Rockwell Automation Ethernet Design Considerations Reference Manual - Manual (Page 59)

Rockwell Automation Publication ENET-RM002C-EN-P - May 2013 59
Chapter
4
EtherNet/IP Protocol
The EtherNet/IP protocol is standard Ethernet and standard IP technologies
with standard CIP technology at the application layer.
Connections EtherNet/IP communication modules must consider connections and EtherNet
nodes to communicate on the EtherNet/IP network. The number of supported
nodes applies only to CompactLogix 5370 controllers. See
page 65 .
A connection is a point-to-point communication mechanism used to transfer
data between a transmitter and a receiver. Connections can be logical or physical.
Two connection types--TCP connections and CIP connections--are layered over
each other each time data is transferred. The TCP connection is the first
connection established. It is used for all EtherNet/IP communication and is
required for all CIP connection use. A single TCP connection supports multiple
CIP connections and remains open.
Established over TCP connections, EtherNet/IP CIP connections transfer data
from an application running on one end-node (transmitter) to an application
running on another end-node (receiver). CIP connections are configured to use
explicit or implicit message types. The message types support connected and
unconnected connection types. Typically, connected CIP messages are used to
transfer data. Unconnected CIP messages are used, but they are only temporary.
Topic Page
Connections 59
EtherNet/IP Network Specifications 66
Packets Rate Capacity 69
Requested Packet Interval (RPI) 70
Messaging 71
CIP Safety 73
CIP Sync 74
Integrated Motion on an EtherNet/IP Network 76
Connectivity to IT 77