The Rheonics SME devices, offer the Modbus TCP service over the Ethernet interface. The Modbus message service provides a Client/Server communication between devices connected on an Ethernet TCP/IP network.  


The SME can be connected through the Ethernet RJ45 connector as part of a network, with intermediary network devices (router, switches) or directly to an Ethernet host in a direct connection.

Figure 1 SME as part of an Ethernet network

Figure 2 Direct connection between SME and ethernet Host


The Rheonics SME device allows the configuration of the Ethernet IP address, mask, gateway and DNS using the RCP software. Please refer to the RCP software manual for instructions on setting these parameters. The factory default values are shown below. 

DHCP = True

IP address=


Gateway =


TCP Port= 502

Slave ID = 255


NOTE: The default TCP Port, and slave ID can’t be modified by the user. 

When DHCP is set to TRUE, the LAN router will automatically assign the IP address to the Sensor SME electronics. This IP address can be found from the RCP (Rheonics Control Panel) communication tab under Ethernet.

To assign fixed IP address, follow the instructions in the RCP manual to set the DHCP to FALSE and assign the IP address, Gateway IP, Subnet mask and DNS IP. 

The IP address assigned to the SME (static or dynamic) is then used by the Modbus Client to access measurements and other diagnostics values from the sensor SME.