representing_task_element

Template:— representing_task_element_constraint (rep_task_elem_const)
Capability:representing_task

Date: 2011/05/20 08:57:07
Revision: 1.4

Cover Contents Description Model diags.Input params.Ref. params.Instantiation path Instance diags.Characterizations Issues in situ

This section specifies the template representing_task_element_constraint.

NOTE The template has been defined in the context of the capability representing_task which provides an overall description of the relevant parts of the ISO 10303-239 information model and a description of related templates.

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

Description

This template describes how to represent a constraint between two task elements within a certain context, i.e. a time lag between element steps.

Model diagrams

The EXPRESS-G diagram in Figure 1 shows the templates and EXPRESS entities that are required to represent the template "representing_task_element_constraint". The text highlighted in blue shows the template parameters.

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

The graphic for the template to be used in other EXPRESS-G diagrams is shown in Figure 2 below.

Figure 2 — The graphical representation of the representing_task_element_constraint template

Input parameters

The following input parameters are defined for this template:

relating_method (Type= 'ENTITY (Task_element)' )

The Task_element which relates to another Task_element.

related_method (Type= 'ENTITY (Task_element)' )

The Task_element that is being related.

applies_in (Type= 'SELECT (constraint_context)' )

The Task_element or Task_method_version that defines the context within which this constraint applies.

constraint_category (Type='CLASS')

Subclass of "Element constraint" (urn:plcs:rdl:std:Element constraint)

The following classes and their sub-classes can be used:

classifications: "Element_constraint" (urn:plcs:rdl:std:Element_constraint)

constraint_cat_ecl_id (Default=urn:plcs:rdl:std,Type='URN')

The identifier of the External_class_library storing the definition of the class referenced by the parameter @constraint_category.

Reference parameters

The following reference parameters are defined for this template:

elem_const(Type='ENTITY (Element_constraint)')

Allow the Element_constraint entity instantiated in this path to be referenced when this template is used.

Note: The Element_constraint entity can be referenced in a template path by:

%^target = $representing_task_element_constraint.elem_const%

where target is the parameter to which the Element_constraint is bound.

Uniqueness constraints

The following parameter combinations specify a uniqueness constraint:

Unique constraint: Element constraint

Each instance of the entity (Element_constraint) within the data set shall be uniquely identified by a combination of the following parameters on this template (representing_task_element_constraint) namely: relating_method, related_method, applies_in, constraint_category, constraint_cat_ecl_id.
The instance is referenced by the following template parameter: elem_const.

Instantiation path

The instantiation path shown below specifies the entities that are to be instantiated by the template.

A description of templates and the syntax for the instantiation path is provided in the Templates Help/Information section.

Element_constraint
%^elem_const = Element_constraint%
Element_constraint.name = '/IGNORE'
Element_constraint.description = '/IGNORE'
Element_constraint.relating_method -> @relating_method
Element_constraint.related_method -> @related_method
Element_constraint.applies_in -> @applies_in

-- provide the role of the realization by classifying the Task_method_version_relationship
/assigning_reference_data(
    items=^elem_const,
    class_name=@constraint_category,
    ecl_id=@constraint_cat_ecl_id)/

The following entities are instantiated with attributes as specified:

Entity in path	Value	Inherited from
Element_constraint.name	'/IGNORE'	Activity_method_relationship.name
Element_constraint.description	'/IGNORE'	Activity_method_relationship.description

Instance diagrams

The instance diagram in Figure 3 shows an example of the EXPRESS entities and templates that are instantiated by the template:

/representing_task_element_constraint(relating_method='#3', related_method='#2', applies_in='#1', constraint_category='Start', constraint_cat_ecl_id='urn:plcs:rdl:sample')/

(an illustration of the consolidated representing_task_element_constraint template is shown in Figure 4 below.)

Figure 3 — Entities instantiated by representing_task_element_constraint template

The instance model in STEP ASCII exchange file format (ISO 10303 Part 21 syntax) is:


          #1 = TASK_ELEMENT_SEQUENCE('/IGNORE','/IGNORE','/IGNORE','/IGNORE',$,(#2,#3));
          #2 = TASK_STEP('/IGNORE','/IGNORE','/IGNORE','/IGNORE',$);
          #3 = TASK_STEP('/IGNORE','/IGNORE','/IGNORE','/IGNORE',$);
          #4 = ELEMENT_CONSTRAINT($,$,#3,#2,#1);
          #6 = CLASSIFICATION_ASSIGNMENT(#7,(#4),'/IGNORE');
          #7 = EXTERNAL_CLASS('/NULL','Start','/IGNORE',#8);
          #8 = EXTERNAL_CLASS_LIBRARY('urn:plcs:rdl:sample','/IGNORE');

The instance diagram in Figure 4 shows the graphic symbol for the template that is to be used in other instance diagrams. The example template is:

/representing_task_element_constraint(relating_method='#3', related_method='#2', applies_in='#1', constraint_category='Start', constraint_cat_ecl_id='urn:plcs:rdl:sample')/

Figure 4 — Instantiation of representing_task_element_constraint template

Characterizations

No common characterizations of the template representing_task_element_constraint have been identified. However, the ISO 10303-239 EXPRESS model may enable other assignments to the entities instantiated by the template.