OPC Client Write Request Conversions

Extensibility > Using an OPC DA Server > OPC DA Server Reference Information > OPC Client Write Request Conversions

OPC client write request conversions

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

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

Note: For write operations that result in an overflow, OPC E_FAIL will be returned and the target SCADA value will not be changed.

See Also

OPC client read request conversions

OPC DA Server reference information

Published June 2018