Rockwell Automation 25B PowerFlex 525 Embedded EtherNet/IP Adapter - Manual (Page 162)

162 Rockwell Automation Publication 520COM-UM001B-EN-E - March 2013
Glossary
Switches Network devices that provide virtual connections that help to control collisions
and reduce traffic on the network. They are able to reduce network congestion by
transmitting packets to an individual port only if they are destined for the
connected device. In a control application, in which real time data access is
critical, network switches may be required in place of hubs.
TCP (Transmission Control Proto-
col)
EtherNet/IP uses this protocol to transfer Explicit Messaging packets using IP.
TCP guarantees delivery of data through the use of retries.
UDP (User Datagram Protocol) EtherNet/IP uses this protocol to transfer I/O packets using IP. UDP provides a
simple, but fast capability to send I/O messaging packets between devices. This
protocol ensures that adapters transmit the most recent data because it does not
use acknowledgements or retries.
UDDT (User-Defined Data Type) A structure data type that you define during the development of an application
(for example, to convert 32-bit REAL parameter data to correctly write and read
their values).
Zero Data When communications are disrupted (for example, a cable is disconnected), the
adapter and drive can respond with zero data. Zero data results in the drive
receiving zero as values for Logic Command, Reference, and Datalink data. If the
drive was running and using the Reference from the adapter, it will stay running
but at zero Reference.