Difference between revisions of "Activity:AccessOPCUAVariable (Activity)"
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Revision as of 10:24, 4 March 2015
The AccessOPCUAVariable reads or writes a single OPC UA Variable that was previously configured within an OPC Connection.
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Description
| Configure OPC UA Variable | |
|---|---|
| Name | AccessOPCUAVariable |
| Purpose | Read or write a single OPC UA variable |
| Category | UBIK OPC UA Interface |
| Returns | True if successful |
| Version | 2.4.1+ |
Arguments
| Argument | Type | Direction | Purpose |
|---|---|---|---|
| Variable | OpcUaVariable | In | The variable to read or write as produced by a Scope activity. |
| Value | Object | InOut | The value to write to the variable. If null, the variable will be read. |
| Connection | OpcUaServerConnection | In | If the activity is not embedded with an Scope activity, a valid connection has to be specified. |
| Quality | OpcUaQuality | Out | The quality of the accessed value as delivered by the OPC source |
| Result | Boolean | Out | True if successful, false if failed |
Usage
This activity is used to read or write a value of a single OPC variable within an OPC Scope. if Value is supplied with null, it will read the value of the variable. If Value is supplied with something else than null, it will attempt to write it to the variable. If it is used outside of a scope activity, it has to be supplied with a valid OPC connection object as produced by an OPC connection somewhere else in the workflow.
Example
The CreateOPCUAScope activity, as used in the larger example "Read value from OPC variable":
