Okuma OSP-P20L - Page 40

5238-E P-27
SECTION 3 MATH FUNCTIONS
For I and K, signed incremental values are used regardless of the mode, G90 or G91.
LE33013R0300500030003
Determining Sign and Numeric Value of I and K Words:
See the figure below. Assume the coordinate system has its origin at the arc start point. Draw a
right-angled triangle taking the segment connecting the arc center and arc start point as the
hypotenuse. The length of side (b), parallel to the Z-axis, is the value of the K word and that of
side (c), parallel to the X-axis, is the value of the I word.
Concerning the sign of these words, when side (b) lies in the positive direction of the assumed
coordinate system, it is taken as a positive value and when it lies in the negative direction, it is
negative. The sign of I words is determined in a similar way. That is, when side (c) lies in the
positive direction of the coordinate system, the I word has a positive value and when it lies in
the negative direction, the I word has a negative value.
LE33013R0300500030004
X(I)
Z
1
X1
φ
Arc center
Arc end point
R
K
1
Z(K)
Arc start point
G02: Both I and K values are positive
Z
1, X1 indicate the coordinate values
of the arc end point.
I
X(I)
Z
1
X1
Arc
center
Arc end point
Arc start point
K
R
Z(K)
G03: Both I and K values are positive
Z
1, X1 indicate the coordinate values of
the arc end point
φ
I
X-axis
Z-axis
Arc start point
Arc center
ID cutting
IOD cutting
I +
I +
I -
I -
K +
K -
K -
K -
K -
I - K -
I + K -
(a)
(c)
(b)