Rockwell Automation Publication 750COM-UM009A-EN-P - May 2017 185
Glossary
The number of devices on your EtherNet/IP network 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 3-bytes contain the
network address (subnet mask = 255.255.255.0). This leaves 8-bits or 256
addresses on your network. Two addresses are reserved for special uses (0 is an
address for the network that is 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. Set the unique IP address for the interface by using the rotary
address switches, a DHCP, or BOOTP server, or by manually configuring the
parameters in the interface. The interface reads the values of these parameters
only at power-up.
Logic Command/Logic Status The logic command is used to control the PowerFlex 755T drive (for example,
start, stop, and direction). It consists of one 32-bit word of output to the
interface from the network. The definitions of the bits in this word are shown
in Appendix E
.
The logic status is used to monitor the PowerFlex 755T drive (for example,
operating state and motor direction). It consists of one 32-bit word of input
from the interface to the network. The definitions of the bits in this word are
shown in Appendix E
.
NVS (Nonvolatile Storage) NVS is the permanent memory of a device. Devices such as the interface and
drive store parameters and other information in NVS so that they are not lost
when the device loses power. NVS is sometimes called ‘EEPROM’.
PCCC (Programmable Controller
Communication Command)
PCCC is the protocol that is used by some controllers to communicate with
devices on a network. Some software products also use PCCC to
communicate.
Ping A message that is sent on the network to determine if a node exists.
PowerFlex 755T (Architecture Class)
Drives
The Allen-Bradley PowerFlex 755T drives are part of the PowerFlex class of
architecture class drives.
Reference/Feedback The reference is used to send a set point (for example, speed, frequency, or
torque) to the drive. It consists of one 32-bit word of output to the drive from
the network.
Feedback is used to monitor the speed of the drive. It consists of one 32-bit
word of input from the interface to the network.
0 1 2 7 15 23 31
Class C 1 1 0 Network ID Host ID
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