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Visual Basic開發BACnet IP主站程序方法介紹
這里要說的方法就是調用BACnet IP主站快速開發工具OMBACnetIPMaster.dll。
步驟1、創建通道，而通道管理所有的Bacnet屬性對象。參數分別IP地址，端口號和網絡超時時間，默認是100毫秒。
Private Sub OpenChannelButton_Click()
StringToByte txtIPAddress, IPAddress()
ChannelHandle(0) = CreateBacnetChannel(IPAddress(0), CLng(txtPort), 100)
End Sub
通道編輯操作的相關API函數聲明如下
‘ 通道管理用于創建、修改、刪除通道。創建通道以后，才能創建Bacnet屬性對象
‘ 創建一個通道對象只要是為了設置不同設備的IP地址和端口號。網絡超時等待時間默認是100毫秒
Function CreateBacnetChannel Lib 'OMBacnetIPMaster.dll' Alias '_CreateChannel@12' (ByRef IPAddress As Byte, ByVal nPort As Long, ByVal nTimeOut As Long) As Long
Function ConfigureChannel Lib 'OMBacnetIPMaster.dll' Alias '_ConfigureChannel@16' (ByVal ChannelHandle As Long, ByRef IPAddress As Byte, ByVal nPort As Long, ByVal nTimeOut As Long) As Long
Function RemoveChannel Lib 'OMBacnetIPMaster.dll' Alias '_RemoveChannel@4' (ByVal ChannelHandle As Long) As Long
步驟2、創建Bacnet屬性對象。
Private Sub CreateBacnetObjButton_Click()
TagHandle(0) = CreateBacnetObj(ChannelHandle(0), 1, 1, 85)
End Sub
BACnet屬性對象編輯相關的API函數申明如下
‘ BACnet對象管理，創建、修改、刪除
‘參數 ChannelHandle 為通道對象的句柄
‘參數 nBacnetObjType 為Bacent屬性對象的類型ID，譬如0表示 Analog Input，1表示Analog Output
‘參數 nInstanceNum 為指明哪一個對象，譬如要訪問Analog Input 1。則 nInstanceNum為1
‘參數 nProperityID 為要訪問屬性的ID，譬如當前值的屬性ID是85
‘參數 TagHandle 為Bacnet對象的句柄
Function CreateBacnetObj Lib 'OMBacnetIPMaster.dll' Alias '_CreateBacnetObject@16' (ByVal ChannelHandle As Long, ByVal nBacnetObjType As Long, ByVal nInstanceNum As Long, ByVal nProperityID As Long) As Long
Function ConfigureObject Lib 'OMBacnetIPMaster.dll' Alias '_ConfigureObject@16' (ByVal ChannelHandle As Long, ByVal nBacnetObjType As Long, ByVal nInstanceNum As Long, ByVal nProperityID As Long) As Long
Function RemoveBacnetObject Lib 'OMBacnetIPMaster.dll' Alias '_RemoveBacnetObject@4' (ByVal TagHandle As Long) As Long
步驟3、BACnet屬性對象的讀寫
Private Sub WriteBacnetObjectButtton_Click()
error = WriteBacnetObj(TagHandle(0), CSng(Tag2.Text), 0)
End Sub
Private Sub ReadBacnetObjButton_Click()
Dim a As Variant
error = ReadBacnetObj(TagHandle(0), a)
Tag1.Text = a
End Sub
‘ BACnet對象屬性值讀寫
‘參數 nTagNum 為Bacnet對象的Tag Number。也就是要寫的對象屬性的數據類型。當操作過ReadBacnet以后，這個參數可以為空。
‘當只寫操作的時候，則需要用戶自己指明是什么數據類型。譬如Analog Output為4.也就是單精度浮點型。
Function ReadBacnetObj Lib 'OMBacnetIPMaster.dll' Alias '_ReadBacnetObject@8' (ByVal TagHandle As Long, ByRef Value As Variant) As Long
Function WriteBacnetObj Lib 'OMBacnetIPMaster.dll' Alias '_WriteBacnetObject@12' (ByVal TagHandle As Long, ByRef Value As Variant, ByVal nTagNum As Long) As Long
步驟4、關閉程序時，釋放對象資源。
Private Sub RemoveBacnetObjButton_Click()
error = RemoveBacnetObject(ByVal TagHandle(0))
End Sub
Private Sub RemoveChannelButton_Click()
error = RemoveChannel(ByVal ChannelHandle(0))
End Sub
最后討論一下輔助函數的作用
‘以下是輔助函數，可以選擇性使用
‘設置寫操作的優先等級
Function SetBacnetPriority Lib 'OMBacnetIPMaster.dll' Alias '_SetBacnetPriority@8' (ByVal TagHandle As Long, ByVal nPriority As Long) As Long
‘返回Bacnet對象屬性的數據類型，一般用于寫操作
Function GetBacnetObjType Lib 'OMBacnetIPMaster.dll' Alias '_GetBacnetObjType@4' (ByVal TagHandle As Long) As Long
‘通信故障狀況回調函數
Function EnableErrorMsgNofity Lib 'OMBacnetIPMaster.dll' Alias '_EnableErrorMsgNofity@4' (ByVal Callback As Long) As Long
Function EnableAbortMsgNofity Lib 'OMBacnetIPMaster.dll' Alias '_EnableAbortMsgNofity@4' (ByVal Callback As Long) As Long
Function EnableRejectMsgNofity Lib 'OMBacnetIPMaster.dll' Alias '_EnableRejectMsgNofity@4' (ByVal Callback As Long) As Long
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