Curve point tables

A curve point table can either be read in from an ASCII file or assigned within the user program. When importing from a file, make sure that the file has the following format:

  • The first line contains an integer n, which defines the number of curve point pairs.
  • This is followed by n lines in which the master position and slave position are separated by a tab.

It does not matter whether it is a text file (*.txt) or a CSV file (*.csv).

An example file Interpolation.txt could look like this:

The interpolation of a curve point table takes place in the context of a cam profile, i.e. within a cam profile, a segment is configured in such a way that it interpolates the given curve point table in the desired way (linear, cubic or spline).

The size of the curve point table for linear or cubic interpolation (data type ST_PointsList) is set to 1024 points. However, the user can vary the relevant constant "gc_uMaxNumberOfInterpPoints" via the library parameters. The largest value that can be set is 16383. However, it must be taken into account that the set value applies to all objects of type ST_PointsList used in the user program. In the event of a significant increase in size, it is therefore advisable to check whether the memory available in the MOVI-C® CONTROLLER is large enough to accommodate the compiled program code and all required data.

The size of the curve point table for spline interpolation (data type ST_PointsList-
Spline) is fixed to the maximum value of 64 and cannot be changed.

The interpolation of a curve point table is therefore realized in 3 steps:

  1. Assignment of the curve point table to a data type ST_PointsList or ST_PointsListSpline either by reading in a file or by assignment directly in the user program.
  2. Configuration of the desired interpolation mechanism in a cam description of type CamDescription.
  3. Processing of this cam description with an MC_CamIn function block.