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 AddressSpace is 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, 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.