Reference Guide

PMAC Quick Reference Guide

Motion Programs 55

6. If the vector method of locating the arc center is used, the vector is specified by its I, J, and K

components (I specifies the component parallel to the X axis, J to the Y axis, and K to the Z axis).

This vector can be specified as a distance from the starting point (i.e. incrementally), or from the

XYZ origin (i.e. absolutely). The choice is made by specifying R in an ABS or INC statement (e.g.

ABS (R) or INC (R)). This affects I, J, and K specifiers together. (ABS and INC without

arguments affect all axes, but leave the vectors unchanged). The default is for incremental vector

specification.

7. PMAC’s convention is to take the short arc path if the R value is positive and the long arc path if R is

negative:

• If the value of R is positive, the arc to the move endpoint is the short route (<=180 degrees)

• If the value of R is negative, the arc to the move endpoint is the long route (>=180 degrees)

8. When performing a circular interpolation, the individual axes describe a position Vs time profile close

to a sine and cosine shape. This is true also for their velocity and acceleration profiles. Therefore,

circular interpolation makes an ideal feature to described trigonometric profiles. Further, the period

(and so frequency) of the sine or cosine waves can be set by the total move time given by TA+TM.

delete gather

undefine all

#2->2000Y ;X is phantom

open prog1 clear

inc

inc (r)

ta300

ts0

tm1000 ;TA+TM is period

i13=10

normal k-1 ;X-Y plane

circle1 ;clockwise

x0 y0 i10 ;complete circle

&1b1r