SurfLin

 Function Block - Linear interpolation on a surface.

Inputs

Input	Data Type	Range	Unit	Default	Description
X	REAL				X coordinate of the point to be interpolated.
XAxis	REAL[ ]				X coordinates of the known points of the X axis.
Y	REAL				Y coordinate of the point to be interpolated.
YAxis	REAL[ ]				Y coordinates of the known points of the Y axis.
ZVal	REAL[ ]				Z coordinate of the points defined by the axis.

Outputs

Output	Data Type	Range	Unit	Description
ERR	DINT			Error code if failed. 0 (zero) if OK.
OK	BOOL			TRUE if successful.
Z	REAL			Interpolated Z value corresponding to the X,Y input point.

Remarks

This function performs linear surface interpolation in between a list of points defined in XAxis and YAxis single dimension arrays.

• The output Z value is an interpolation of the Z values of the four rounding points defined in the axis.
  • Z values of defined points are passed in the ZVal matrix (two dimension array).
  • ZVal dimensions must be understood as: ZVal [ iX , iY ]
• Values in X and Y axis must be sorted from the smallest to the biggest.
  • There must be at least two points defined in each axis.
  • ZVal must fit the dimension of XAxis and YAxis arrays.
    • For instance:
      • XAxis : ARRAY [0..2] of REAL;
      • YAxis : ARRAY [0.3] of REAL;
      • ZVal : ARRAY [0..2,0..3] of REAL;
• If the input point is outside the rectangle defined by XAxis and YAxis limits, the Z output is bound to the corresponding value and an error is reported.

If the function fails, the ERR output gives the cause of the error:

Error Code	Meaning
0	OK
1	Invalid dimension of input arrays.
2	Invalid points for the X axis.
3	Invalid points for the Y axis.
4	X,Y point is out of the defined axis.

FBD Language Example

Not available.

FFLD Language Example

Not available.

IL Language Example

Not available.

ST Language Example

Not available.