Siemens SINUMERIK 840D sl Function Manual page 171

B3: Several operator panels connected to several NCUs, distributed systems - only 840D sl
The byte addressed by link variable $A_DLB[0] is only written to N120 if the write job can
be transferred to the other NCUs in the link grouping in the same interpolation cycle. If this is
the case, the link variable is written and the system variable decremented at the same time.
A block change then takes place and N125 is processed in the same way.
If it is not possible for the write job to be executed immediately in N120, an attempt is made
to execute the write process in the next interpolation cycle.
Example
The following data is required for link communication:
Data format
BYTE
WORD
DWORD
REAL
The data is arranged in the link variables memory as follows, with the data format limits
taken into account:
Figure 2-24
Note
Memory structure
The data in the link variables memory is always arranged randomly and may therefore
appear different (although the data format limits will still be taken into account).
Access via a link variable must be programmed as follows, in accordance with the memory
structure defined:
Extended Functions
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
Number
2
1
3
1
Example: Structure of the link variables memory
Bytes required
2
2
12
8
24 (required size of the link variables memory)
2.8 Link communication
171