Siemens SINUMERIK 840Di Function Manual page 1214

Detailed Description
2.5 Linking PLC CPUs to 840D
Exchange with the operator panel front
Data exchange with the operator panel (HMI, OP) usually takes place via the internal
software-based C bus. Alternatively, external HMI or OP systems can also be connected on
Ethernet or the MPI bus. In the event of connection to the Ethernet bus, the integrated CP
provides the link to the PLC. On the 840D, data exchange with the machine control panel
(MCP) and handheld unit (HHU) is determined by the interface setup of the MCP/HHU.
Possible connection paths include: MPI, PROFIBUS, Ethernet.
Programming devices should be connected to the Ethernet bus via the internal CP or via the
MPI (Multi-Point-Interface) directly to the PLC.
Fig. 2-3
2-20
NCK/PLC coupling on 840D (integrated PLC)
PLC Basic Program Solution Line (P3 sl)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0