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Scaling & Mapping Express VI does not interpolate correctly between specified data points.

Primary Software: LabVIEW Development Systems>>LabVIEW Full Development System
Primary Software Version: 7.0
Primary Software Fixed Version: N/A
Secondary Software: LabVIEW Development Systems>>LabVIEW Professional Development System

Problem: After defining the data table (Interpolate data table) within the configuration of the Scaling & Mapping Express VI : The output y values, only return the max and min threshold values in the table and not any of the points specified in between, as the input values change throughout the whole range of x min and x max.

Solution: This is because the data values in x are placed in descending order rather than in ascending order. The VI requires the data in x, to be placed in ascending order.

The Scalling and Mapping Express VI only works if the x values are placed in ascending order. Therefore by manipulating the data tables x and y values to ensure the x values are in ascending order the VI works correctly and interpolates between all the defined points and not just the max and min values for the x values.

Manipulation of the data table if your data is in the incorrect format can be done either manually using an ASCII editor such as Notepad or using Excel if you data table is very large.

Using Excel
  1. Open the file in Excel and select the data you need to sort using the mouse and holding the left mouse button down whilst moving over the data.

  2. Select the menu option Data->Sort and select Ascending to sort the data in the X column.

  3. You may then need to sort the Y data column using the same method in 2 in to either Ascending or Descending order.


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Report Date: 08/19/2004
Last Updated: 08/20/2004
Document ID: 3CI2RMGP

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