.NET Based OPC UA Client/Server SDK
3.1.0.500

Defines the Range for a value.
Field  DataType  ValueRank  Description 

Low  Double  Scalar  Lowest value in the range. 
High  Double  Scalar  Highest value in the range. 
Contains information about the EngineeringUnits.
Understanding the units of a measurement value is essential for a uniform system. In an open system in particular where servers from different cultures might be used, it is essential to know what the units of measurement are. Based on such knowledge, values can be converted if necessary before being used. Therefore, although defined as optional, support of the EngineeringUnits Property is strongly advised.
To facilitate interoperability, OPC UA specifies how to apply the widely accepted “Codes for Units of Measurement (Recommendation No. 20)” published by the “United Nations Centre for Trade Facilitation and Electronic Business” (see UN/CEFACT). It uses and is based on the International System of Units (SI Units) but in addition provides a fixed code that can be used for automated evaluation. This recommendation has been accepted by many industries on a global basis.
Field  DataType  ValueRank  Description 

NamespaceUri  String  Scalar  Identifies the organization (company, standards organization) that defines the EUInformation. 
UnitId  Int32  Scalar  Identifier for programmatic evaluation. More... 
DisplayName  LocalizedText  Scalar  The displayName of the engineering unit. More... 
Description  LocalizedText  Scalar  Contains the full name of the engineering unit such as ”hour” or ”meter per second”. 
Identifier for programmatic evaluation.
−1 is used if a unitId is not available.
The displayName of the engineering unit.
This is typically the abbreviation of the engineering unit, for example ”h” for hour or ”m/s” for meter per second.
Identifies on which type of axis the data shall be displayed.
Enum String  Enum Value  Description 

Linear  0  Linear Scale 
Log  1  Log base 10 scale 
Ln  2  Log base e scale 
Defines the information for auxiliary axis for ArrayItemType Variables.
There are three typical uses of this structure:
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.
Field  DataType  ValueRank  Description 

EngineeringUnits  EUInformation  Scalar  Holds the information about the engineering units for a given axis. 
EURange  Range  Scalar  Limits of the range of the axis 
Title  LocalizedText  Scalar  User readable axis title. More... 
AxisScaleType  AxisScaleEnumeration  Scalar  LINEAR, LOG, LN, defined by AxisSteps (see AxisScaleEnumeration). 
AxisSteps  Double  Array  Specific value of each axis step. More... 
User readable axis title.
This is useful when the units are %. The Title may be e.g. “Particle size distribution”
Specific value of each axis step.
May be set to “Null” if not used.
Defines a physical value relative to a X axis and it is used as the DataType of the Value of XYArrayItemType.
Most analysers 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.
Field  DataType  ValueRank  Description 

X  Double  Scalar  Position on the X axis of this value. 
Value  Float  Scalar  The value itself. 