Restart after detection of a duplicate IP address in the network
To save you timeconsuming troubleshooting in the network, during startup the CM detects
double addressing in the network.
Behavior when the CM starts up
If double addressing is detected when the CM starts up, the CM changes to RUN and cannot
be reached via the Ethernet interface. The ERROR LED flashes.
Remove retentive storage of the IP address if there are duplicate addresses
The IP address and the device name of the CM 1542-1 remain installed retentively:
If, for example during startup, the CM detects a duplicate address in another network, the
CM is not connected to the network. The CM changes to RUN and cannot be reached via
the Ethernet interface.
To be able to connect the CM to the network, you can remove the retentively stored IP
address as follows:
1. Remove the memory card of the CPU.
2. Using DCP with the Primary Setup Tool (PST) and with the CPU in STOP, set the IP
address of the CM to 0.0.0.0 without configuration.
You have removed the retentively stored IP address of the CM. The CM can be
connected into the network.
3. Insert the memory card in the CPU again.
IP routing via the backplane bus
The CM supports static IP routing (IPv4) to other CM 1542-1 / CP 1543-1 as of firmware
You can use IP routing, for example, for Web server access by lower-level modules.
With IP routing, he data throughput is limited to 1Mbps. Remember this in terms of the
number of modules involved and the expected data traffic via the backplane bus.
IP routing must be activated in at least 2 modules of a station.
IP routing runs via the configured default router. If you use several CMs/CPs in a station, of
the modules in the station only one may be configured as a router.
Operating Instructions, 07/2019, C79000-G8976-C355-04
4.3 IP configuration