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Why Does Motion Assistant Exceed Velocity Constraints when Running a Contoured Move?

Primary Software: Motion Assistant
Primary Software Version: 2.0
Primary Software Fixed Version: N/A
Secondary Software: N/A

Problem:
I am running a contoured move in Motion Assistant, and when I use a Position Profile the velocity exceeds my maximum velocity specified in the Move Constraints tab. Why isn't Motion Assistant keeping motor velocity within the limits that I set?

Solution:
When the Motion Assistant runs a 1-D contouring step with a Position Profile contour parameter it does not take direction reversal into account.  If you specify contoured points that reverse the direction of the move, the velocity of the move will exceed the velocity constraints in order to meet the contour parameter.

Complete the following steps to view an example of this behavior:

1. Launch Motion Assistant.
2. Add a Contoured Move step.
3. Select 1D in the Configure tab.
4. Select the Contouring Parameters tab.
5. Select Tab Delimited Text in Type of input.
6. In File Name, navigate to <National Instruments>\Motion Assistant\Examples\Contouring \1D Contour.txt, where <National Instruments> represents the location where you installed Motion Assistant.



7. Run the script.

Refer to the Velocity View for an example of how the 1-D contoured move exceeds the velocity constraints that are specified in the script.  This behavior can be avoided by using a Position-Velocity-Time profile, as opposed to a Postion profile.

Related Links:
KnowledgeBase 4EEJKGQ7: Can I Specify Acceleration and Velocity for a Contoured Move?

Attachments:





Report Date: 04/09/2004
Last Updated: 06/03/2009
Document ID: 3889JV4I

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