Three types of monitoring criteria supported by this part of ISO 15926 are shown in Table 2.

Table 2 — Types of monitoring criteria

A monitoring criterion is a subclass of time_variation_of_property.

A monitoring_activity monitors a time_variation_of_property. Whenever a monitoring_activity detects a part of the time_variation_of_property which complies with one of the specified monitoring criterion, it issues a message.

:OilTemperature100DegreeCrossing
   a                        iso15926-x:level_crossing_criterion ;
   iso15926-x:set_level     [ iso15926-4:celsius [ basics:decimal "100" ] ] ;
   iso15926-x:set_tolerance [ iso15926-4:celsius [ basics:decimal "10" ] ] ;
   rdfs:subClassOf          [ owl:onProperty rdfs:subPropertyOf ;
                              owl:hasValue   myOnt:oilTemperature ] .

An object is a class_of_time_variation_of_property if and only if:

• it is the powerset of time_variation_of_property.

-->
<owl:Class rdf:about="&iso15926-x;class_of_time_variation_of_property">
 <owl:sameAs>
  <owl:Restriction>
   <owl:onProperty rdf:resource="&rdfs;subClassOf"/>
   <owl:hasValue rdf:resource="&iso15926-x;time_variation_of_property"/>
  </owl:Restriction>
 </owl:sameAs>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/monitoring_criterion.htm#class_of_time_variation_of_property"/>
</owl:Class>
<!--

An object is a class_of_class_of_time_variation_of_property if and only if:

• it is the powerset of class_of_time_variation_of_property.

-->
<owl:Class rdf:about="&iso15926-x;class_of_class_of_time_variation_of_property">
 <owl:sameAs>
  <owl:Restriction>
   <owl:onProperty rdf:resource="&rdfs;subClassOf"/>
   <owl:hasValue rdf:resource="&iso15926-x;class_of_time_variation_of_property"/>
  </owl:Restriction>
 </owl:sameAs>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/monitoring_criterion.htm#class_of_class_of_time_variation_of_property"/>
</owl:Class>
<!--

An object is a level_crossing_criterion if and only if:

• it is a class_of_time_variation_of_property;

• it consists of each time_variation_of_property such that either:

  • when going up: x₁ < l - ε/2 and x₂ > l + ε/2 ; or
  • when going down: x₁ > l + ε/2 and x₂ < l - ε/2 ,

  where:

  • x₁ is the value of the time_variation_of_property at the beginning of its domain;
  • x₂ is the value of the time_variation_of_property at the end of its domain;
  • l is the set level which is specified by a set_level property;
  • ε is the set tolerance which is specified by a set_tolerance property.

EXAMPLE Figure 5 shows level crossing criteria at 100 degrees Celsius and 120 degrees Celsius with a tolerance of 10 degrees. The parts of the time_variation_of_property highlighted in green are members of the criteria, but the part highlighted in red is not.

Figure 5: Level crossing examples

-->
<owl:Class rdf:about="&iso15926-x;level_crossing_criterion">
 <rdfs:subClassOf rdf:resource="&iso15926-x;class_of_time_variation_of_property"/>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/monitoring_criterion.htm#level_crossing_criterion"/>
</owl:Class>
<!--

An object is a change_criterion if and only if:

• it is a class_of_time_variation_of_property;

• it consists of each time_variation_of_property such that either:

  • when going up: x₂ > x₁ + ε , or
  • when going down: x₂ < x₁ - ε ,

  where:

  • x₁ is the value of the time_variation_of_property at the beginning of its domain;
  • x₂ is the value of the time_variation_of_property at the end of its domain;
  • ε is the set tolerance which is specified by a set_tolerance property.

EXAMPLE Figure 6 shows a change criterion with a tolerance of 20 degrees. The parts of the time_variation_of_property highlighted in yellow are members of the criterion. Other parts are also members of the criterion, but a monitoring_activity does not report changes which overlap.

Figure 6: Change examples

-->
<owl:Class rdf:about="&iso15926-x;change_criterion">
 <rdfs:subClassOf rdf:resource="&iso15926-x;class_of_time_variation_of_property"/>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/monitoring_criterion.htm#change_criterion"/>
</owl:Class>
<!--

An object is a noise_criterion if and only if:

• it is a class_of_time_variation_of_property;

• it consists of each time_variation_of_property that contains one or more parts of duration > δ for which there does not exists a level l such that:

  • l - ε < X(t) < l + ε , for all t within the part

  where:

  • X(t) is a part time_variation_of_property;
  • ε is the set tolerance which is specified by a set_tolerance property.
  • δ is the set minimum interval which is specified by a set_minimum_interval property.

EXAMPLE Figure 7 shows a noise criterion that is defined by a variation of more than 10 degrees in 5 minutes. The parts of the time_variation_of_property highlighted in green are members of the criterion.

Figure 7: Noise example

-->
<owl:Class rdf:about="&iso15926-x;noise_criterion">
 <rdfs:subClassOf rdf:resource="&iso15926-x;class_of_time_variation_of_property"/>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/monitoring_criterion.htm#noise_criterion"/>
</owl:Class>
<!--

An object is a going_up if and only if:

• it is a time_variation_of_property such that:

  • x₂ > x₁ ,

  where:

  • x₁ is the value of the time_variation_of_property at the beginning of its domain;
  • x₂ is the value of the time_variation_of_property at the end of its domain.

-->
<owl:Class rdf:about="&iso15926-x;going_up">
 <rdfs:subClassOf rdf:resource="&iso15926-x;class_of_time_variation_of_property"/>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/monitoring_criterion.htm#going_up"/>
</owl:Class>
<!--

An object is a going_down if and only if:

• it is a time_variation_of_property such that:

  • x₂ < x₁ ,

  where:

  • x₁ is the value of the time_variation_of_property at the beginning of its domain;
  • x₂ is the value of the time_variation_of_property at the end of its domain.

-->
<owl:Class rdf:about="&iso15926-x;going_down">
 <rdfs:subClassOf rdf:resource="&iso15926-x;class_of_time_variation_of_property"/>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/monitoring_criterion.htm#going_down"/>
</owl:Class>
<!--

An object is a set_level relationship if and only if:

• it is a basics:function between level_crossing_criterion and basics:algebraic_field;
• it specifies that a level_crossing_criterion has the member of the basics:algebraic_field as its set level.

-->
<owl:FunctionalProperty rdf:about="&iso15926-x;set_level">
 <rdfs:domain rdf:resource="&iso15926-x;level_crossing_criterion"/>
 <rdfs:range rdf:resource="&basics;algebraic_field"/>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/monitoring_criterion.htm#set_level"/>
</owl:FunctionalProperty>
<!--

An object is a set_tolerance relationship if and only if:

• it is a basics:function between the union of level_crossing_criterion, change_criterion and noise_criterion, and basics:algebraic_field;
• it specifies that a member of the domain has a member of the basics:algebraic_field as its set tolerance.

-->
<owl:FunctionalProperty rdf:about="&iso15926-x;set_tolerance">
 <rdfs:domain>
  <owl:Class>
   <owl:unionOf rdf:parseType="Collection">
    <owl:Class rdf:about="&iso15926-x;level_crossing_criterion"/>
    <owl:Class rdf:about="&iso15926-x;change_criterion"/>
    <owl:Class rdf:about="&iso15926-x;noise_criterion"/>
   </owl:unionOf>
  </owl:Class>
 </rdfs:domain>
 <rdfs:range rdf:resource="&basics;algebraic_field"/>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/monitoring_criterion.htm#set_tolerance"/>
</owl:FunctionalProperty>
<!--

An object is a set_minimum_interval relationship if and only if:

• it is a basics:function between noise_criterion and geometry_basics:time_duration;
• it specifies that a noise_criterion has the geometry_basics:time_duration as its minimum interval.

-->
<owl:FunctionalProperty rdf:about="&iso15926-x;set_minimum_interval">
 <rdfs:domain rdf:resource="&iso15926-x;noise_criterion"/>
 <rdfs:range rdf:resource="&geometry_basics;time_duration"/>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/monitoring_criterion.htm#set_minimum_interval"/>
</owl:FunctionalProperty>
<!--

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