Parameter Assignment: Link Communication - Siemens SINUMERIK 840D sl Function Manual

Notes on setting
Cycle clock settings
It is recommended the following settings are made:
● The default 90% setting for the CPU time share of the NCK should be retained:
MD10185 $MN_NCK_PCOS_TIME_RATIO
● The system cycle clocks must be set so that the average system utilization caused by the
interpolator and the position controller does not exceed 60% in normal program operation.
As maximum value, 90% should be not be exceeded.
Note:
In special circumstances, maximum values > 100% can be displayed.
Lowest cyclic communication load
The lowest cyclic communication load during the link communication results for a cycle clock
ratio of interpolator cycle clock to position control cycle clock of 1:1. With activated "Dynamic
Servo Control (DSC)" drive function, this is generally the most effective setting.
Disadvantage: No telegram repetitions are possible for the link communication.
Time frame of the NC/PLC interface update
The following setting is active during the run-up of all NCUs involved in the link group:
MD18000 $MN_VDI_UPDATE_IN_ONE_IPO_CYCLE = 1
This causes the NC/PLC interface to be read and written completely in just one interpolation
cycle.
3.2.1.4

Parameter assignment: Link communication

NC-specific machine data
Number Identifier $MN_
MD12510 NCU_LINKNO
MD18780 MM_NCU_LINK_MASK.Bit 0
MD18781 NCU_LINK_CONNECTIONS
MD18782 MM_LINK_NUM_OF_MODULES
Extended Functions
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
Meaning
Unique numerical identification of the NCU within the link group. The
identifiers must be assigned without any gaps in ascending ordering
starting from 1.
Value range: 1, 2, ... Maximum NCU number
Note:
The NCU to which the value 1 is assigned as NCU identification is the
master NCU of the link group. The parameterization of link axes and axis
containers may only be made with the machine and setting data of the
master NCU.
Activation of the link communication
Number of internal link connections
Note:
It is recommended to retain the default value 0 (determination of the
number by the NC).
Number of NCUs to be connected with one another via NCU link.
B3: Distributed systems - 840D sl only
3.2 NCU link
89