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AVEVA™ Plant SCADA

OPC Client Read Request Conversions

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OPC Client Read Request Conversions

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Last UpdatedJul 13, 2023
2 minute read

The following table describes the outcomes that can be expected when converting Plant SCADA data types to OPC data types during client read requests.

OPC Data Types (To)	Plant SCADA Data Types (From)
OPC Data Types (To)	BYTE	INT	UINT, BCD	LONG	ULONG, LONG- BCD	REAL	STRING (256 bytes)	DIGITAL
I1	Overflow if out of range	Overflow if out of range	Overflow if out of range	Overflow if out of range	Overflow if out of range	Overflow if out of range	Overflow if out of range	OK
UI1	OK	Overflow if out of range	Overflow if out of range	Overflow if out of range	Overflow if out of range	Overflow if out of range	Overflow if out of range	OK
I2	OK	OK	Overflow if out of range	Overflow if out of range	Overflow if out of range	Overflow if out of range	Overflow if out of range	OK
UI2	OK	Overflow if out of range	OK	Overflow if out of range	Overflow if out of range	Overflow if out of range	Overflow if out of range	OK
I4	OK	OK	OK	OK	Overflow if out of range	Overflow if out of range	Overflow if out of range	OK
UI4	OK	Overflow if out of range	OK	Overflow if out of range	OK	Overflow if out of range	Overflow if out of range	OK
R4	OK	OK	OK	OK	OK	OK	Overflow if out of range	OK
R8	OK	OK	OK	OK	OK	OK	Overflow if out of range	OK
CY	OK	OK	OK	OK	OK	OK	Overflow if out of range	OK
DATE	OK	OK	OK	OK	OK	OK	Overflow if out of range	OK
BSTR	OK	OK	OK	OK	OK	OK	OK	OK
BOOL	OK	OK	OK	OK	OK	OK	Overflow if out of range	OK

Note: For read operations that result in an overflow, OPC E_FAIL will be returned and read quality will be set to BAD.

See Also

OPC Client Write Request Conversions

OPC DA Server Reference Information

Related Links

Client Request Data Type Conversions