OPC DA

OPC-клиент подключается к OPC-серверу и коммуницирует с ним через COM-интерфейсы:

Data Access Server Required Interfaces	1.0	2.0	3.0
OPCServer
IUnknown	Required	Required	Required
IOPCServer	Required	Required	Required
IOPCCommon	N/A	Required	Required
IConnectionPointContainer	N/A	Required	Required
IOPCItemProperties	N/A	Required	N/A
IOPCBrowse	N/A	N/A	Required
IOPCServerPublicGroups	Optional	Optional	N/A
IOPCBrowseServerAddressSpace	Optional	Optional	N/A
IOPCItemIO	N/A	N/A	Required
OPCGroup
IUnknown	Required	Required	Required
IOPCItemMgt	Required	Required	Required
IOPCGroupStateMgt	Required	Required	Required
IOPCGroupStateMgt2	N/A	N/A	Required
IOPCPublicGroupStateMgt	Optional	Optional	N/A
IOPCSyncIO	Required	Required	Required
IOPCSyncIO2	N/A	N/A	Required
IOPCAsyncIO	Required	Optional	N/A
IOPCAsyncIO2	N/A	Required	Required
IOPCAsyncIO3	N/A	N/A	Required
IOPCItemDeadbandMgt	N/A	N/A	Required
IOPCItemSamplingMgt	N/A	N/A	Optional
IConnectionPointContainer	N/A	Required	Required
IDataObject	Required	Optional	N/A

Remote

• TCP подключение
• интерфейс IObjectExporter, метод ServerAlive2 – возвращает security bindings сетевых интерфейсов сервера (IP-адреса)
• интерфейс ISystemActivator, метод RemoteCreateInstance
• переход на случайный высокий порт (плохо для брандмауэров)

• метод AlterContext назначает Context ID запрашиваемому интерфейсу
• 0 = QueryInterface, 1=AddRef, 2=Release – унаследованы от IUnknown (?), дальше согласно спецификации
• IOPCServer.AddGroup = Context ID 5, opnum 3

HRESULT AddGroup(
  [in, string] LPCWSTR szName,
  [in] BOOL bActive,
  [in] DWORD dwRequestedUpdateRate,
  [in] OPCHANDLE hClientGroup,
  [unique, in] LONG *pTimeBias,
  [in] FLOAT * pPercentDeadband,
  [in] DWORD dwLCID,
  [out] OPCHANDLE * phServerGroup,
  [out] DWORD *pRevisedUpdateRate,
  [in] REFIID riid,
  [out, iid_is(riid)] LPUNKNOWN * ppUnk
); 

• IOPCBrowse.Browse

HRESULT Browse(
  [in, string] LPWSTR szItemID,
  [in,out, string] LPWSTR *pszContinuationPoint,
  [in] DWORD dwMaxElementsReturned,
  [in] OPCBROWSEFILTER dwBrowseFilter,
  [in, string] LPWSTR szElementNameFilter,
  [in, string] LPWSTR szVendorFilter,
  [in] BOOL bReturnAllProperties,
  [in] BOOL bReturnPropertyValues,
  [in] DWORD dwPropertyCount,
  [in, size_is(dwPropertyCount)] DWORD * pdwPropertyIDs,
  [out] BOOL * pbMoreElements,
  [out] DWORD * pdwCount,
  [out, size_is(,*pdwCount)] OPCBROWSEELEMENT ** ppBrowseElements
);

• IOPCItemMgt.AddItems

HRESULT AddItems(
  [in] DWORD dwCount,
  [in, size_is(dwCount)] OPCITEMDEF * pItemArray,
  [out, size_is(,dwCount)] OPCITEMRESULT ** ppAddResults,
  [out, size_is(,dwCount)] HRESULT ** ppErrors
);

• IOPCSyncIO.Read

HRESULT Read(
  [in] OPCDATASOURCE dwSource,
  [in] DWORD dwCount,
  [in, size_is(dwCount)] OPCHANDLE * phServer,
  [out, size_is(,dwCount)] OPCITEMSTATE ** ppItemValues,
  [out, size_is(,dwCount)] HRESULT ** ppErrors
);

opcda205_cust
OPCDA3.00