Data Types
- Last UpdatedJul 07, 2025
- 1 minute read
OPC servers can provide data in different data formats. An OPC client can request data in a specific format or use the server’s type (that is, the type in which the data is stored within the server).
When specifying a data type, consider whether the server will be able to convert data to the requested type.
Use the table below to help you specify a type for a variable tag. It shows mappings from the types used by OPC (VARTYPE) to Plant SCADA data types. If followed, these data types coerce the OPC data Plant SCADA data types.
|
OPC Type (VARTYPE) |
Description |
Plant SCADA Data Type |
|
VT_BOOL |
Boolean |
DIGITAL |
|
VT_UI1 |
Byte |
BYTE |
|
VT_I2 |
2 byte integer |
INT |
|
VT_UI2 |
2 byte unsigned integer |
UINT |
|
VT_I4 |
4 byte integer |
LONG |
|
VT_U14 |
4 byte unsigned integer |
ULONG (requires v7.0) |
|
VT_CY |
Currency |
STRING |
|
VT_R4 |
4 byte real |
REAL |
|
VT_R8 |
8 byte real |
STRING |
|
VT_DATE |
Date |
STRING |
|
VT_BSTR |
String |
STRING |
|
VT_ERROR |
Error value |
LONG |
|
VT_QUALITY |
2 byte integer |
INT |
|
VT_TIMESTAMP |
4 byte integer |
LONG |
|
VT_MILLISECOND |
4 byte integer |
LONG |