Ip Configuration; Points To Note About Ip Configuration; Restart After Detection Of A Duplicate Ip Address In The Network - Siemens SIMATIC NET S7-400 Manual

● No reaction to Autonegotiation query with manual configuration
Remember that if you configure the CP manually and the "Autonegotiation" option is
disabled, it will not react to an autonegotiation query! As a result, a connected partner
may not be able to set the required mode and communication will not be ideal.
Example:
If the CP is set to "100 Mbps - full duplex" and autonegotiation is disabled, a CP
connected as partner will set "100 Mbps - half duplex". Reason: Due to the fixed setting,
an autonegotiation reply is not possible. Although the connected partner detects
100 Mbps with autosensing, it remains at half duplex.
● Recommendation: Change individual network settings only over MPI
If you modify the LAN settings in the properties dialog of the CP in the "Options" tab using
the "Transmission medium/Duplex" drop-down list, these changes will be adopted by the
CP and activated when the configuration data is downloaded to the target system
(STEP 7). In some situations, the device may then no longer be obtainable over Ethernet.
We therefore recommend that you download configuration data to the S7 station over an
MPI connection if you change this setting.
If you download the configuration data via the LAN interface then, depending on the
selected setting, it is possible that the current download will not be completed due to the
changes to the configuration taking immediate effect and an inconsistent configuration is
reported.
Example:
The download is started initially with the setting TP/ITP at 10 Mbps half duplex. If the
"Individual network settings" are now changed to 100 Mbps full duplex, the download
cannot be completed.
6.6.2

IP configuration

6.6.2.1

Points to note about IP configuration

Configured S7 connections cannot be operated if the IP address is assigned over DHCP
Note
If you obtain the IP address using DHCP, any S7 connections you may have configured will
not work. Reason: The configured IP address is replaced by the address obtained via DHCP
during operation.
6.6.2.2

Restart after detection of a duplicate IP address in the network

To save you timeconsuming troubleshooting in the network, the CP detects double
addressing in the network.
CP 443-1 (EX30)
Manual, 03/2019, C79000-G8976-C255-05
Configuration and operation
6.6 Interface configuration
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