Rockwell Automation 20-750-ENETR PowerFlexDual-Port EtherNet/IP Option Module - Manual (Page 192)

192 Rockwell Automation Publication 750COM-UM008A-EN-P - July 2012
Glossary
IP Addresses A unique IP address identifies each node on an EtherNet/IP network. An IP
address consists of 32 bits that are divided into four segments of one byte each. It
appears as four decimal integers separated by periods (xxx.xxx.xxx.xxx). Each
“xxx” can have a decimal value from 0 to 255. For example, an IP address could be
192.168.0.1.
An IP address has two parts: a network ID and a host ID. The class of network
determines the format of the address.
The number of devices on your EtherNet/IP network will vary depending on the
number of bytes that are used for the network address. In many cases you are
given a network with a Class C address, in which the first three bytes contain the
network address (subnet mask = 255.255.255.0). This leaves 8 bits or 256
addresses on your network. Because two addresses are reserved for special uses (0
is an address for the network usually used by the router, and 255 is an address for
broadcast messages to all network devices), you have 254 addresses to use on a
Class C address block.
To be sure that each device on the Internet has a unique address, contact your
network administrator or Internet Service Provider for unique fixed IP addresses.
You can then set the unique IP address for the option module by using its rotary
address switches, a DHCP or BOOTP server, or by manually configuring
parameters in the option module. The option module reads the values of these
parameters only at power-up.
Logic Command/Logic Status The Logic Command is used to control the PowerFlex 750-Series drive (for
example, start, stop, direction). It consists of one 32-bit word of output to the
option module from the network. The definitions of the bits in this word are
shown in
Appendix D .
The Logic Status is used to monitor the PowerFlex 750-Series drive (for example,
operating state, motor direction). It consists of one 32-bit word of input from the
option module to the network. The definitions of the bits in this word are shown
in
Appendix D .
Master-Slave Hierarchy An option module configured for a master-slave hierarchy exchanges data with
the master device. Usually, a network has one scanner which is the master device,
and all other devices (for example, drives with installed EtherNet/IP Option
Modules) are slave devices.
On a network with multiple scanners (called a multi-master hierarchy), each slave
device must have one scanner specified as a master.
0 1 7 15 23 31
Class A 0 Network ID Host ID
0 1 7 15 23 31
Class B 1 0 Network ID Host ID
0 1 2 7 15 23 31
Class C 1 1 0 Network ID Host ID