Siemens SINUMERIK 840D sl Function Manual page 188

B3: Several operator panels connected to several NCUs, distributed systems - only 840D sl
2.12 NCU link with different interpolation cycles
Motion sequences
While the workpiece is rotating about the C axis, the X axis must be advanced with high
precision between the smallest and largest radius/diameter according to the required shape
(sine, double sine, etc.). In general, a smaller linear movement per rotation is sufficient in Z
direction. If the workpiece is to be moved at a typical speed (e.g. 3000 rpm), the X axis must
be highly dynamic. This means:
● shorter interpolation cycle
● shorter position control cycle
compared to the requirements of the C and Z axis.
Solution
The requirements described in the motion sequences are met by an NCU link grouping;
where the NCU with the shorter interpolation cycle drives the highly dynamic X axis and
another NCU with standard interpolation cycle drives the less dynamic C and Z axes.
General polynomials are used to specify the motion for the X axis.
Note
The NCU constellation with different interpolation cycles - where one is always faster than
the others - is called "FAST-IPO-LINK" in alarm messages.
Figure 2-31
188
NCU link with different interpolation cycles
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
Extended Functions