Rockwell Automation 20-COMM-E PowerFlex EtherNet/IP Adapter User Manual
Page 288
G-8
Glossary
20-COMM-E EtherNet/IP Adapter User Manual
Publication 20COMM-UM010G-EN-P
For example, a subnet mask on a network may appear as follows: 11111111
11111111 11111111 11000000 (255.255.255.192). This mask indicates that
26 bits are used to identify the network and 6 bits are used to identify
devices on each network. Instead of a single physical Class C network with
254 devices, this subnet mask divides it into four networks with up to 62
devices each.
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.
T
TCP (Transmission Control Protocol)
EtherNet/IP uses this protocol to transfer Explicit Messaging packets using
IP. TCP guarantees delivery of data through the use of retries.
U
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 verifies 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 for written
and read values to correctly display them in human readable format).
Update
The process of updating firmware in a device. The adapter and its connected
PowerFlex 7-Class host drive and its peripherals can be updated using
various Allen-Bradley software tools. See
Z
Zero Data
When communication is 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.