This structure defines the information for auxiliary axis for ArrayItemType Variables.
There are three typical uses of this structure:
- The step between points is constant and can be predicted using the range information and the number of points. In this case, axisSteps can be set to NULL.
- The step between points is not constant, but remains the same for a long period of time (from acquisition to acquisition for example). In this case, axisSteps contains the value of each step on the axis.
- The step between points is not constant and changes at every update. In this case, a type like XYArrayType shall be used and axisSteps is set to NULL. Its elements are defined in Table 23.
Table 23 – AxisInformation DataType structure
|engineeringUnits||EUInformation||Holds the information about the engineering units for a given axis.|
|eURange||Range||Limits of the range of the axis|
|title||LocalizedText||User readable axis title, useful when the units are %, the Title may be “Particle size distribution”|
|axisScaleType||AxisScaleEnumeration||LINEAR, LOG, LN, defined by AxisSteps|
|axisSteps||Double||Specific value of each axis steps, may be set to “Null” if not used|
Its representation in the AddressSpace is defined in Table 24.
Table 24 – AxisInformation definition
Subtype of Structure defined in OPC 10000-5.
|Data Access AxisInformationType|
When the steps in the axis are constant, axisSteps may be set to “Null” and in this case, the Range limits are used to compute the steps. The number of steps in the axis comes from the parent ArrayItem.ArrayDimensions.