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5.6.8 XVType ToC Previous Next

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 27.

Table 27 – XVType DataType structure

Name Type Description
XVType structure  
         x       Double Position on the X axis of this value
         value       Float The value itself

Its representation in the AddressSpace is defined in Table 28.

Table 28 – XVType definition

Attribute Value
BrowseName XVType
IsAbstract False

Subtype of Structure defined in OPC 10000-5.

References NodeClass BrowseName DataType TypeDefinition Other
Conformance Units          
Data Access XYArrayItemType          

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