Predefined User Variables: Link Variables - Siemens Sinumerik 840D sl Programming Manual

1.1.4

Predefined user variables: Link variables

Function
Link variables can be used in the context of the "NCU-Link" function for cyclic data exchange
between NCUs which are linked on a network. They facilitate data-format-specific access to
the link variables memory. The link variables memory is defined both in terms of size and data
structure on a system-specific basis by the user/machine manufacturer.
Link variables are system-global user variables which can be read and written in part
programs and cycles by all NCUs involved in a link if link communication has been
configured. Unlike global user variables (GUD), link variables can also be used in
synchronized actions.
On systems without an active NCU link, link variables can be used locally on the control as
additional global user variables alongside global user variables (GUD).
Syntax
$A_DLB[<index>]
$A_DLW[<index>]
$A_DLD[<index>]
$A_DLR[<index>]
Significance
$A_DLB:
$A_DLW:
$A_DLD:
$A_DLR:
Job planning
Programming Manual, 02/2011, 6FC5398-2BP40-1BA0
Link variable for BYTE data format (1 byte)
Data type:
Range of values:
Link variable for WORD data format (2 bytes)
Data type:
Range of values:
Link variable for DWORD data format (4 bytes)
Data type:
Range of values:
Link variable for REAL data format (8 bytes)
Data type:
Range of values:
UINT
0 to 255
INT
-32768 to 32767
INT
-2147483648 to 2147483647
REAL
-308 +308
±(2,2*10 ... 1,8*10
Flexible NC programming
1.1 Variables
)
23