Information status: Updated
- The OPCaccess class maps data items from an OPC server to Tango
attributes. For every OPCaccess device the attibute data type has to be specified. Tango can handle only double, long and short attributes. All OPC data items are casted to the requested data type. If an OPC item is an array (uses the ,lxx) extension in the item name, the tango attribute is created as a spectrum attibute.
For OPC servers which cannot handle array types, the property "array_handling" must be set to false to trigger correct data conversion.
|Triggers reading of data directly from the OPC item.|
|Triggers reading of data from the OPC data cache.|
|This command gets the device status (stored in its device_status data member) and returns it to the caller.|
|This command gets the device state (stored in its device_state data member) and returns it to the caller.|
|Array_handlingDevString||Specifies whether the OPC server used is capable to handle arrays or only scalar data types. array_handling = ``true`` , array data types are handled. array_handling = ``false``, only scalar data types are handled.|
|Data_typeDevString||This is set as the requested data type for the OPC items to be read. The possible data types are ``double``, ``long`` or ``short``.|
|Item_namesStringType||Specifies the OPC item names to be read from the OPC server via the given path.|
|Path_nameDevString||Specifies the path of the OPC item to be addressed on the OPC server.|
|Server_nameDevString||Specifies the name of the OPC server to be used.|
|DataFromCacheDevShort||Triggers data reading from the OPC cache or directly from the OPC item. Set to 1 -> cache reading is enabled. Set to 0 -> direct access is enabled.|
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