class QOpcUaHistoryReadEventRequest

This class stores the necessary information to request historic data from a server. More…

Added in version 6.7.

Synopsis

Methods

Note

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Detailed Description

This is the Qt OPC UA representation for the OPC UA ReadEventDetails for reading historical data defined in OPC-UA part 11, 6.4.2 .

When requesting historic data from a server, several values need to be provided to the server to know which data to collect. The QOpcUaHistoryReadEventRequest class provides the required values. startTimestamp and endTimestamp define the timerange where historic events should be collected from. nodesToRead defines from which nodes historic data should be collected. numValuesPerNode defines the maximum number of events that should be returned per node. filter is the event filter used to determine which events and which of their fields to return.

__init__()

Constructs an invalid QOpcUaHistoryReadEventRequest .

__init__(other)
Parameters:

other – QOpcUaHistoryReadEventRequest

Constructs a QOpcUaHistoryReadEventRequest item from other.

__init__(nodesToRead, startTimestamp, endTimestamp, filter)
Parameters:

  • nodesToRead – .list of QOpcUaReadItem

  • startTimestamp – QDateTime

  • endTimestamp – QDateTime

  • filter – EventFilter

Constructs a QOpcUaHistoryReadEventRequest item with the given values.

addNodeToRead(nodeToRead)
Parameters:

nodeToRead – QOpcUaReadItem

Adds a node to the nodeToRead list.

endTimestamp()
Return type:

QDateTime

Returns the end time stamp.

filter()
Return type:

EventFilter

Returns the event filter used to retrieve historical events.

See also

setFilter()

nodesToRead()
Return type:

.list of QOpcUaReadItem

Returns the list of nodes to read.

See also

setNodesToRead()

numValuesPerNode()
Return type:

int

Returns the number of values per node.

__ne__(rhs)
Parameters:

rhs – QOpcUaHistoryReadEventRequest

Return type:

bool

Returns true if lhs is not equal to rhs; otherwise returns false.

Two QOpcUaHistoryReadEventRequest items are considered not equal if their startTimestamp, endTimestamp, numValuesPerNode, filter or nodesToRead are not equal.

__eq__(rhs)
Parameters:

rhs – QOpcUaHistoryReadEventRequest

Return type:

bool

Returns true if lhs is equal to rhs; otherwise returns false.

Two QOpcUaHistoryReadEventRequest items are considered equal if their startTimestamp, endTimestamp, numValuesPerNode, filter and nodesToRead are equal.

setEndTimestamp(endTimestamp)
Parameters:

endTimestamp – QDateTime

Sets endTimestamp for the historical data to be fetched.

See also

endTimestamp()

setFilter(filter)
Parameters:

filter – EventFilter

Sets the event filter used to retrieve historical events to filter.

See also

filter()

setNodesToRead(nodesToRead)
Parameters:

nodesToRead – .list of QOpcUaReadItem

Sets the nodesToRead list.

See also

nodesToRead()

setNumValuesPerNode(numValuesPerNode)
Parameters:

numValuesPerNode – int

Sets numValuesPerNode to indicate the number of values per node to be fetched.

setStartTimestamp(startTimestamp)
Parameters:

startTimestamp – QDateTime

Sets startTimestamp for the historical data to be fetched.

See also

startTimestamp()

startTimestamp()
Return type:

QDateTime

Returns the start time stamp.

swap(other)
Parameters:

other – QOpcUaHistoryReadEventRequest

Swaps read event request object other with this read event request object. This operation is very fast and never fails.