system.opchda.readAttributes
This function is used in Python Scripting.
Description
Reads the specified attributes for the given item over a time range. Attributes and their IDs are defined in the OPC-HDA specification, and can be discovered by calling system.opchda.getAttributes().
Client Permission Restrictions
This scripting function has no Client Permission restrictions.
Syntax
system.opchda.readAttributes(serverName, itemId, attributeIds, startDate, endDate)
Parameters
| Type | Parameter | Description |
|---|---|---|
| String | serverName | The name of the defined OPC-HDA server to read. |
| String | itemId | The itemID to retrieve attributes for. |
| String | attributeIds | The integer IDs of the attributes to read. The attribute ids are defined in the OPC-HDA specification. The attributes can also be obtained by calling system.opchda.getAttributes(). Some servers may not support all attributes. |
| String | startDate | The starting date/time of the query. |
| String | endDate | The ending date/time of the query. |
Returns
ReadResults[] - A list of read results which is one-to-one with the requested attributes. The ReadResult object has a serviceResult quality property that indicates whether the call was successful, and is itself a list of QualifiedValues.
Scope
All