User manual
PMAC User Manual
178 Writing Programs for PMAC
Radius Size Specification
If the radius method of locating the arc center is used, the radius is the number after the letter R in the
move command. This value always represents the distance from the move starting point. With radius
specification, it is also necessary to specify whether the arc to the move endpoint is the long route (>=180
degrees) or the short route (<=180 degrees). The PMAC convention is to take the short arc path if the R
value is positive, and the long arc path if R is negative. R values are not modal. A value must be
specified on each move command line. It is not possible to do a full circle in a single move command
with a radius specification; the circle must be broken into at least two parts. A typical circular move
command with a radius specification is:
X1000 Y2000 R750
Example:
To do the same moves as in the above example, except with radius center specification, the program
would be:
NORMAL K-1 ; XY plane
F10
CIRCLE1
X20 Y20 R20 ; Arc move < 180 deg
X40 Y20 ; Automatically linear
X20 Y0 R-20 ; Arc move > 180 deg
Do not use the R radius specification if using the axis transformation matrices for scaling purposes with
the AROT or IROT statements. The radius value will not scale with the axes.
J
I
I
CENTER
(15,20)
START
(25,20)
END
(15,10)
X
X
Y
Y
CIRCLE2
TM1000
X
15Y10I-10
X
Y
START (10,0)
END
(0,10)
2
1
CIRCLE2
TM2000
X
0Y10R-10
CIRCLE2
TM2000
X0Y10R10
1
2
X
X
Y
Y
I
J
CENTER
(20,20)
START,END
(30,10)
X
X
Y
Y
NORMAL K-1
,Y)ABS (X
INC (R)
CIRCLE1
F10
X25Y30I20J5
START
(10,5)
CENTER
(30,10)
END
(25,30)
Defaults
CIRCLE1
F25
X30Y10I-10J10
or
I-10J10
Figure 32 PMAC Circular Interpolation
No Center Specification
If there is neither a vector specification nor a radius specification on a given move command line, the
move will be linearly interpolated between start and end points, even if the program is in circular move
mode. However, cutter compensation will not work properly if this is done. LINEAR move mode must
be explicitly declared if cutter compensation is on.