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The OPC client can be constructed even with the custom application named VB, EXCEL, and VC. In general, the custom interface (custom I/F and abbreviation thereafter) is used in the automation interface (automation I/F and abbreviation thereafter) and VC++ when constructing it with VBA of VB6 and EXCEL. And,In the NET environment. Custom I/F can be referred to by using NET rapper (RCW).
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Commentor / M.Ike |
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Easy to develop the dot net client |
It was a long way in it until special knowledge like the type conversion, the Marcia ring, and the memory management, etc. the client construction with .NET environment to connect it with .NET rapper was necessary, and the OPC connection succeeded. To begin with, being not able to use a past automation rapper (DAAUTO rapper thereafter) with VB.NET was the maximum problem.
There might be a person who feels irrationality that should make the application from one again strongly because the reference library is uncorrespondence though the source is Apparcompati though VB6 becomes unavailable and it often hears of the case that shifts to VB.NET, too.
A new DAAUTO wrapper was released by the OPC conference in April, in such and 2004. The maximum improvement of this wrapper. Use in the NET environment became possible. It came to be able to do the shift from VB6 to VB.NET by this easily at last.
Then, the note when the up-grade is done from VB6 to VB.NET is described as follows. This content applies when the application is newly constructed with VB.NET.
1. The cardinal number of the array is "0" fixation in .NET though the DAAUTO wrapper treats the cardinal number of the array as one. Therefore, when the element of the array argument used by the OPC function is read and written, element 0 is not used, and it begins from element 1.
MyOPCItems.AddItems(iItemNum, sItemNames, iClientHandles, iServerHandles, iErrors)
For i = 1 To iItemNum
m_iErrors(i) = iErrors(i)
Next i
2. The OPCServer instance is not liberated only by liberating the OPCServer object. OPCServer ends by the garbage collect.
MyOPCServer = Nothing : The instance is not liberated only by liberating the object.
System.GC.Collect() : The instance is releaseed to do the garbage collect
3. The array argument of the Output type used by the OPC function is defined by the Array type.
Dim iErrors() As Integer
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Dim iErrors() As Array
Dim iServerHandles() As Integer
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Dim iServerHandles As Array
It came to be able to construct the OPC client with VB.NET easily by the new DAAUTO rapper though it overlapped. Especially, it will be able to be said the maximum good news for the VB6 user.
However, the DAAUTO rapper doesn't support OPCDA3.0. This cannot be used with the DAAUTO rapper though the OPCItemIO interface added with OPCDA3.0 is a function convenient to read and write data by the one shot. One sideThe NET rapper supports all interfaces of OPCDA3.0. With the DAAUTO rapper according to the situation. How if the NET rapper is used properly.
The new DAAUTO wrapper is attached to Ver3.01 Build1 made of our company OPC Server and the product since Ver2.42 Build9 and try by all means, please.
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Inside MELSEC
Advanced OPC