ADLINK PCI-8164 - Manual (Page 94)

82 Operation Theory
4.1.6 Circular interpolation for 2 axes
Any 2 of the 4 axes of the card can perform circular interpolation.
In the example below, circular interpolation means XY (if axes 0, 1
are selected and assigned to be X, Y respectively) axes simulta-
neously start from initial point, (0,0) and stop at end
point,(1800,600). The path between them is an arc, and the Max-
Vel is the tangential speed. Notice that if the end point of arc is not
at a proper position, it will move circularly without stopping.
Example
_8164_start_a_arc_xy(0 /*card No*/, 1000,0 /*center X*/, 0 /*cen-
ter Y*/, 1800.0 /* End X */, 600.0 /*End Y */ ,1000.0 /* MaxVel */)
To specify a circular interpolation path, the following parameters
must be clearly defined:
Center point: The coordinate of the center of arc (In absolute mode)
or the off_set distance to the center of arc (In relative
mode)
End point: The coordinate of end point of arc (In absolute mode)
or the off_set distance to center of arc (In relative
mode)
Direction: The moving direction, either CW or CCW.
It is not necessary to set radius or angle of arc, since the informa-
tion above gives enough constrains. The arc motion is stopped
when either of the two axes reached end point.
There are two groups of functions that provide 2-axis circular inter-
polation. The first group divides the four axes into XY (axis 0 and