Business overview

This section provides a business level overview of this capability.

Condition can be used to express if-statements consisting of operators and operands (parameters).

Information model overview

This section provides an overview of the information model that supports this capability.

Comparison expression

Representing a Text Based Condition

Representing a Condition as a text based description is the simplest form of condition representation.

A text based condition could be expressed as an IF-statement as follows:

If text_based_condition Then statement sequence.

The text_based_condition could be any text, describing of the actual condition.

A text based condition is represented by the condition module as follows:

• Condition - Represents the If statement. The Condition should be classified as [TextBasedCondition]
  Error RDL1: The class TextBasedCondition does not exist in RDL at URI urn:plcs:rdl:std. Check the dexlib/data/refdata/rdl_index.xml
  ;
• Condition_assignment - An association to the entity which is dependent upon the result of the If statement (represents the Then statement sequence);
• Condition  description attribute - A text based description of the condition.

Error I1; The image filename: ../Repr a text based condition.png contains whitespace

Figure 1 —  Example of a text based condition. The non-shaded entities are outside the scope of the 'Representing a condition' capability.

Representing a Comparison Expression

Representing a comparison expression as a condition includes the usage of condition parameters.

The representation of a comparison based condition could be expressed as an IF-statement as follows:

If comparison_expression Then statement sequence.

The comparison_expression part of the statement is often defined as:

operand1  comparison_operator  operand2.

The comparison operators are: 'Equals', 'Greater than', 'Greater than or equal to', 'Less than', 'Less than or equal to' and 'Not equal'.

This If-statement is represented by the condition module as follows:

Condition - Represents the If statement. The Condition should be classified as [Equals]
Error RDL1: The class Equals does not exist in RDL at URI urn:plcs:rdl:std. Check the dexlib/data/refdata/rdl_index.xml
, [GreaterThan]
Error RDL1: The class GreaterThan does not exist in RDL at URI urn:plcs:rdl:std. Check the dexlib/data/refdata/rdl_index.xml
, [GreaterThanOrEqualTo]
Error RDL1: The class GreaterThanOrEqualTo does not exist in RDL at URI urn:plcs:rdl:std. Check the dexlib/data/refdata/rdl_index.xml
, [LessThan]
Error RDL1: The class LessThan does not exist in RDL at URI urn:plcs:rdl:std. Check the dexlib/data/refdata/rdl_index.xml
, [LessThanOrEqualTo]
Error RDL1: The class LessThanOrEqualTo does not exist in RDL at URI urn:plcs:rdl:std. Check the dexlib/data/refdata/rdl_index.xml
or [NotEqual]
Error RDL1: The class NotEqual does not exist in RDL at URI urn:plcs:rdl:std. Check the dexlib/data/refdata/rdl_index.xml
;

Condition_parameter - Represents the operands. The Condition_parameter should be classified as [Operand1]
Error RDL1: The class Operand1 does not exist in RDL at URI urn:plcs:rdl:std. Check the dexlib/data/refdata/rdl_index.xml
or [Operand2]
Error RDL1: The class Operand2 does not exist in RDL at URI urn:plcs:rdl:std. Check the dexlib/data/refdata/rdl_index.xml
.

Error I1; The image filename: ../Repr a comparison condition.png contains whitespace

Figure 2 —  Example of a comparison based condition. The non-shaded entities are outside the scope of the 'Representing a condition' capability.

The example in Figure 2 represents the following condition :

Task#13 will be performed on Part#29 IF the property flight hours of the the Part in which Part#29 is mounted is greater than the property flight hours interval of Part#29.

Representing a Logical expression

Representing a logical expression as a condition includes the usage of condition relationship.

The representation of a logical expression as an IF-statement is often expressed as follows

If logical_expression Then statement sequence.

The logical_expression part of the statement is often defined as:

comparison_expression_1 logical_operator comparison_expression_1.

The logical operators are: 'AND', 'OR', 'XOR' and 'NOT'.

A logical expression is represented by the condition module as follows:

• Condition - Represents the If statement. The Condition should be classified as [LogicalExpression]
  Error RDL1: The class LogicalExpression does not exist in RDL at URI urn:plcs:rdl:std. Check the dexlib/data/refdata/rdl_index.xml
  ;
• Condition_assignment - An association to the entity which is dependent upon the result of the If statement (represents the Then statement sequence);
• Condition_relationship as the Condition_parameter - Represents the logical expression. The Condition_relationship should be classified as "AND" (urn:plcs:rdl:std:AND), "OR" (urn:plcs:rdl:std:OR), [Xor]
  Error RDL1: The class Xor does not exist in RDL at URI urn:plcs:rdl:std. Check the dexlib/data/refdata/rdl_index.xml
  or [Not]
  Error RDL1: The class Not does not exist in RDL at URI urn:plcs:rdl:std. Check the dexlib/data/refdata/rdl_index.xml
  ;
• Condition - Represents the comparison expressions. For details on how to represent comparison expressions, see above.

Error I1; The image filename: ../Repr a logical expression condition.png contains whitespace

Figure 3 —  Example of a logical expression condition. The conditions #36 and #37 could be either text-based, comparison or logical expression conditions.

Model Characterization

This section specifies how the information model can be further characterized by the assignment of additional information such as dates, approvals and people or organizations.

The following characterizations may apply.

Characterization: Classification of a condition (Optional)

A condition shall always be classified in accordance with the classes described above.

NOTE    Multiple classifications of a condition is likely to occur.

Characterization: Classification of a condition relationship (Optional)

A condition relationship representing a logical expression should always be classified in accordance with the classes described above.

NOTE    Multiple classifications of a condition relationship is likely to occur.

Characterization: Classification of a condition parameter (Optional)

A condition parameter shall always be classified in accordance with the classes described above.

NOTE    Multiple classifications of a condition parameter is likely to occur.

Characterization: Classification of a condition assignment (Optional)

Classification of a condition assignment could be used to represent the role of the assignment.

The classification is context dependent. An example of a classification of a condition assignment may be [TaskTrigger]
Error RDL1: The class TaskTrigger does not exist in RDL at URI urn:plcs:rdl:std. Check the dexlib/data/refdata/rdl_index.xml
in a maintenance plan.

Out of scope

Enumeration of entity types that a condition could be assigned to is outside the scope of this capability.

Enumeration of entity types that could be referenced as condition parameters is outside the scope of this capability.

Capability templates

The following sections define a set of templates for the capability, where a template is a specification of a set of entities that need to be instantiated to represent a given set of information.

This section specifies the template assigning_condition.

NOTE  An explanation of a template and the associated instantiation path is provided in the Template overview section.

Figure 1 —  EXPRESS-G representation for the template 'assigning_condition'

Figure 2 —  Graphical representations for the template 'assigning_condition'

Figure 3 —  Instance diagram instantiated by the template example

Figure 4 —  Invocation of template - graphical presentation

This section specifies the template assigning_condition_parameter.

NOTE  An explanation of a template and the associated instantiation path is provided in the Template overview section.

Figure 1 —  An EXPRESS-G representation of the Information model for assigning_condition_parameter

Figure 2 —  The graphical representation of the assigning_condition_parameter template

Figure 3 —  Entities instantiated by assigning_condition_parameter template

          #1 = CONDITION('/IGNORE','/IGNORE');
          #2 = INDEPENDENT_PROPERTY('/IGNORE','/IGNORE','/IGNORE');
          #3 = CONDITION_PARAMETER('/IGNORE','/IGNORE',#1,#2);
          #5 = CLASSIFICATION_ASSIGNMENT(#6,(#3),'/IGNORE');
          #6 = EXTERNAL_CLASS('/NULL','Trigger','/IGNORE',#7);
          #7 = EXTERNAL_CLASS_LIBRARY('urn:plcs:rdl:sample','/IGNORE');
        

Figure 4 —  Instantiation of assigning_condition_parameter template

This section specifies the template assigning_condition_text_based.

NOTE  An explanation of a template and the associated instantiation path is provided in the Template overview section.

Figure 1 —  EXPRESS-G representation for the template 'assigning_condition_text_based'

Figure 2 —  Graphical representations for the template 'assigning_condition'

Figure 3 —  Instance diagram instantiated by the template example

Figure 4 —  Invocation of template - graphical presentation

This section specifies the template representing_condition_relationship.

NOTE  An explanation of a template and the associated instantiation path is provided in the Template overview section.

Figure 1 —  An EXPRESS-G representation of the Information model for representing_condition_relationship

Figure 2 —  The graphical representation of the representing_condition_relationship template

Figure 3 —  Entities instantiated by representing_condition_relationship template

Figure 4 —  Instantiation of representing_condition_relationship template

Dependent capabilities

This capability "Representing a Condition" is dependent on the following capabilities:

• C010: assigning_reference_data

Model reference data

The following classes of reference data are required for this capability:

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