C++ Based OPC UA Client/Server/PubSub SDK
1.7.8.584
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Selects a set of raw or interpolated values from the history database by specifying a series of timestamps for one or more variables. More...
#include <opcua_types.h>
Public Attributes | |
OpcUa_DateTime * | ReqTimes |
Defines the specific timestamps for which values are to be read. | |
OpcUa_Boolean | UseSimpleBounds |
Use simple bounds to determine the value at the specific timestamp. | |
Selects a set of raw or interpolated values from the history database by specifying a series of timestamps for one or more variables.
The ReadAtTimeDetails structure reads the values and qualities from the history database for the specified timestamps for one or more HistoricalDataNodes. This function is intended to provide values to correlate with other values with a known timestamp. For example, a Client may need to read the values of sensors when lab samples were collected.
The order of the values and qualities returned shall match the order of the timestamps supplied in the request.
If no value exists for a specified timestamp, a value shall be interpolated from the surrounding values to represent the value at the specified timestamp. The interpolation will follow the same rules as the standard interpolated aggregate as outlined in Part 13 of the OPC UA specification.
If the useSimpleBounds flag is True and interpolation is required, SimpleBounds will be used to calculate the data value.
If a value is found for the specified timestamp, the server will set the StatusCode InfoBits to be Raw. If the value is interpolated from the surrounding values, the server will set the StatusCode InfoBits to be Interpolated.
If the requested timestamp format is not supported for a node, the operation shall return the Bad_TimestampNotSupported StatusCode.