Reference Manual Rev 3.23
Software Versions 3.xx
Page 44
8.2.2. DIR.SPN (Direct Span Calibration Entry)
Press the <OK> key to start. The display will show the current weight.
Press the <OK> key to enter the Direct Span setting. Change the mV/V setting to
the correct value for the full scale signal strength, using the <SEL> and <EDT>
keys.
Press the <OK> key to store the new span calibration. When the process is
complete the display will return to weight to allow the new weight reading to be
checked.
Press the <ITM> key to leave the Direct Span routine or <OK> to repeat the
operation.
8.3. Using Linearisation (K302 only)
This section provides instructions on the use of the linearisation. Linearisation is
used to approximate the weight output to a non-linear scale. The chart below shows
a non-linear characteristic for the load cell output. From the chart, it can be seen
that the trace with no linearisation applied is a poor approximation to the real
characteristic. By applying one or more linearisation points, more accurate weight
readings can be achieved.
0
500
1000
1500
2000
2500
3000
3500
0
2
4
6
8
10
Load Cell Output (mV)
W
e
ig
h
t (K
g
)
Actual Load Cell Characteristic
No Linearisation
Linearisation Applied
Span Point
Zero Point
Linearisation Point
Figure 18: Chart - Non-Linear Characteristic for Load Cell Output
To perform a linearisation, a calibration of the zero and full scale span points must
have been performed. Both the zero and full scale calibration points are used in the
linearisation of the scale base. These two points are assumed to be accurately set
and thus have no linearisation error.
A maximum of ten linearisation points can be set independently between zero and
full scale. Unused or unwanted points may also be cleared. The maximum
correction that can be applied using a linearisation point is + / - 2%.
