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Rockwell Automation Publication 1769-UM021G-EN-P - October 2015
Chapter 4
Complete Software Tasks Required at CompactLogix 5370 Controller Installation
Use the DHCP Server to Set the IP Address of the Controller
Dynamic Host Configuration Protocol (DHCP) server automatically assigns IP
addresses to client stations logging on to a TCP/IP network. DHCP is based on
BOOTP and maintains some backward compatibility. The main difference is
that BOOTP manual configuration (static), while DHCP enables static and
dynamic allocation of network addresses and configurations to newly attached
controllers.
Be cautious when using the DHCP server to configure a controller. A BOOTP
client, such as the CompactLogix 5370 controllers, can start from a DHCP
server only if the DHCP server is written to handle BOOTP queries. This
requirement is specific to the DHCP server used. Consult your system
administrator to see if a DHCP server supports BOOTP commands and manual
IP allocation.
If you use the Rockwell Automation BOOTP or DHCP server in an uplinked
subnet where a DHCP server exists, a controller can procure an address from the
enterprise server before the Rockwell Automation utility even sees the controller.
Disconnect from the uplink to set the address and configure the controller to
retain its static address before reconnecting to the uplink, if necessary.
ATTENTION:
Assign the CompactLogix 5370 controllers a fixed network
address. The IP address of this controller is not to be dynamically provided.
Failure to observe this precaution can result in unintended machine motion or
loss of process control.