Siemens CP 343-1 Manual page 48

Configuration and operation
6.4 Network settings
Further notes:
● Autocrossover
If you disable the "Automatic setting" option, autocrossing is disabled; which cable you
then use depends on the integration of the CP (network component or end device).
● 10/100 Mbps network components without "autonegotiation"
If you use 10/100 Mbps network components that do not support "Autonegotiation", it is
possible that you will have to set the mode manually in the CP configuration in STEP 7.
As default, the CP is configured for automatic detection.
● Forcing a specific network setting instead of "Autonegotiation"
If your application requires a fixed network setting instead of "Autonegotiation", both
partner devices must have the same setting.
● No reaction to Autonegotiation query with manual configuration
Remember that if you configure the CP manually, it will not react to an autonegotiation
query! As a result, a connected partner will not be able to make the required network
setting and communication will not be established.
Example:
If the CP is set to "100 Mbps full duplex", a CP connected as partner will set itself to "100
Mbps half duplex". Reason: Due to the fixed setting, no autonegotiation response is
possible; the connected partner recognizes the 100 Mbps with autosensing but
nevertheless remains in 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 "Port Parameters"
tab, these changes will be adopted by the CP and activated when the configuration data
is downloaded to the CP. 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 over 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 setting" is now changed to 100 Mbps full duplex, the download cannot
be completed.
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Manual, 12/2018, C79000−G8976−C201-08
CP 343-1