Programming - Siemens SINUMERIK 840D sl Function Manual

Drive distribution and communications utilization
In a system with several NCUs that in conjunction with axis containers alternately traverse
axes of another NCU (link axes), the distribution of the drives connected to the NCU decides
the utilization of the link communication.
● Symmetric drive distribution
In the case of a symmetric drive distribution, the drives addressed via the axis container
are connected to both NCUs. On account of this arrangement, the maximum possible
number of drives can still be addressed via the logical machine axes images (LAI) on both
NCUs.
Figure 3-16
● Asymmetric drive distribution
In the case of an asymmetric drive distribution, the drives addressed via the axis container
are only connected to NCU1. On account of this arrangement, the maximum possible
number of drives can only be addressed via the logical machine axes images (LAI) on
NCU2. Only the maximum number minus the drives used by NCU2 can be addressed via
the LAI of NCU1. In order to also be able to use the maximum number of drives on NCU1,
they must be connected to NCU2 and addressed from NCU1 via the NCU link. This results
in a higher cyclic link communication load.
Figure 3-17
3.2.4.3

Programming

Function
The AXCTSWE or AXCTSWED commands are used to enable the rotation of the specified axis
container.
Any previously set enable for axis container rotation is cancelled with the AXCTSWEC command.
Extended Functions
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
Symmetric drive distribution
Asymmetric drive distribution
B3: Distributed systems - 840D sl only
3.2 NCU link
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