Coupling Of The Plc Cpus; General; Features Of Plc Cpus; Interface With Integrated Plc - Siemens SINUMERIK 828D Function Manual

13.6

Coupling of the PLC CPUs

13.6.1

General

The AS 300 family is used as PLC for SINUMERIK 840D sl / 840Di sl. The PLC-CPU is integrated into the NCU
component as a sub-module. The relevant performance data for PLC CPUs can be found in the table in "Key
data of the PLC-CPUs for 840D sl and 840Di sl [Page 839]" or in the SIMATIC Catalog.
13.6.2

Features of PLC CPUs

SINUMERIK 840D sl / 840Di sl PLC CPUs are based on standard SIMATIC CPUs in the S7-300 family. As a
result, they generally possess the same functions. The deviations can be taken from the Table in "Key data of the
PLC-CPUs for 840D sl and 840Di sl [Page 839]". Owing to differences in their memory system as compared to
the SIMATIC CPU, certain functions are not available (e.g. save blocks on memory card, save project on memory
card).
Note
With the current SIMATIC CPUs, the PLC is not automatically started after voltage failure
and recovery when a PLC Stop is initiated via software operation. In this instance, the PLC
remains in the Stop state with an appropriate diagnostic entry for safety reasons. You can
start the PLC only via software operation "Execute a restart" or by setting the switch to "Stop"
and then "Run". This behavior is also integrated in the current versions of the SINUMERIK
PLC.
13.6.3

Interface with integrated PLC

Physical interfaces
As the SINUMERIK 840D sl / 840Di sl system has an integrated PLC, signals can be exchanged between the
NCK and PLC directly via a dual­port RAM.
Data exchange with the control panel
Data exchange with the operator panel (HMI, OP) usually takes place via the internal software-based C bus.
Alternatively, external HMI or OP systems can also be connected on Ethernet or the MPI bus. In the event of
connection to the Ethernet bus, the integrated CP provides the link to the PLC.
Data exchange with the machine control panel (MCP) and handheld unit (HHU) is realized depending on the
interface version of the MCP or HHU. Possible connection paths include: MPI, PROFIBUS, Ethernet.
Programming devices should preferably be connected directly to the PLC on the Ethernet bus via the internal CP
or via the MPI (Multi-Point-Interface).
Basic Functions
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
P3: Basic PLC Program for SINUMERIK 840D sl
13.6 Coupling of the PLC CPUs
859