Siemens CPU 410-5H Process Automation System Manual page 225

The S7-400 features integrated S7 communication services that allow the user program in
the controller to initiate reading and writing of data. The S7 communication functions are
called in the user program using SFBs. These functions are independent of specific
networks, allowing you to program S7 communication via PROFINET, Industrial Ethernet, or
PROFIBUS.
S7 communication services provide the following options:
● During system configuration, you configure the connections used by the
● You can establish several connections to the same partner. The number of
● You can configure fault-tolerant S7 connections using the integrated PROFINET IO
S7 communication allows you to transfer a block of up to 64 Kbytes per call to the SFB. An
S7-400 transfers a maximum of 4 tags per block call.
SFBs for S7 Communication
The following SFBs are integrated in the operating system of the S7-400 CPUs:
Table 16- 6 SFBs for S7 Communication
Block Block name
SFB 8 USEND
SFB 9 URCV
SFB 12 BSEND
SFB 13 BRCV
SFB 14 GET
SFB 15 PUT
SFB 16 PRINT
SFB 19 START
SFB 20 STOP
SFB 22 STATUS
SFB 23 USTATUS
CPU 410-5H Process Automation/CPU 410 SMART
System Manual, 10/2013, A5E32631667-AA
S7 communication. These connections remain configured until you download a new
configuration.
communication partners accessible at any time is restricted to the number of connection
resources available.
interface.
Note
Downloading the connection configuration during operation
When you load a modified connection configuration during operation, connections which
have been set up which are not affected by changes in the connection configuration may
also be aborted.
Brief description
Send data to a remote partner SFB of type "URCV"
Receive asynchronous data from a remote partner SFB of type "USEND"
Send data to a remote partner SFB of type "BRCV"
Receive data from a remote partner SFB of type "BSEND"
With this data transfer, a larger amount of data can be transported between the
communication partners than is possible with all other communications SFBs for the
configured S7 connections.
Read data from a remote CPU
Write data to a remote CPU
Send data via a CP 441 to a printer
Carry out a reboot (warm restart) or cold restart in a remote station
Set a remote station to STOP operating state
Query the device status of a remote partner
Uncoordinated receiving of a remote device status
Supplementary information
16.6 Communication services
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