Thursday, May 25, 2017 Useful Resources for Industrial Technology Enthusiasts!


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Asynchronous

  • OPC I/O Servers supports two different methods of obtaining data: Synchronous and Asynchronous I/O.


  • In typical OPC client, this selection updates items at regular intervals.


  • Asynchronous I/O, by comparison, does not enable the OPC Client to poll the server; it provides data between the driver and the OPC server on an exception basis.

  • Using Asynchronous I/O, the server notifies the OPC Client when data has exceeded the user-supplied percent deadband.

  • This architecture offers low communications overhead because the driver does not repeatedly poll for the same data over and over again.

  • Information that is not synchronized to a continuously running clock. With asynchronous transmission, each character begins with a 'start' bit and ends with a 'stop' bit and the clock is only synchronized for the duration of the character.


  • See also Synchronous.




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