Nck I/O Via Profibus; Functionality - Siemens SINUMERIK 840D sl Function Manual

Digital and analog NCK I/Os (A4)

1.3 NCK I/O via PROFIBUS

1.3 NCK I/O via PROFIBUS
1.3.1

Functionality

General
The function "NCK-I/O via PROFIBUS" implements a direct data exchange between NCK
and PROFIBUS-I/O.
The PROFIBUS-I/O is connected to the control. Like for any other PLC-I/O, an
S7-HW-configuration (PLC) must be done before using this PROFIBUS-I/O.
If the individual useful-data slots of a PROFIBUS-slave are configured in the
S7-HW-configuration (PLC) in such a way that they form a contiguous PROFIBUS-I/O
section in series, with logical start addresses in ascending order, then this section is
hereinafter referred to as I/O-region.
An I/O-region is characterized by:
● a logical start address (this corresponds to the logical start address of the first useful-data
● a configured length (this corresponds to the length in bytes of the connected
The logical start addresses of the I/O-range must be available in NCK, so that it can
read/write the corresponding data of the PROFIBUS-I/O via an NCK-internal PROFIBUS
communication interface. The projected I/O-range is registered via the machine data. The
communication with the PROFIBUS-I/O is thus possible only I/O-range oriented.
Data exchange
The data exchange with the PROFIBUS-I/O is done via an NCK-internal PROFIBUS-
communication interface. The following options of data exchange with the PROFIBUS-I/O
are available to the NCK-user:
● Reading/writing of NCK-system variables ($A_DPx_IN[n,m] or $A_DPx_OUT[n,m]) via
● Reading/printing the data blocks via the compile-cycle interface (data consistency for
Parallel data access
A parallel read access through compile cycles and part programs/synchronous actions on
data of the same I/O-range is possible, as long as the corresponding I/O-range has been
configured for this. One must ensure that the read accesses have access to the different
mappings of the PROFIBUS-I/O data. The data consistency within these mappings is
ensured. However, the data equality between these mappings cannot be ensured during an
IPO cycle.
54
slot of this I/O-range)
PROFIBUS-I/O to be accessed)
part programs /synchronous actions in the IPO cycle (data consistency). The PROFIBUS-
I/O data to be written is printed at the PROFIBUS-I/O only after the corresponding IPO
cycle.
Servo cycle)
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
Extended Functions