This structure defines the information for auxiliary axis for ArrayItemType Variables.

There are three typical uses of this structure:

  1. 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.
  2. 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.
  3. 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 26.

Table 26– AxisInformation DataType structure

Name

Type

Description

AxisInformation

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 AddressSpaceis defined in Table 27.

Table 27– AxisInformation definition

Attribute

Value

BrowseName

AxisInformation

IsAbstract

False

References

NodeClass

BrowseName

DataType

TypeDefinition

Other

Subtype of Structure defined in OPC 10000-5.

Conformance Units

Data Access AxisInformationType

When the steps in the axis are constant,axisStepsmay be set to “Null” and in this case, the Rangelimits are used to compute the steps. The number of steps in the axis comes from the parent ArrayItem.ArrayDimensions.