Introduced in 1979 by Schneider Electric (Modicon), the Modbus® fieldbus is an essential, open communication standard, supported by a large number of products and vendors on the market today.
With over 7 million nodes in North America and Europe alone, Modbus is the de facto standard in multi vendor integration.

In a typical Modbus network, messages are sent over an RS232/RS485 serial communication link (EIA standard). The Modbus protocol is based on a master/slave principle, eg. the master sends a request and the addressed slave sends back a response.

As Modbus is a protocol which is independent of the physical network layer, Modbus serial line can be integrated seamlessly into Modbus TCP networks, using simple gateways. This is transparent for the Client application.

Technical characteristics:

Up to 247 devices in one network
Up to 1km network range
Broadcast messaging supported
Standard cabling