Siemens SINUMERIK 840D sl Function Manual page 1030

Detailed description
2.6 Interface structure
840D topology
On the 840D, the machine control panel is connected to the OPI bus segment (transmission
rate 1.5 Mbps) as an active global data node. Where the connection of further keys and
displays is required for customized operator panels, an additional keyboard (machine control
panel without operating unit) can be used. 64 pushbuttons, switches, etc. and 64 display
elements can be connected via ribbon cable.
The signals arriving from the machine control panel are copied by the COM module into the
DPR (dualport RAM) for transfer to the NC. The NC in turn transmits them to the PLC (VDI
task). The basic program of the PLC enters the incoming signals in the input image. The NC-
related signals are generally distributed by the basic program to the VDI interface. This can
be modified by the user if required.
The signals (displays) from the PLC to the MCP (displays) are transferred in the opposite
direction.
The signals of the handheld unit (HHU) are transferred either via the operator panel interface
in the same way as via the machine control panel or by means of the GD service (GD =
Global Data) of the MPI interface. The PLC operating system enters the HHU data, for
example, in the input image and transfers the display values, e.g., from the output image,
back to the HHU. The corresponding parameters are set via system data block SDB210,
which is generated with the STEP7 communication configuration tool.
Figure 2-9
46
Connection of the machine control panel for 810D
Basic logic functions: PLC Basic program powerline (P3 pl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0