Siemens S7-400 - Page 16

Properties and services
1.3 Communication services
CP 443-1 Advanced
16 Equipment Manual, 03/2023, C79000-G8976-C256-07
• S7 communication with the following functions:
– PG functions
– Operator monitoring and control functions
– Data exchange over S7 connections
• Open communication services with the following functions:
– SEND/RECEIVE interface over ISO transport connections
– SEND/RECEIVE interface over TCP connections, ISO-on-TCP and UDP connections
With the SEND/RECEIVE interface via TCP connections, the CP supports the socket
interface to TCP/IP available on practically every end system.
UDP frame buffering on the CP can be disabled during configuration. When necessary,
this allows you to achieve a shorter reaction time between the arrival of a UDP frame
and its evaluation on the CPU.
– Multicast over UDP connection
The multicast mode is made possible by selecting a suitable IP address when
configuring connections.
– FETCH/WRITE services (server services; corresponding to S5 protocol) via ISO transport
connections, ISO-on-TCP connections and TCP connections;
Here, the SIMATIC S7-400 with the CP is always the server (passive connection
establishment) while the read or write access (client function with active connection
establishment) is always initiated by a SIMATIC S5 or a third-party device / PC.
– LOCK/UNLOCK with FETCH/WRITE services (CPU-dependent; see section Requirements
for use (Page 31))
• Open TCP/IP communication
Open TCP/IP communication provides a program interface for the transfer of connection-
oriented and connectionless services. The establishment and termination of connections is
initiated here only via the "dynamic" program interface.
STEP 7 provides a UDT for the connection description as well as four FBs for data
exchange.
The CP supports communication via ISO-on-TCP connections for this interface.
• SIMATIC Safety - Fail-safe communication
The CP supports fail-safe communication via S7 connections. A fail-safe connection can
run from the local CPU via the CP to the relevant communications partner, for example
another F-CPU or a fail-safe distributed I/O system.
You do not need to configure any special safety relevant properties for the CP.
• IT functions
– HTTP
– Web server: Monitoring devices and process data (HTML process control)