Some advanced drivers support eavesdropping. The eavesdropping feature is designed to allow a new system to run in parallel to an existing system. This means that you can Test the Configuration of a New System with almost no risk to the operation of the outstations.
Eavesdropping works by allowing an existing system to maintain control of the outstations, while a new server processes the data that the outstations report to ClearSCADA.
The existing system communicates with the outstations via one or more channels. Each channel consists of a receive line (Rx) and a transmit line (Tx)—the Rx line at the ClearSCADA server connection is the Tx line at the outstation connection (the ClearSCADA server receives the data that is transmitted from the outstations).
Special serial cables are used to connect the new server to the line(s) at the existing server’s connection. The eavesdropping arrangement differs, depending on the drivers that are used on your system. Each type of driver requires one of these arrangements:
Refer to the relevant driver guide for information on which arrangement is required by that particular protocol.