DataObject
DataObject items maps to IEC61850 concept of DataObjects on the server, where each DataObject has a set of functionally constrained (FC) data attributes.
The item type has the following properties:
| Name | Description | ID | Flags |
|---|---|---|---|
| Scale | Will scale the value according to y=ax+b, where a=scale | 5005 | Persisted |
| Offset | Will scale the value according to y=ax+b, where b=offset | 5006 | Persisted |
| SrcItmID | Data reference to the DataObject, usually on the form LDName/LNodeName.Object [string] | 5030 | Persisted |
| Functional contraint | Functional constraint of the data object | 17001 | Persisted |
| V | Data Attribute (DA) used for item value [string] | 17003 | Persisted |
| Q | Data attribute (DA) used for item quality [string] | 17004 | Persisted |
| T | Data attribute (DA) used for item time [string] | 17005 | Persisted |
| Attributes | Available data attributes on the data object | 17002 | ReadOnly |
| IEC Quality | The IEC61850 specific quality of last received value | 17006 | ReadOnly |
For scalar DataObjects, VQT attributes can be flat, e.g. v or nested structures e.g. level1.level2.v.
In the case where DataObject is an array, the items in the array can be accessed with
- SrcItmID = LDName/LNodeName.arrayObject(0) and VQT attributes = myStruct.myVal
- SrcItmID = LDName/LNodeName.arrayObject and VQT attributes = (0).myStruct.myVal.
The (1) method is prefered if the VQT values are located in the same index, otherwise (2) can be used but will be more inefficient as it will read the whole array.
All available VQT attributes are listed in the Attributes attribute of the item.
Note regarding VQT attributes:
- V is mandatory and must match an item in the the available data attributes.
- Q and T is optional, but if set must match a an item in the available data attributes. They must also match with the expected type, which for Q is a bitstring and T is a utc-time. If not set, the default values of good quality and current time is used. Failing to satisfy these requirements will result in a config error quality on the item.
Notes regarding Quality:
- Apis will set the item qualities to NOT_CONNECTED if it client looses connection to the server.
- Apis will set the item qualities to CONFIG_ERROR if srcItemID or VQT attributes are invalid.
- Apis will set the item qualities to COMM_ERROR if reading invalid/error data from the server.