Siemens SINUMERIK 840D sl Function Manual page 1319

MCP interface in the PLC
The signals from the machine control panel are routed by default via the I/O interface to the
PLC area. A distinction must be made between NC and machinespecific signals. NC-specific
key signals are distributed to the relevant mode-group-, NCK-, axis- and spindle-specific
interface by FC19 (or FC24, FC25, FC26, depending on the type of MCP) by default. The
reverse applies to the associated status signals, which are routed to the MCP interface. For
this purpose, FC 19 or the other blocks mentioned above must be called in the user
program.
Customized keys, which can be used to trigger a wide range of machine functions, must be
evaluated directly by the user program. The user program also routes the status signals to
the output area for the LEDs.
Figure 2-11 Interface to and from machine control panel
Basic logic functions: PLC basic program solution line (P3 sl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Detailed description
2.6 Interface structure
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