DataType

Client item's data type

Description

DataType indicates the data type of the item as stored in the daitem object in the MATLAB^® workspace. You can specify the data type when the item is created using the additem function. If you do not specify a data type, or if the requested data type is rejected by the server, the canonical (native) data type is used. If the client associated with the item is not connected, the data type is set to 'unknown' until the client is connected.

The OPC server uses this data type to store the item value. The CanonicalDataType property of a daitem object provides information on the canonical data type of that item on the server.

OPC communication uses COM Variant data types to send information between the server and client. These are automatically translated to an equivalent MATLAB data type for the COM Variant types defined below. Any data type not included in this list is returned as 'unknown'.

OPC Toolbox™ Data Type	COM Data Type	MATLAB Data Type
double	VT_R8	double
char	VT_BSTR	char
single	VT_R4	single
uint8	VT_UI1	uint8
uint16	VT_UI2	uint16
uint32	VT_UI4	uint32
uint64	VT_UI8	uint64
int8	VT_I1	int8
int16	VT_I2	int16
int32	VT_I4	int32
int64	VT_I8	int64
currency	VT_CY	double
date	VT_DATE	double
logical	VT_BOOL	logical
double	VT_EMPTY	Empty array ([])

Characteristics

Access	Read-only while logging
Applies to	daitem
Data type	character vector
Values	[{'unknown'} | 'double' | 'char' | 'single' | 'uint8' | 'uint16' | 'uint32' | 'uint64' | 'int8' | 'int16' | 'int32' | 'int64' | 'currency' | 'date' | 'logical']