Detailed description 
  2.6 Interface  structure 
Basic logic functions: PLC basic program solution line (P3 sl) 
Function Manual, 11/2006, 6FC5397-0BP10-2BA0 
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2.6  Interface structure 
Interface data blocks 
Mapping in interface data blocks is necessary due to the large number of signals exchanged 
between the NCK and PLC. These are global data blocks from the viewpoint of the PLC 
program. During system start-up, the basic program creates these data blocks from current 
NCK machine data (no. of channels, axes, etc.). The advantage of this approach is that the 
minimum amount of PLC RAM required for the current machine configuration is used. 
2.6.1  PLC/NCK interface 
General 
The PLC/NCK interface comprises a data interface on one side and a function interface on 
the other. The data interface contains status and control signals, auxiliary functions and G 
functions, while the function interface is used to transfer jobs from the PLC to the NCK. 
Data interface 
The data interface is subdivided into the following groups: 
•  NCKspecific signals 
•  Mode-groupspecific signals 
•  Channelspecific signals 
•  Axis/spindle/drivespecific signals 
Function interface 
The function interface is formed by FBs and FCs. The figure below illustrates the general 
structure of the interface between the PLC and the NCK.