DAVtq Class

Holds data value, timestamp and quality, abbreviated sometimes as VTQ. This is a common combination in OPC, e.g. returned when an OPC item is read.

Object Model

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ComDefaultInterfaceAttribute(OpcLabs.EasyOpc.DataAccess.ComTypes._DAVtq)>
<ComVisibleAttribute(True)>
<GuidAttribute("FAA7B8BC-82B6-4BC7-AB7B-C3671D622DE0")>
<TypeConverterAttribute(System.ComponentModel.ExpandableObjectConverter)>
<CLSCompliantAttribute(True)>
<ValueControlAttribute("OpcLabs.BaseLib.Forms.Common.ObjectSerializationControl, OpcLabs.BaseLibForms, Version=5.81.455.1, Culture=neutral, PublicKeyToken=6faddca41dacb409", 
   DefaultReadWrite=False, 
   Export=True, 
   PageId=10001)>
<SerializableAttribute()>
Public Class DAVtq 
   Inherits OpcLabs.BaseLib.Info
   Implements LINQPad.ICustomMemberProvider, OpcLabs.BaseLib.ComTypes._Info, OpcLabs.BaseLib.ComTypes._Object2, OpcLabs.EasyOpc.DataAccess.ComTypes._DAVtq, System.ICloneable, System.IFormattable, System.Runtime.Serialization.ISerializable, System.Xml.Serialization.IXmlSerializable

'Usage
 
Dim instance As DAVtq

[ComDefaultInterface(OpcLabs.EasyOpc.DataAccess.ComTypes._DAVtq)]
[ComVisible(true)]
[Guid("FAA7B8BC-82B6-4BC7-AB7B-C3671D622DE0")]
[TypeConverter(System.ComponentModel.ExpandableObjectConverter)]
[CLSCompliant(true)]
[ValueControl("OpcLabs.BaseLib.Forms.Common.ObjectSerializationControl, OpcLabs.BaseLibForms, Version=5.81.455.1, Culture=neutral, PublicKeyToken=6faddca41dacb409", 
   DefaultReadWrite=false, 
   Export=true, 
   PageId=10001)]
[Serializable()]
public class DAVtq : OpcLabs.BaseLib.Info, LINQPad.ICustomMemberProvider, OpcLabs.BaseLib.ComTypes._Info, OpcLabs.BaseLib.ComTypes._Object2, OpcLabs.EasyOpc.DataAccess.ComTypes._DAVtq, System.ICloneable, System.IFormattable, System.Runtime.Serialization.ISerializable, System.Xml.Serialization.IXmlSerializable

[ComDefaultInterface(OpcLabs.EasyOpc.DataAccess.ComTypes._DAVtq)]
[ComVisible(true)]
[Guid("FAA7B8BC-82B6-4BC7-AB7B-C3671D622DE0")]
[TypeConverter(System.ComponentModel.ExpandableObjectConverter)]
[CLSCompliant(true)]
[ValueControl("OpcLabs.BaseLib.Forms.Common.ObjectSerializationControl, OpcLabs.BaseLibForms, Version=5.81.455.1, Culture=neutral, PublicKeyToken=6faddca41dacb409", 
   DefaultReadWrite=false, 
   Export=true, 
   PageId=10001)]
[Serializable()]
public ref class DAVtq : public OpcLabs.BaseLib.Info, LINQPad.ICustomMemberProvider, OpcLabs.BaseLib.ComTypes._Info, OpcLabs.BaseLib.ComTypes._Object2, OpcLabs.EasyOpc.DataAccess.ComTypes._DAVtq, System.ICloneable, System.IFormattable, System.Runtime.Serialization.ISerializable, System.Xml.Serialization.IXmlSerializable

Remarks

The DAVtq class is a fundamental part of the OPC Data Access support, providing a standardized way to represent the data collected from or written to an OPC server. Each instance of DAVtq contains:

A data value, which can be of any type, representing the current value of an OPC item.
A quality status, indicating the reliability or validity of the data value.
A timestamp, marking the time at which the data value was read from or written to the server.

Inheritance Hierarchy

System.Object
   OpcLabs.BaseLib.Object2
      OpcLabs.BaseLib.Info
         OpcLabs.EasyOpc.DataAccess.DAVtq
            OpcLabs.EasyOpc.DataAccess.Generic.DAVtq<TValue>

Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

Reference

DAVtq Members
OpcLabs.EasyOpc.DataAccess Namespace

Documentation Home, Send Feedback. Resources: Knowledge Base, Product Downloads. Technical support: Online Forums, FAQ.

Missing some example? Ask us for it on our Online Forums! You do not have to own a commercial license in order to use Online Forums, and we reply to every post.