Annex C DataType (Non-Normative) 
C.1 Mapping of elementary data types 
The mapping of IEC 61131-3 elementary data types to OPC UA data types is formally defined in OPC 30000 (PLCOpen companion specification). Table 74 is copied from that specification as a reference, any differences with OPC 30000 indicate that this specification is out of date.
Table 74 – Mapping IEC 61131-3 elementary data types to OPC UA built in data types
| IEC 61131-3 elementary data types | OPC UA built in data types | Comment |
|---|---|---|
| BOOL | Boolean | A one bit value (true or false). |
| SINT | SByte | An 8 bit signed integer value. |
| USINT | Byte | An 8 bit unsigned integer value. |
| INT | Int16 | A 16 bit signed integer value. |
| UINT | UInt16 | A 16 bit unsigned integer value. |
| DINT | Int32 | A 32 bit signed integer value. |
| UDINT | UInt32 | A 32 bit unsigned integer value. |
| LINT | Int64 | A 64 bit signed integer value. |
| ULINT | UInt64 | A 64 bit unsigned integer value. |
| BYTE | Byte | The PLC open specific OPC UA simple data type BYTE is derived from the built in data type Byte. It describes that the type is used as bit string of length 8. |
| WORD | UInt16 | The PLC open specific OPC UA simple data type WORD is derived from the built in data type UInt16. It describes that the type is used as bit string of length 16 |
| DWORD | UInt32 | The PLC open specific OPC UA simple data type DWORD is derived from the built in data type UInt32. It describes that the type is used as bit string of length 32 |
| LWORD | UInt64 | The PLC open specific OPC UA simple data type LWORD is derived from the built in data type UInt64. It describes that the type is used as bit string of length 64 |
| REAL | Float | OPC UA definition: An IEEE-754 single precision (32 bit) floating point value. IEC 61131-3 definition: Real (32 bit) with a range of values as defined in IEC 60559 for the basic single width floating-point format. Both standards are identical. |
| LREAL | Double | OPC UA definition: An IEEE-754 double precision (64 bit) floating point value. IEC 61131-3 definition: Long real (64 bit) with a range of values as defined in IEC 60559 for the basic double width floating-point format. Both standards are identical. |
| STRING | String | The PLC open specific OPC UA simple data type STRING is derived from the built in data type String. It describes that the type is used as a variable-length single-byte character string. |
| CHAR | Byte | The PLC open specific OPC UA simple data type CHAR is derived from the built in data type Byte. It describes that the type is used as single-byte character |
| WSTRING | String | OPC UA definition: A sequence of UTF8 characters. IEC 61131-3 definition: Variable-length double-byte character string |
| WCHAR | UInt16 | The PLC open specific OPC UA simple data type WCHAR is derived from the built in data type UInt16. It describes that the type is used as double-byte character. |
| DT DATE_AND_TIME | DateTime | OPC UA definition: A 64-bit signed integer which represents the number of 100 nanosecond intervals since January 1, 1601. IEC 61131-3 definition: Date and time of day. |
| DATE | DateTime | The PLC open specific OPC UA simple data type DATE is derived from the built in data type DateTime. It describes that the type is used as a date only. |
| TOD TIME_OF_DAY | DateTime | The PLC open specific OPC UA simple data type TOD is derived from the built in data type DateTime. It describes that the type is used as time of day only. |
| TIME | Double |
The OPC UA simple data type Duration is derived from the built in data type Double. It describes that the type is used as interval of time in milliseconds. |