Siemens sinumerik 840d Programming Manual page 455

12.98
13
840D 840D
NCU 571 NCU 572
NCU 573
• Relatively small data volume
• Very high transfer speed,
therefore: Use is intended for time-critical
information.
• These system variables can be accessed from
the part program and from synchronized
actions. The size of the memory area for global
NCU system variables is configurable.
When a value is written in a global system variable, it
can be read by all the NCUs connected after one
interpolation cycle.
Link variables are global system data that can be
addressed by the connected NCUs as system
variables. The
– contents of these variables,
– their data type,
– use, and
– position (access index) in the link memory
are defined by the user (in this case generally the
machine manufacturer).
Link variables are stored in the link memory.
After power-up, the link memory is initialized with 0.
The following link variables can be addressed within
the link memory:
• INT $A_DLB[i]
• INT $A_DLW[i]
• INT $A_DLD[i]
• REAL $A_DLR[i]
According to the type in question, 1, 2, 4 or 8 bytes
are addressed when the link variables are
written/read.
Index i defines the start of the respective variable in
relation to the start of the configured link memory.
The index is counted from 0 up.
 Siemens AG 2000. All rights reserved
SINUMERIK 840D/840Di/810D/FM-NC Programming Guide Advanced (PGA) – 04.00 Edition
13.6 Link communication (SW 5.2 and higher)
FM-NC 810D 840Di
; data byte (8 bits)
; data word (16 bits)
; double data word (32 bits)
; real data (64 bits)
Additional Functions
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