The data values in the DA server are represented as Variant Data type. The COM UA Wrapper converts them to the corresponding OPC UA data type. The mapping is shown in Table A.2:
Table A.2 – DataTypes and mapping
|
Variant Data Type (In DA server) |
OPC UA Data type Mapping in COM UA Server (DataValue structure) |
|
VT_I2 |
Int16 |
|
VT_I4 |
Int32 |
|
VT_R4 |
Float |
|
VT_R8 |
Double |
|
VT_BSTR |
String |
|
VT_BOOL |
Boolean |
|
VT_UI1 |
Byte |
|
VT_I1 |
SByte |
|
VT_UI2 |
UInt16 |
|
VT_UI4 |
UInt32 |
|
VT_I8 |
Int64 |
|
VT_UI8 |
UInt64 |
|
VT_DATE |
Double |
|
VT_DECIMAL |
Decimal |
|
VT_ARRAY |
Array of OPC UA types |
.