Link Module; Parameter Assignment: Nc System Cycles - Siemens SINUMERIK Series Function Manual

2.2.1.2

Link module

The NCU-link communication takes place via link modules A link module is an optional
PROFINET module for isochronous real-time communication (IRT) via Ethernet. The link
module can be used only for the NCU-link communication. It is not possible to use a link
module for general PROFINET communication.
The option slot is required on the NCU module for the link module.
Note
There is only one option slot on the NCU module. This prevents the parallel use of an NCU-
link module and other optional modules.
Link module and NCU modules
The Communication Board Ethernet CBE30-2 is available as link module for the "NCU710.3
PN", "NCU720.3 PN" and "NCU730.3 PN" NCU modules. The option slot is required on the
NCU module for the link module.
References
Manual NCU7x0.3 PN; "Connectable components" > "CBE30-2" section
2.2.1.3

Parameter assignment: NC system cycles

As basic requirement for link communication, the following system cycle clocks must be set
the same in all NCUs involved in the NCU group:
● Basic system cycle clock
● Position control cycle clock
● Interpolator cycle clock
Basic system cycle clock
The DP cycle set for isochronous communication in the STEP 7 project is used as basic
system cycle clock. The current basic system cycle clock is displayed in machine data:
MD10050 $MN_SYSCLOCK_CYCLE_TIME
Note
Manual alignment across several communications buses
If several isochronous communication buses (PROFIBUS 1 ... n, PROFINET 1 ... m) have
been configured on an NCU, the same DP cycle time in STEP 7 HW Config must be set for
each communication bus.
Depending on the position control cycle clock
For the SINUMERIK 840D sl, the ratio between the basic system cycle clock and the position
control cycle clocks is fixed (1:1) and cannot be changed. Because only certain position
control cycle clocks can be set for the NCU link, only these position control cycle clocks can
be set as the basic system cycle clock or DP cycle time. See the next paragraph "Position
control cycle clock".
Extended Functions
Function Manual, 03/2013, 6FC5397-1BP40-3BA1
B3: Distributed systems - 840D sl only
2.2 NCU link
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