Interface Structure; Plc/Nck Interface - Siemens SINUMERIK 828D Function Manual

P3: Basic PLC Program for SINUMERIK 840D sl

13.7 Interface structure

13.7 Interface structure
Interface DBs
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.
13.7.1

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
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Function Manual, 09/2011, 6FC5397-0BP40-2BA0
Basic Functions