VWE generates OPC items (CallR server)
Determines the CallR capability of the OPC server. The following categorisation must be observed when dealing with OPC servers: During initialisation, the OPC server reads its process variable definitions (ItemID, address in the PLC, data type, etc.) from a specific source (project file). A client that wants to exchange process variables with the OPC server must register this by transferring the ItemID. This specification is fulfilled by all OPC servers.
CallR servers also enable the dynamic generation of process variable definitions in the OPC server, i.e. a client can transmit a process variable definition to the OPC server at runtime. The OPC server saves the new process variable definition. The data exchange between the OPC server and the PLC is started on request from the client.
VisiWin supports the two categories in the following form:
OPC servers with their own project file can be read out using the browse function in the editor. The process variable definitions required in the application are mirrored from the OPC server project to the VisiWin project file. On request from an application, the variable server sends the ItemID to the OPC server and registers the data transfer.
In addition, process variable definitions can be created in the editor itself. These are then sent to the OPC server at runtime.
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Setting |
Description of the |
|---|---|
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Active |
The communication component is treated as a CallR server. During initialisation, all process variable definitions from the VisiWin project file are sent to the OPC server. |
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Inactive |
The ItemID values of the process variable definitions are sent to the communication component as an identifier when a data exchange is requested by a client application. |