Data types
- Last UpdatedApr 24, 2025
- 1 minute read
The Open Platform Communications (OPC) client protocol supports seven different data types and supports conversion between different data types.
The following table lists the data types supported by the OPC client protocol:
|
OPC Client protocol data type |
Database |
|||
|---|---|---|---|---|
|
Analog |
Status |
Rate |
Multistate (Bit Format) |
|
|
Boolean |
N/A |
Read/Write |
N/A |
Read/Write |
|
Unsigned 16 bit (UI2) |
Read/Write |
Read |
Read |
Read |
|
Signed 16 bit (I2) |
Read/Write |
Read |
Read |
Read |
|
Unsigned 32 bit (UI4) |
Read/Write |
Read |
Read |
Read |
|
Signed 32 bit (I4) |
Read/Write |
Read |
Read |
Read |
|
Float (R4) |
Read/Write |
N/A |
Read |
N/A |
|
Double (R8) |
Read/Write |
N/A |
Read |
N/A |
Data Type Conversion
The OPC server allows conversion between the following data types:
|
From/To |
BOOL |
I1 |
UI1 |
I2 |
UI2 |
I4 |
UI4 |
R4 |
R8 |
|---|---|---|---|---|---|---|---|---|---|
|
BOOL |
OK |
! |
! |
! |
! |
! |
! |
! |
! |
|
I1 |
OK |
OK |
! |
! |
! |
! |
! |
! |
! |
|
UI1 |
OK |
OK |
OK |
! |
! |
! |
! |
! |
! |
|
I2 |
OK |
OK |
OK |
OK |
! |
! |
! |
! |
! |
|
UI2 |
OK |
OK |
OK |
OK |
OK |
! |
! |
! |
! |
|
I4 |
OK |
OK |
OK |
OK |
OK |
OK |
! |
! |
! |
|
UI4 |
OK |
OK |
OK |
OK |
OK |
OK |
OK |
! |
! |
|
R4 |
OK |
OK |
OK |
OK |
OK |
OK |
OK |
OK |
! |
|
R8 |
OK |
OK |
OK |
OK |
OK |
OK |
OK |
OK |
OK |
|
Legend: OK – conversion is valid ! – indicates possible overflow. In case of overflow, the target value is not changed. (OPC Data Access Custom Interfaces specification 2.05). |
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