Filter
Top Products
3 Basics
3
3.1 Modbus TCP technology
3.1.1 Function principle
Modbus TCP is an Ethernet fieldbus. Modbus TCP describes the
transmission of the Modbus protocol via the Ethernet interface and the
TCP/IP transport and network layers.
The Modbus TCP client (master) connects to the Modbus TCP server
(slave). Once the connection is established, the client sends Modbus
requests to the server. These requests are processed by the server.
The result is returned to the client as a Modbus response.
The Modbus TCP services are identical to the Modbus RTU services.
3.1.2 Bus topology
Star and tree topologies can be used. It is possible to use hubs or
switches. In the case of high bus loads with many devices, it is recom-
mended to use a switches.
The maximum length of a segment is 100 m. A segment consists of
devices and hubs. A network can be subdivided into several segments
by means of gateways or switches. Short cables and a star topology
are recommended to achieve a fast bus cycle.
The transmission rate is 10 or 100 MBit/s in half-duplex mode. If
switches are used, transmission is also possible in full duplex mode.
LXM32M
3 Basics
Modbus-TCP module 15
0198441113843, V1.01, 01.2012