04.97
Programming of Traversing Blocks
4.2.2
Rotary axis, shortest distance G68
If the WF axis is used as a rotary axis, the measuring system should be ajusted in such a way
that the dimensions refer to a full circle (e.g. 1°/1000), so that the positions that can be
reached lie between 0° and 360°. Any other adjustment is also possible.
•
Absolute dimension G90
When using a full circle with 360°, the input of absolute dimensions (G90) has the
particularity that there are always 2 possibilities to reach the set position.
Programming the direction of rotation
The axis traverses to the programmed
position, the sign of the position value
defining the traversing direction:
+:
Traversing in the direction of increasing
degrees (actual values)
– : Traversing in the direction of decreasing
degrees (set values)
315
o
45
o
0
o
180
o
225
o
270
o
135
o
90
o
Actual
position
315
o
45
o
0
o
180
o
225
o
270
o
135
o
90
o
Actual
position
Programmed
position
Programmed
position
Programming:
N10 G90 G68 C315.000 FC1000.00
Programming:
N10 G90 C315.000 FC1000.00
(or N10 G90 C-315.000 FC1000.00)
G68 - shortest distance
When G68 is programmed, the axis moves
to the programmed position, traversing the
shortest possible distance and ignoring the
sign of the position value. G68 is effective
block by block.
•
Incremental dimension G91
When the incremental dimension G91 is programmed, the direction of rotation of the rotary
axis is determined by the sign of the position set value. Several revolutions may be
programmed if a multiple of 360° is defined as the position set value.
If G68 is programmed in connection with G91, an error message will be output.
©
Siemens AG 1997 All Rights Reserved 6ZB5 440-0VU02
4 – 3
WF 723 C (Programming Guide)
