Link Communication - Siemens SINUMERIK 840D sl Programming Manual

13.8

Link communication

13.8
Function
The NCU link, the link between several NCU units of an installation, is used in distributed
system configurations. When there is a high demand for axes and channels, e.g. with
revolving machines and multi-spindle machines, computing capacity, configuration options
and memory areas can reach their limits when only one NCU is used.
Several NCUs interconnected with an NCU link module provide a scalable solution which
fully meets the requirements of this type of machine tools. The NCU link module (hardware)
realizes a fast NCU-to-NCU communication by providing read and write access to system
variables.
Requirements
Options providing this functionality can be ordered separately.
Link variables
Link variables are global system data that can be addressed by the connected NCUs as
system variables.
The user (in this case, normally the machine manufacturer) specifies:
• the contents of these variables,
• their data type,
• their use,
• their position (access index) in the link memory.
Applications for link variables:
• global machine states,
• workpiece clamping open/closed
• etc.
Job planning
Programming Manual, 03/2006 Edition, 6FC5398-2BP10-1BA0
Additional functions
13.8 Link communication
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