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# Constant-Velocity : Specify Two Positions

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# Constant-Velocity : Specify Two Positions

### Constant-Velocity | Two Position

Motion-Description

 Use the Flexible-Polynomial to define a Two-Position Constant-Velocity The Velocity is calculated from the Segment-Width and the difference between the End-Position and Start-Positions. You must make sure the Velocity at the End of the Previous-Segment is equal to the velocity of this segment. The Acceleration and Jerk Values at the start and end of the segment are zero.

Motion-Values

You CAN specify the:

 Start-Position The Start-Position usually flows from the End-Position of the End-Position

You CANNOT specify the:

 Start-Velocity & End-Velocity Start-Acceleration & End-Acceleration Start-Jerk & End-Jerk

SEGMENT EDITOR: Control-Buttons for a 'Two Position | Constant-Velocity motion-law.

 1.Use the Motion-Law Selector to select a Flexible-Polynomial motion-law 2.Select the Segment and open the Segment Editor 3.De-select ALL Match (Flow) Control-Buttons 4.De-select Start-Velocity, Start-Acceleration, Start-Jerk Control-Buttons 5.De-select End-Velocity, End-Acceleration, End-Jerk Control-Buttons 6.Select the Start-Position and End Position Control-Buttons 7.Enter the Start-position and End-Position 8.Enter the correct X-axis values.

Note:

 When the Constant-Velocity segment is one segment of a complete machine-cycle use a Gearing FB, to replace a Motion FB  - assuming a Linear-Motion FB is connected to the input of the Gearing FB. When the Gearing-Ratio = 1 (in the Gearing dialog-box), the output will equal its input, it will increase steadily from 0 to 360. If you enter the equation 270/360 as the Gearing Ratio the output will be from 0 to 270, when its input is from 0 to 360. Thus, you can see it is easy to use a Gearing FB to output a Constant-Velocity for a complete a machine-cycle.