Description

Function description

This procedure linearizes characteristic curves using interpolation. The procedure works with variable support point widths.

The number of X/Y_Coord_SupportPoint_n inputs can be increased from 2 to a maximum of 30 by vertically resizing the block frame. This corresponds to a maximum of 15 support points.

The number of inputs must be even.

The InputVariable values must be in ascending order.

and can be configured as additional parameters. It is recommended to use the ENO output parameter as an error indicator.

Representation in FBD

Representation:

Representation in LD

Representation:

Representation in IL

Representation:

LD InputVariable
LOOKUP_TABLE1 X_Coord_SupportPoint_1,
              Y_Coord_SupportPoint_1, OutputVariable,
              IndicatorX_GT_Xm, IndicatorX_LT_X1

Representation in ST

Representation:

LOOKUP_TABLE1 (InputVariable, X_Coord_SupportPoint_1,
               Y_Coord_SupportPoint_1, OutputVariable,
               IndicatorX_GT_Xm, IndicatorX_LT_X1);

Parameter description

Description of input parameters:

Parameter	Data type	Description
InputVariable	REAL	Input variable
X_Coord_SupportPoint_1	REAL	X coordinate 1. Support point
Y_Coord_SupportPoint_1	REAL	Y coordinate 1. Support point
X_Coord_SupportPoint_1(n-1)	REAL	X coordinate . Support point n=max 30
Y_Coord_SupportPoint_(n)	REAL	Y coordinate . Support point n=max 30

Description of output parameters:

Parameter	Data type	Description
OutputVariable	REAL	Output variable
IndicatorX_GT_Xm	BOOL	Display: X > Xm
IndicatorX_LT_X1	BOOL	Indicate X < X1

Runtime error

NOTE: For a list of all block error codes and values, see Tables of Error Codes for the CONT_CLC Library.

EN stands for ENable; it is an optional block input. When the EN input is enabled, an ENO output is set automatically.

If EN = 0, the block is not enabled; its internal program is not executed, and ENO is set to 0.

If EN = 1, the block's internal program is run and ENO is set to 1. If an error occurs, ENO is set to 0.

If the EN input is not connected, it is set automatically to 1.

REAL

The REAL type is encoded in a 32 bit format.

The possible value ranges are shown in the figure below:

When a result is:

between -1,175494e-38 and 1,175494e-38, it is considered to be a DEN;
less than -3.402824e+38, the symbol -INF (for - infinity) is displayed;
greater than +3.402824e+38, the symbol INF (for + infinity) is displayed;
undefined (square root of a negative number), the symbolNAN is displayed.

NOTE: The IEC 559 standard defines two classes of NAN: the silent NAN (QNAN) and the signaling NAN (SNAN). A QNAN is a NAN with a most significant fraction bit while an SNAN is a NAN without a most significant fraction bit (bit number 22). QNANs can be propagated via most arithmetic operations without throwing an exception. As for SNANs, they generally indicate n invalid operation when they are used as operands in arithmetic operations (see %SW17 and %S18).

NOTE: When a DEN (non-standardized number) is used as an operand, the result is not significant.