The EtherModbus gateway allows serial Modbus RTUs to communicate and interoperate with Modbus/TCP based controllers. The Modbus standard protocol is an asynchronous protocol designed to connect directly to computer asynchronous ports. Modbus has been extended to operate over ethernet using the IP protocol suite. This gateway converts between the Modbus TCP/IP protocol and Modbus ASCII/RTU protocols transparently. The EMB-02 enables one or more MODBUS controllers to communicate with MODBUS ASCII/RTU based serial RTUs. It will not allow Modbus/TCP RTUs to operate with a serial MODBUS controller.
The Ethernet Modbus gateway contains two independent serial ports. Each may be configured as RS-232, RS-422, or RS-485 (2 or 4 wire). When configured for RS-485 4-wire, multiple RTU polling strings may be polled on each interface.
A companion product, the EtherPollis appropriate for applications using other protocols. The EtherPollis protocol independent, and requires no knowledge of the RTU protocol. This allows it to work with any asynchronous byte-oriented protocol with no additional configuration. The EtherPoll uses UDP/IP. It's data sheet is here.
The EtherGate is another companion product that is protocol-aware. It enables serial SCADA devices to communicate via an ethernet network. The EtherGate is ideal for transporting SCADA protocols via ethernet.
To transport SCADA protocols over Frame Relay circuits (without ethernet), use the DCB BPF Scada-FRAD.