EasyUA Reference
HistoryReadAtTime(IList<HistoryReadValueId>,ReadAtTimeDetails,TimestampsToReturn,RequestSettings) Method
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EasyUA Assembly > Advosol.EasyUA Namespace > Session Class > HistoryReadAtTime Method : HistoryReadAtTime(IList<HistoryReadValueId>,ReadAtTimeDetails,TimestampsToReturn,RequestSettings) Method

nodesToRead
List of variable nodes to read data values at specified timestamps from.
details
Configuration parameters for the history read of data at specified timestamps. Configuration parameters include - Array of timestamps for which values are to be read - Flag for bounding value calculation
timestampsToReturn
Enumeration for the timestamps to return with the values. Possible values are source, server or both. The option neither is invalid for history read.
settings
The general settings for the request. If null, the default settings from the property #DefaultRequestSettings are used.

Glossary Item Box

Reads the history of item values synchronously from the OPC server for the given timestamps.

Syntax

Visual Basic (Usage)Copy Code
Dim instance As Session
Dim nodesToRead As IList(Of HistoryReadValueId)
Dim details As ReadAtTimeDetails
Dim timestampsToReturn As TimestampsToReturn
Dim settings As RequestSettings
Dim value As List(Of HistoryDataReadResult)
 
value = instance.HistoryReadAtTime(nodesToRead, details, timestampsToReturn, settings)
C# 
public List<HistoryDataReadResult> HistoryReadAtTime( 
   IList<HistoryReadValueId> nodesToRead,
   ReadAtTimeDetails details,
   TimestampsToReturn timestampsToReturn,
   RequestSettings settings
)

Parameters

nodesToRead
List of variable nodes to read data values at specified timestamps from.
details
Configuration parameters for the history read of data at specified timestamps. Configuration parameters include - Array of timestamps for which values are to be read - Flag for bounding value calculation
timestampsToReturn
Enumeration for the timestamps to return with the values. Possible values are source, server or both. The option neither is invalid for history read.
settings
The general settings for the request. If null, the default settings from the property #DefaultRequestSettings are used.

Return Value

Result data for the requested nodes and time stamps.

Requirements

Target Platforms: Windows 7/8/10, Windows Server 2003/2008/2012/2015, .NET4.x

See Also

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