OPC - OLE (Object Linking and Embedding) for Process Control :: The Industrial Interoperability Standard
Asynchronous Knowledge Base
most important key terminologies you need to know if you work in Automation, Controls, Brilliant Manufacturing, Operational & Industrial Intelligence or IoT etc.
; regardless of any vendor(s) you are dealing (Allen Bradley, GE Fanuc, Siemens, Modicon, Mitsubishi, Omron, Automation Direct etc).
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.
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