User Communication Across The Ncus - Siemens SINUMERIK 840D sl Function Manual

Several Operator Panels on Several NCUs, Distributed Systems (B3)
2.1 Brief Description
2.1.4.5

User communication across the NCUs

Link variables
● Every NCU connected by means of a link module can address uniformly accessible
● Applications for link variables:
● Data volume comparatively small
● Transmission rate very high because information relevant to main run is available for
● These system variables can be accessed from the part program and from synchronized
● All connected NCUs require one interpolation cycle before they can consistently read a
Figure 2-9
Note
On installations without an NCU link, the link variables can also be used NCU-locally as
an additional means of cross-channel communication.
In this case no interpolation cycle elapses between writing and reading.
References:
/FBSY/ Function Manual Synchronized Actions
98
global link variables for all connected NCUs. Link variables can be programmed in the
same way as system variables. As a rule, the machine manufacturer defines and
documents the meanings of these variables.
– global machine states,
– Workpiece clamping open/closed
– ...
exchange.
actions. You can configure the size of the memory area for global system variables.
new value in a global system variable.
Communication overview
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
Extended Functions