Modbus protocol is an industry-wide serial communications standard supported by many PLC and industrial controls manufacturers. There are two serial Modbus protocols: Modbus RTU and Modbus ASCII. Both protocols can be recognized by most SIXNET stations and I/O modules over their serial port(s).
There are two Open Modbus protocols for Ethernet communication: Modbus/UDP and Modbus/TCP. Both protocols can be recognized by SIXNET stations and I/O modules that have Ethernet port(s).
For more information on Modbus protocol refer to the Modicon Modbus Protocol Reference Guide, available from Modicon.
Related Topics: Modbus Support in SIXNET I/O
Modbus/TCP (Open Modbus) over Ethernet
Modbus Commands Supported by SIXNET
Modbus Addressing Versus SIXNET Addressing
Reading and Writing Long Integer and Floating Point Values