Rockwell Automation 193-DNENCATR EtherNet/IP Communications Auxiliary User Manual - Manual (Page 22)

22 Rockwell Automation Publication 193-UM014B-EN-P December 2011
Chapter 2
Other Factors to Consider When Assigning Network Parameters
There are other factors to consider when assigning networks parameters, which
include the:
• network isolation from or integration into the plant/enterprise network.
• network size.
For large networks, even isolated networks, it might be more convenient
and safer to use a BOOTP/DHCP server rather than RSLinx software.
The BOOTP/DHCP server also limits the possibility of assigning
duplicate IP addresses.
• company policies and procedures associated with plant floor network
installation and maintenance.
• level of involvement by information technology personnel in plant floor
network installation and maintenance.
• type of training offered to control engineers and maintenance personnel.
If the Rockwell Automation BOOTP or DHCP server is used in an uplinked
subnet where an enterprise DHCP server exists, a module may get an address
from the enterprise server before the Rockwell Automation utility even sees the
module. In this case, disconnect the uplink to set the address and configure the
module to retain its static address before reconnecting to the uplink. This is not a
problem if you have node names configured in the module and leave DHCP
enabled.
Duplicate IP Address
Detection When you change the IP address or connect the module to an EtherNet/IP
network, the module checks to make sure that the IP address assigned to this
module does not match the address of any other network device. If the module
determines that another device on the network with a matching IP address, the
EtherNet/IP port of the module goes into conflict mode where the Network
Status LED indicator is solid red.
To resolve this conflict, use the instructions below to change the IP address of the
module. Then, cycle power to the module or reset the modules by disconnecting
and then reconnecting the Ethernet cable.
Two modules could possibly detect a conflict simultaneously. If this occurs,
perform this procedure.
1. Remove the module with the incorrect IP address and correct its conflict.
2. Cycle power or disconnect the Ethernet cable from the second module and
reconnect it.
ATTENTION:
The EtherNet/IP Communications Auxiliary must be
assigned a fixed network address. The IP address of this module must not
be dynamically provided. Failure to observe this precaution may result in
unintended machine motion or loss of process control.