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 188.8.131.52.
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
|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
Subtype of Structure defined in OPC 10000-5.
|Data Access XYArrayItemType|