Loading an Contoured Move

[wade75]

Hello,

         I need to know if there is a way to load and execute a pre-defined Contoured Move, built using a sine wave generator, without using the Motion Assistant API's.  Only the Motion Control API's.  I have been using the evaluation version of the Motion Assistant to get an understanding of the NI Motion Control, however the free trial expired.  I need to know for sure if NI Motion is the correct path for my application.  Thanks.

Wade

[iZACHdx]

Hello,

The Motion Assistant makes it much easier to define and load a contoured move. The predefined countour is basically a text file with the data required to generate the move. Unfortunately, there is no express VI or anything like that to load the file and then execute it. You would have to programatically load the file and then generate the moves with the Motion APIs if you do not want to use the Motion Assistant anymore.

-Zach

[Jochen]

Wade,

the Smart Contouring feature of Motion Assistant makes contouring much easier, but also without Motion Assistant contouring is not rocket science. The most important thing is to understand the concept how the motion control board runs a contoured move.

In contouring mode you need to download an array of position data to the board. The motion control board steps through this list of positions at a fixed rate (10 or 20 ms - user selectable). E. g. this list results in a move with constant velocity:

...10, 20, 30, 40, 50...

If the update rate is set to 10 ms, the velocity of the resulting move is 1000 steps/sec.

In contrast this list results in move with constant acceleration:

...10, 20, 40, 70, 110, 160,...

Even though the timing of 10 or 20 ms seems to be a little bit coarse, contoured moves are typically very smooth, as the board interpolates between the setpoints from the position array with a cubic spline algorithm at the configured PID rate. Please refer to the contouring examples that ship with NI-Motion for further information.

Kind regards,

Jochen