5.6.9 XVType

This structure defines a physical value relative to a X axis and it is used as the DataType of the Value of XYArrayItemType. For details see 5.3.4.3.

Many devices can produce values that can perfectly be represented with a float IEEE 32 bits but, they can position them on the X axis with an accuracy that requires double IEEE 64 bits. For example, the peak value in an absorbance spectrum where the amplitude of the peak can be represented by a float IEEE 32 bits, but its frequency position required 10 digits which implies the use of a double IEEE 64 bits.

Its elements are defined in Table 35.

Table 35 – XVType DataType structure
NameTypeDescription
XVTypestructure

x

DoublePosition on the X axis of this value

value

FloatThe value itself

Its representation in the AddressSpace is defined in Table 36.

Table 36 – XVType definition
Attribute Value
BrowseNameXVType
IsAbstractFalse
References NodeClass BrowseName DataType TypeDefinition Other
Subtype of Structure defined in OPC 10000-5.
Conformance Units
Data Access XYArrayItemType