The lifetime model provides information about the lifetime, related limits and semantic of the lifetime of things like tools, material or machines.

Table 106 illustrates the model with two examples, showing the information that can be provided with the model defined in this chapter. The Value of the LifetimeVariable provides the current value. The EngineeringUnits Property and the relation of the Indication to a classification ObjectType provide the semantic. The StartValue and LimitValue Properties indicate the range of the Value.

Table 106 – Lifetime examples

Node

CertificateValidity

PartsProduced

LifetimeVariable

200

553

               EngineeringUnits (M)

day

number of parts

               StartValue (M)

365

0

               WarningValues (O)

10

950

               LimitValue (M)

0

1000

               Indication (O)

TimeIndicationType

NumberOfPartsIndicationType

For the CertificateValidity example, the instance of the LifetimeVariableType defines the remaining validity of a certificate with a unit of days and a classification of TimeIndication. The Value specifies 200 days – the remaining validity of a certificate. The initial value is 365 days with a warning level of 10 days. The certificate is invalid when the Value is zero.

For the PartsProduced example, the instance of the LifetimeVariableType defines the produced parts in the lifetime with a classification of NumberOfPartsIndication. The Value specifies 553 parts. The starting value is 0 parts and it is possible to produce up to 1000 parts with a warning indication if the number reaches 950.

The LifetimeVariableType defines Variables representing the remaining lifetime. It provides generically the remaining lifetime and can be used on anything; for example, on machines, actuators or sensors, but also on immaterial things like software. It is formally defined in Table 107.

Table 107 – LifetimeVariableType definition

Attribute

Value

BrowseName

LifetimeVariableType

IsAbstract

False

ValueRank

−1 (−1 = Scalar)

DataType

Number

Description

Remaining lifetime

References

Node Class

BrowseName

DataType

TypeDefinition

Other

Subtype of the 0:AnalogUnitType

0:HasProperty

Variable

StartValue

0:Number

0:PropertyType

M

0:HasProperty

Variable

LimitValue

0:Number

0:PropertyType

M

0:HasProperty

Variable

Indication

0:NodeId

0:PropertyType

O

0:HasProperty

Variable

WarningValues

0:Number{ScalarOrOneDimension}

0:PropertyType

O

Conformance Units

DI LT Lifetime Base

The mandatory StartValue indicates the initial value, when there is still the full lifetime left. The engineering unit is the same as for the Value of the Variable, provided by the LifetimeVariableType's mandatory 0:EngineeringUnits, derived from the 0:AnalogUnitType. The DataType shall be the same as for the Value of the Variable.

The mandatory LimitValue indicates when the end of lifetime has been reached. The engineering unit is the same as for the Value of the Variable, provided by the LifetimeVariableType's mandatory 0:EngineeringUnits, derived from the 0:AnalogUnitType. The DataType shall be the same as for the Value of the Variable.

If the StartValue is larger than the LimitValue, the Value of the Variable is expected to move over the time downwards to the LimitValue, otherwise upwards to the LimitValue.

The optional Indication gives an indication of what is actually measured / represented by the Value of the Variable and the StartValue and LimitValue. The mandatory 0:EngineeringUnits, derived from the 0:AnalogUnitType already does this, to a certain degree. But for example, a length unit does not indicate what length is provided, like the cutting distance, the feed distance or the abraded length of a tool. The Indication contains a NodeId of the BaseLifetimeIndicationType or a subtype of it, providing a more detailed indication.

Note: It is expected that companion specifications or vendors may define additional subtypes of BaseLifetimeIndicationType.

The optional WarningValues defines one or more limits when the end of lifetime is reached soon and may be used to inform the user. Servers may also generate Events when such a limit is reached. If provided, the WarningValues shall be between the StartValue and the LimitValue. If it contains more than one entry, the first array entry defines a warning level with lowest severity. The following entries increase the severity so that the highest entry defines the most serious level.

The engineering unit is the same as for the Value of the Variable, provided by the LifetimeVariableType's mandatory 0:EngineeringUnits, derived from the 0:AnalogUnitType. The DataType shall be the same as for the Value of the Variable.

This VariableType can be used in various cases. Examples include

  • The Variable may just indicate the remaining lifetime as a percentage value. In that case, the 0:EngineeringUnits is percentage, the StartValue is 100 and the LimitValue is 0 (or vice versa if counted upwards).
  • The Variable may represent the number of parts produced. In this case, the 0:EngineeringUnits is One, the StartValue is 0 and the LimitValue the maximum producible parts (e.g. 100 000); or vice versa if the number of remaining parts that still can be produced is provided.
  • The Variable may represent the remaining time, for example until a software license becomes invalid. The 0:EngineeringUnits could be “Day”, “Month”, “Year”, etc., the StartValue 0 and the LimitValue the overall duration, or vice versa if the remaining time is provided.

The child Nodes of the LifetimeVariableType have additional Attribute values defined in Table 108.

Table 108 – LifetimeVariableType Attribute values for child Nodes

BrowsePath

Description Attribute

StartValue

StartValue indicates the initial value, when there is still the full lifetime left.

LimitValue

LimitValue indicates when the end of lifetime has been reached.

Indication

Indication gives an indication of what is actually measured / represented by the Value of the Variable and the StartValue and LimitValue.

WarningValues

WarningValues indicates one or more levels when the end of lifetime is reached soon and may be used to inform the user when reached.

The BaseLifetimeIndicationType defines the base indication of a Variable of LifetimeVariableType, without defining any specific semantic. Servers should use a more specific subtype, if possible. It is formally defined in Table 109.

Table 109 – BaseLifetimeIndicationType definition

Attribute

Value

BrowseName

BaseLifetimeIndicationType

IsAbstract

True

Description

Base indication type not further defining a semantic

References

Node Class

BrowseName

DataType

TypeDefinition

Other

Subtype of the 0:BaseObjectType

Conformance Units

DI LT Lifetime Base

The TimeIndicationType indicates the time the entity has been in use or can still be used. It is formally defined in Table 110.

Table 110 – TimeIndicationType definition

Attribute

Value

BrowseName

TimeIndicationType

IsAbstract

True

Description

Indicates the time the entity has been in use or can still be used

References

Node Class

BrowseName

DataType

TypeDefinition

Other

Subtype of the BaseLifetimeIndicationType

Conformance Units

DI LT Time Indication

The NumberOfPartsIndicationType indicates total number of parts that have been produced or can still be produced. It is formally defined in Table 111.

Table 111 – NumberOfPartsIndicationType definition

Attribute

Value

BrowseName

NumberOfPartsIndicationType

IsAbstract

True

Description

Indicates the total number of parts that have been produced or can still be produced.

References

Node Class

BrowseName

DataType

TypeDefinition

Other

Subtype of the BaseLifetimeIndicationType

Conformance Units

DI LT Nb Of Parts Indication

The NumberOfUsagesIndicationType indicates counting the process steps the entity has been used or can still be used for (for example usages of a punching tool). It is formally defined in Table 112.

Table 112 – NumberOfUsagesIndicationType definition

Attribute

Value

BrowseName

NumberOfUsagesIndicationType

IsAbstract

True

Description

Indicates counting the process steps the entity has been used or can still be used for (for example usages of a punching tool).

References

Node Class

BrowseName

DataType

TypeDefinition

Other

Subtype of the BaseLifetimeIndicationType

Conformance Units

DI LT Nb Of Usages Indication

The LengthIndicationType indicates the abraded length, for example of a drill. It is formally defined in Table 113.

Table 113 – LengthIndicationType definition

Attribute

Value

BrowseName

LengthIndicationType

IsAbstract

True

Description

Indicates the abraded length, for example of a drill.

References

Node Class

BrowseName

DataType

TypeDefinition

Other

Subtype of the BaseLifetimeIndicationType

Conformance Units

DI LT Length Indication

The DiameterIndicationType indicates the abraded diameter, for example of a drill. It is formally defined in Table 114.

Table 114 – DiameterIndicationType definition

Attribute

Value

BrowseName

DiameterIndicationType

IsAbstract

True

Description

Indicates the abraded diameter, for example of a drill.

References

Node Class

BrowseName

DataType

TypeDefinition

Other

Subtype of the BaseLifetimeIndicationType

Conformance Units

DI LT Diameter Indication

The SubstanceVolumeIndicationType indicates the volume of a substance, for example of a liquid. It is formally defined in Table 115.

Table 115 – SubstanceVolumeIndicationType definition

Attribute

Value

BrowseName

SubstanceVolumeIndicationType

IsAbstract

True

Description

Indicates the volume of a substance, for example of a liquid.

References

Node Class

BrowseName

DataType

TypeDefinition

Other

Subtype of the BaseLifetimeIndicationType

Conformance Units

DI LT Substance Volume Indication