The CalibrationValueType is a subtype of the DataItemType. It represents the specific quantity and value (with engineering unit) that a calibration target provides for calibration of equipment. The VariableType is formally defined in Table 55.
Table 55 – CalibrationValueType Definition
|ValueRank||−2 (−2 = Any)|
|Description||Represents the specific quantity and value (with engineering unit) that a calibration target provides for calibration of equipment.|
Subtype of the 0:DataItemType defined in OPC 10000-8, i.e. inheriting the InstanceDeclarations of that Node
The CalibrationValueType inherits the Properties of the DataItemType. That does include the optional 0:ValuePrecision, defining the precision of the calibration value.
The mandatory 0:EngineeringUnits defines the engineering unit of the calibration values.
Remark: The quantity of the calibration value is of importance. This specification waits for this to be solved in the base OPC UA specification (OPC 10000-8), and will use this afterwards.
The VariableType can be used with an (multi-dimensional) array or scalar values. When a calibration target provides several independent values, e.g., lengths, that can be used for calibration, each one should get its own instance of CalibrationValueType. If the calibration target provides for example a scale for length, the CapacityRangeType should be used. The array of the CalibrationValueType shall only be used, when it represents one overall value consisting of a number of distinct values for example the spatial frequency of line pattern blocks on a resolution test chart for calibration of optical instruments.