Further Services And Characteristics Of The Cp - Siemens SIMATIC S7-CPs Manual

S S5-compatible communication 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 fetch or write access (client function
with active connection establishment) is always initiated by a SIMATIC S5 or
a device from another range / PC.
− LOCK/UNLOCK with FETCH/WRITE services (CPU-dependent; see
Chapter 2);
1.3

Further services and characteristics of the CP

S Media redundancy
Within an Ethernet network with a ring topology, the CP supports the media
redundancy protocol MRP. You can assign the role of redundancy manager to
the CP.
S Time-of-day synchronization over Industrial Ethernet according to the following
configurable method:
− SIMATIC mode
The CP receives MMS time-of-day messages and synchronizes its local
time.
You can choose whether or not the time of day is forwarded. You can also
decide on the direction in which it is forwarded.
or
− NTP mode (NTP: Network Time Protocol)
The CP sends time-of-day queries at regular intervals to an NTP server and
synchronizes its local time of day.
The time can also be forwarded automatically to the CPU modules in the S7
station allowing the time to be synchronized in the entire S7 station.
CP 443-1 for Industrial Ethernet / Manual Part B
Release 07/2010
C79000-G8976-C223−06
1 Properties and Services
B−7