearization).
The entry with the LVA commands serves for the configuration of linearized scales refer-
enced to known values. Earlier values which were inadvertently deleted can also be
restored.
Automatic measurement of the internal values is possible only with the commands LDW /
LWT. The measured values must be determined initially in mV/V for calibrating with cali-
bration weights and with linearization.
Value in the example
6000
020000 (0.2 mV/V)
140000 (1.4 mV/V)
2 2
Measuring with Enter values
calibration weights
linear linear
yes (with com- yes
mand LVA2)
LDW, LWT, (LVA2) LVA0...3
Scale electronic unit (NSW)
Parameter name (see below)
LVA 2
LVA 1
LVA 3
3 4
Werte eingeben Werte eingeben
2nd order poly- 3rd order polyno-
nomial mial
no no
LVA0...5 LVA0...7
WE2108