To provide a communication station in which communication with a PLC is universally made via an OPC server, data on the PLC can be treated in a way similar to a general tag access from an outer computer through a control bus and only changed data can be reflected on the PLC when data that are set from the outer computer to the PLC are changed.

The OPC communication station is interposed between the OPC server to which the PLC is connected and an outside computer, and operates on a general-purpose personal computer. The station is provided with a means communicating with PLC via the OPC server, a means communicating with the outside computer through the control bus, a means accessing data of the PLC as a tag, a means monitoring data of the PLC, a communication input/output means storing data collected from the PLC and data which are set in the PLC, a data collecting means setting data on the PLC in the communication input/output means via the OPC server and a data writing means giving a writing request of changed data in writing data in the communication input/output means to the OPC server.

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