Rockwell Automation 20-750-ENETR PowerFlexDual-Port EtherNet/IP Option Module - Manual (Page 194)

194 Rockwell Automation Publication 750COM-UM008A-EN-P - July 2012
Glossary
Status Indicators Status indicators are LEDs that are used to report the status of the option
module, network, and drive. They are on the option module and can be viewed
when the drive is powered and its cover is removed.
Stop Action When communication is disrupted (for example, a cable is disconnected), the
option module and drive can respond with a stop action. A stop action 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 option module, it
will stay running but at zero Reference.
Subnet Mask An extension to the IP addressing scheme that lets you use a single network ID
for multiple physical networks. A bit mask identifies the part of the address that
specifies the network and the part of the address that specifies the unique node
on the network. A “1” in the subnet mask indicates the bit is used to specify the
network. A “0” in the subnet mask indicates that the bit is used to specify the
node.
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.
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.
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 option modules 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 option module can be updated
using various Allen-Bradley software tools. See
Updating the Option Module
Firmware on page 52 for more information.
Zero Data When communication is disrupted (for example, a cable is disconnected), the
option module 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 option module, it will
stay running but at zero Reference.