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Thread: Less variables on the standby server

  1. #1
    Join Date
    13.03.2008
    Posts
    8

    Default Less variables on the standby server

    Hi,

    Please assume a project with 2000 variables, Modbus driver, a server, a standby server, 2 x clients.

    It is a Telemetry project and the standby server is in the control center room, far from the server.

    How is it possible, not to receive all the variables values of the server on the standby server.
    For example we have 2000 variables on the server but we just want to get 1000 of them on the St. Server. This will reduce the data traffic.

    Thanks and waiting for your reply.

  2. #2

    Default Re: Less variables on the standby server

    The principle of seamless redundancy is, that both the server and the standby server are running a driver and are communicating to the hardware.

    The server and the standby server, both run exactly the same copy. When the server fails, the standby server takes over the server role without data loss. Any clients in the project would automatically connect to the standby server, which is now running as the server for this project.

    The communication between the server and the standby server is very minimalistic and highly optimized. The server only reports value changes to the standby server for those variables that are requested by the standby server.

    For example those variables that are shown in a screen on the standby server itself. This is the same as the communication between the server and a client.

    If you want to reduce this even further, you can open a screen on the standby server, that shows no variables at all, but I think you will find that the network traffic is very low anyway.

    All other variables that the standby server needs to guarantee a seamless redundancy without data loss, is retrieved by the driver on the standby server directly from the PLC hardware.

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