Technical data

Fieldbus Communication • 175
ETHERNET
WAGO-I/O-SYSTEM 750
BACnet/IP Controller
data and the resultant increase in processing speed.
Many programs use both protocols. Important status information is
sent via the reliable TCP connection, while the main stream of data
is sent via UDP.
(3)
TCP, UDP
(2)
IP
(1)
ETHERNET
(physical interface, CSMA/CD)
(4) Management, Diagnostic and Application Protocols:
Positioned above the TCP/IP stack or UDP/IP layer are correspondingly im-
plemented management, diagnostic and application protocols that provide ser-
vices that are appropriate for the application. For the management and diag-
nostic, these are, for example, SMTP (Simple Mail Transport Protocol) for e-
mails, HTTP (Hypertext Transport Protocol) for www browsers and some oth-
ers.
In this example, the protocols MODBUS/TCP (UDP) and EtherNet/IP are im-
plemented for use in industrial data communication.
Here the MODBUS protocol is also positioned directly above TCP (UDP)/IP;
EtherNet/IP, on the other hand, basically consists of the protocol layers
ETHERNET, TCP and IP with an encapsulation protocol positioned above it.
This serves as interface to CIP (Control and Information Protocol).
DeviceNet uses CIP in the same way as EtherNet/IP. Applications with De-
viceNet device profiles can therefore be very simply transferred to
EtherNet/IP.
Application device profiles
(e.g. positioning controllers, semi-
conductors, pneumatic valves)
CIP application objects library
CIP data management services
(explicit messages, I/O messages)
Mail client
WWW browser
...
CIP message routing, connection
management
CIP
(4)
SMTP
HTTP
...
MODBUS
Encapsulation
protocol
(3)
TCP, UDP
(2)
IP
(1)
ETHERNET
(physical interface, CSMA/CD)
ETHERNET/IP