A4: Digital and analog NCK I/Os for SINUMERIK 840D sl
1.3 Access via PROFIBUS
Extended Functions
Function Manual, 03/2013, 6FC5397-1BP40-3BA1
55
Data exchange
The data exchange with the PROFIBUS I/O is performed 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
part programs / synchronized actions in the IPO cycle (data consistency). The
PROFIBUS I/O data to be written is output at the PROFIBUS I/O only after the
corresponding IPO cycle.
See "Communication via part programs/
synchronous actions (Page 58)".
● Read in / output of the data blocks via the compile-cycle interface (data consistency for
servo cycle).
See "Communication via compile cycles (Page 61)".
Parallel data access
A parallel read access through compile cycles and part programs / synchronized 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.
A parallel write access through compile cycles and part programs / synchronized actions on
data of the same I/O range is not possible. While configuring the NCK it must be determined,
whether a specific I/O range of the PROFIBUS I/O is allocated to the system variables or to
the compile cycles.
Activation
The function is activated during the NCK run-up.
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