User Manual

6 ADAM-4572 User's Manual
1.2.4 Modbus/TCP
As a new extension of Modbus/RTU, the Modbus/TCP protocol defines
how Modbus/RTU messages are encoded within and transported over
TCP/IP-based networks. Modbus/TCP is just as simple to implement and
flexible to apply as the original Modbus/RTU. The Modbus/TCP proto-
col is defined by its form of encapsulation for a Modbus request or
response. That means the Modbus request or response data is encapsu-
lated in TCP frame that has a six-byte header in Modbus/TCP protocol.
Modbus/TCP enables the use of Modbus messaging in an Intranet run-
ning the TCP/IP protocols. Modbus/TCP is most commonly used for
Ethernet attachment of PLC’s or I/O modules to other simple field buses
or I/O networks.