Siemens SINUMERIK 840Di Function Manual page 1227

2.6.3 PLC/MCP/HHU interface
General
There are three different connection options for the machine control panel (MCP) and the
handheld unit (HHU). This is in part due to the history of the MCP and HHU. This description
focuses primarily on the connection of the Ethernet components.
On SINUMERIK 840 D, the machine control panel (MCP) and handheld unit (HHU) are
connected via the Ethernet bus, which also links the TCU to the NCU. The advantage of this
is that only one bus cable is required to connect the operator unit.
840D topology
On the 840 D, the machine control panel and the handheld unit are connected to the CP
840D sl Ethernet bus (Fig. 9). Where the connection of further keys and displays is required
for customized operator panels, an additional keyboard interface (machine control panel
without operating unit) can be used. For each keyboard interface, 64 pushbuttons, switches,
etc. and 64 display elements can be connected via ribbon cable.
The signals sent from the MCP are copied to the PLC's DPR (Dual Port RAM) by the
integrated Ethernet CP-840D sl. The basic program of the PLC enters the incoming signals
in the input image configured on FB1. NCK-relevant signals are usually distributed by the
basic program to the VDI interface. If required, the signals can be modified by the user.
The signals from the PLC to the MCP (displays) are transferred in the opposite direction.
PLC Basic Program Solution Line (P3 sl)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Detailed Description
2.6 Interface structure
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