Siemens SINUMERIK 840C - Manual (Page 786)

09.95 12 Functional Descriptions
12.2.2 Functional description
with calculation, and with G68, the programmed position is always approached over the
shortest path.
G68 is modal and belongs to the G90/91 group. If "modulo programming" is not activated,
G68 is treated like G90.
If the rotary axis is not to traverse over the shortest path, it must be programmed with G90
and a sign.
Example: Axis is at 270 degrees
N10 G68 C10
N11 G90 C10
N12 G90 C-10
90 270
N12
0
180
N10
N11
The machine data "Modulo 360°" and "Modulo programming" are permissible only in
conjunction with machine data "Rotary axis".
Subfunction combinations
Rotary axis Modulo prog. Modulo 360° Comments
564* Bit5 572* Bit 2 560* Bit 7 MD
0 0 0 Linear axis
1
1
1 0
0
1 0
1
1
Use permitted
1
0
0
0 1
0
1
1 0
1
1
0
Use illegal
Axis-specific machine data
If an axis is defined as rotary axis (NC MD 564, bit 5), the following applies in dependence on
NC MD (input resolution and position control resolution):
a) 1 unit = 2 units of position control resolution (reference system MS)
e.g. 1 unit of position control resolution = 0.5 x 10 -3 degrees
(NC MD 1800* = xxxxx 0101)
1 unit = 10 -3 degrees
b) 1 unit = 1 unit of input resolution (reference system IS)
e.g. 1 unit of input resolution = 10 -3 degrees (NC MD 5002 = x0100 xxxx)
1 unit = 10 -3 degrees
All axis-specific machine data is specified in degrees for a rotary axis, e.g. max. speed of a
rotary axis = 15 revs/min
15 revs/min x 360 degrees/rev = 5400 degrees/min
Entry in NC MD 280* = 5400 (1000 degrees/min)
For combinations of the various types of resolution and max. values, refer to the Section on
axis installation/start-up.
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 12–11
SINUMERIK 840C (IA)