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10.9 Customized linearization
The user can create an individual linearization characteristic line for the analog input with the customer-specific lineari-
zation. Two procedures are available for this (type of linearization): formula or grid points (value pairs).
The text entered under „designation" is not used at another point in the setup program, but serves merely as text in
the sense of a brief description.
Formula
Linearization is specified using a formula with five coefficients (4th order polynomial).
Polynomial:
y = X4*x
+ X3*x
4
Parameter
Measuring range start
Measuring range end
X0
X1
X2
X3
X4
„Display graphic" button (displaying linearization on a graphic):
Use this button to create a graphic of the linearization.
The graphic includes the characteristic lines for both types of linearization where applicable, namely the formula and
the grid points (table).
The display range for the graphic is initially determined by the „measuring range start" and „measuring range end"
values (y values); it can be temporarily changed in the display by entering different x values.
Grid points
Linearization is specified by entering up to 40 grid points (pairs of values X,Y). The value X stands for the physically mea-
sured value (resistance in Ω or voltage in mV) for a RTD temperature probe or ther mocouple. With the other signal types,
the input variable is scaled to 0 to 100% (for voltage/current signal of measuring range, for resistance/potentiometer
of resistance Rx, for resistance transmitter of overall resistance). The value Y is the linearized value (e.g., temperature
in °C).
Parameter
Measured value (X)
Linearized value (Y)
button (calculating the polynomial using the grid points):
After entering the value pairs, use this button to calculate a polynomial that describes the progression of the lineariza-
tion characteristic line.
The calculated coefficients are incorporated into the formula. The characteristic lines for both types of linearization
then correspond to each other.
If the x values do not increase in a straight line, the linearization is not applied. In this case, it is impos sible to display
the graphic or calculate the polynomial.
Product:
Temperature controller XT-T1
+ X2*x
+ X1*x + X0
3
2
Selection/text/value
-1999 to 9999 (0)
-1999 to 9999 (100)
-1999 to 9999 (0)
-1999 to 9999 (0)
-1999 to 9999 (0)
-1999 to 9999 (0)
-1999 to 9999 (0)
Selection/text/value
-1999 to 9999 (0)
-1999 to 9999 (0)
Revision 2.0 – Issue September 2018
Description
Start value of the y axis (linearized value)
End value of the y axis (linearized value)
Absolute component of the polynomial (point of in-
tersection with the y axis)
Coefficient of the linear component (x)
Coefficient of the quadratic component (x
Coefficient of the cubic component (x
Coefficient of the quartic component (x
Description
Value of the relevant grid point on the x axis
Value of the relevant grid point on the y axis
E
)
2
)
3
4
)
147 /166
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