Siemens SINUMERIK 840D sl Function Manual page 175

Machine data
MD18780 $MN_MM_NCU_LINK_MASK
This machine data ensures that link communication is established. It provides the dynamic
memory space that is required for communication in the NCUs equipped with link modules.
The machine data below determines the data transfer rate of link communication based on
the assignments listed below:
MD12540 $MN_LINK_BAUDRATE_SWITCH
Set value/Rate:
0: 9,600 Kbaud
1: 19,200 Kbaud
2: 45,450 Kbaud
3: 93,750 Kbaud
4: 187,500 Kbaud
5: 500,000 Kbaud
6: 1,500 Mbaud
7: 3,000 Mbaud
8: 6,000 Mbaud
9: 12,000 Mbaud (default setting)
Machine data:
MD12550 $MN_LINK_RETRY_CTR
specifies the maximum number of times the link communication is automatically repeated
when an error occurs during frame transfer.
The machine data below specifies the number of link modules taking part in the link
communication:
MD12530 $MN_LINK_NUM_OF_MODULS
The following machine data assigns a logical link number to an NCU; this number is used for
link identification in conjunction with link axes and link communication:
MD12510 $MN_NCU_LINKNO
Identifications can be assigned independently of the physical sequence of the modules in the
link string. The module with NCU_LINKNO = 1 is master.
Assignment of NCU_LINKNO must be unambiguous. An alarm is issued if there is an error.
The machine data below specifies for the software which NCUs correspond to the bus
terminating resistors:
MD12520 $MN_LINK_TERMINATION
Extended Functions
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Several Operator Panels on Several NCUs, Distributed Systems (B3)
WARNING
Configuration of a link grouping
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