Template: Task

This section specifies the template Task.

The specification comprises a SysML Block that represents the template and an associated Parametric Diagram that defines the templates and PLCS PSM objects instantiated by the Task template.

The specification comprises the following sections:

Section Description provides a description of the template;
Section Template Block specifies the SysML Block that represents the template;
Section Template Properties specifies the properties, i.e. the Part, Reference and Value properties of the templates SysML Block;
Section Template Output Ports specifies the Output Ports of the templates SysML Block. These bind to the templates and PLCS PSM objects instantiated by the Task template as described in section Template Parametric Diagram;
Section Template Constraints specifies the constraints on PLCS PSM objects instantiated by the Task template;
Section Template Parametric Diagram specifies the templates and PLCS PSM objects instantiated by the Task template;
Section Instantiated blocks specifies the templates and PLCS PSM objects instantiated by the Task template and bound to private parts of the template;
Section Default instances species the instances that have been instantiated in the template. These are used to set the default value of blocks.
Section Constraint blocks identifies the constraint blocks that have been specified in this template;
Section Example data provides example XML data sets that have been instantiated in accordance with this template.

NOTE An explanation of a template and its specification is provided in the Template overview

Description

The Task template describes how to represent a simple task specification. A task specification is a procedural description of how to do something. A simple task specification has a simple, unstructured definition, and may also identify the context in which it is used. More complex tasks are described in the various task capabilities.

A task specification does not plan, schedule, or record what is done. This template is used to define the essential information for the specification, that is:

The task identifier and version;
Task life cycle status;
The task name and description;
A description of how the task is performed, either as a simple literal description or as a reference to an external document.

EXAMPLE task number 123 version 2 "Change Chain" may be specified for a 'Gears-r-us' type 3 Strumly-Bowman gear fitted to a 'Muddy-Badger' model 42 bicycle, and describes the steps needed to change the sprocket chain.

The template mandates only the minimum of information, and most of the information needed for a simple task is described under the characterization section.

This template is valid only for "in-use" stage of the Task specification life cycle, and does not consider the initial development phase, the obsolescence phase, development lifecycle data nor any controls on the development process or the authorizations that record that process.

The template characterization describes a task specified as applying to a specific type of product (the affected product), that is one which can be identified by a part number, as opposed to against a general product configuration, or a task written against a specific individual, for example, as a repair for specific damage. Where the affected product is fitted to a higher level end product (e.g. the task describes how to maintain a particular type of pump when fitted in a given class of ship), the characterization also describes how to identify the higher level product.

The template characterization allows for the task instructions to be held either as unstructured text or in a separate document.

The SysML Block Definition diagram in Figure 1 shows how a Task is represented in the PLCS PSM.

../../../../../data/PLCS/psm_model/images/SysML_Block_Definition_Diagram__Diagrams__Task.png

Figure 1 - Part model

Related Templates

No templates have been explicitly defined as being related to the Task template.

NOTE The Task template may make reference to other templates as part of the Parametric Diagram. These are not listed here.

Template Block

Figure 2 shows the SysML Block that represents the template. The Block is an abstraction representing a pattern of templates and PLCS PSM objects.

The properties, i.e. the SysML Block Part, Reference and Value properties, of the template's SysML Block are described in the Template Properties section.

The output ports shown on the template's SysML Block are described in the template output ports section.

Figure 2 - Template block definition diagram for Task

Template Properties

The following Part, Reference, and Value properties are defined for this template:

Parts:

ids [1..*] (Template: OASIS:Identification)

The identifiers of the task , e.g. the task number.

The reference data used in Template: OASIS:Identification is restricted as follows:

RDL constraint 1:

There must be one identifier that is the task number.

The reference data for:

OASIS:Task.id -> ExternalOwlClass.class

is restricted to the following class:

http://docs.oasis-open.org/plcs/ns/plcslib/v1.0/data/contexts/OASIS/refdata/plcs-rdl#Task_method_identification_code

versionId [0..1] (Template: OASIS:Identification)

The task version identifier, for example, the sequence number of the version.

NOTE If no versionId is specified a unique, unidentified TaskElement is created.

The reference data used in Template: OASIS:Identification is restricted as follows:

RDL constraint 1:

There must be one identifier that is the task number.

The reference data for:

OASIS:Task.versionId -> ExternalOwlClass.class

is restricted to the following class:

http://docs.oasis-open.org/plcs/ns/plcslib/v1.0/data/contexts/OASIS/refdata/plcs-rdl#Version_identification_code

names [0..*] (Template: OASIS:Name)

The collection of names of the task.

taskContent [0..1] (Block: Ap239Ap233Psm:TaskElement)

The TaskElement that details the decomposition of the task into one or more task steps.

classifications [0..*] (Template: OASIS:Classifier)

The collection of classifications of the task

descriptions [0..*] (Template: OASIS:Descriptor)

The collection of descriptions of the task

Template Output Ports

The following output ports are defined for this template:

taskMethod (Block: Ap239Ap233Psm:TaskMethod)

Enables the Block: Ap239Ap233Psm:TaskMethod instantiated by this template to be referenced when the template is used.

taskMethodVersion (Block: Ap239Ap233Psm:TaskMethodVersion)

Enables the Block: Ap239Ap233Psm:TaskMethodVersion instantiated by this template to be referenced when the template is used.

Template constraints

There are no constraints defined for this template.

Template Parametric diagram

This section describes the template's Parametric Diagram. The diagram details the pattern of templates and PLCS PSM objects that are required to represent the template Task.

The public properties, i.e. those visible in the template's SysML block (See Figure 2) are shown on the left of a Parametric Diagram.

NOTE Restrictions on the reference data to be set on the public properties is defined in the Template Properties section.

The output ports are shown on the right of the Parametric Diagram.

PLCS PSM objects are shaded khaki and template shaded light green in a Parametric Diagram.

Figure 3 - Parametric diagram for Task

Instantiated Blocks

The following blocks are instantiated by this template and bound to private parts of the template as shown in the Parametric Diagram section:

Private Part Property:task [1] (Block: Ap239Ap233Psm:TaskMethod)

Private Part Property:taskVersion [0..1] (Block: Ap239Ap233Psm:TaskMethodVersion)

Private Part Property:combNameAndDesc [1] (Constraint Block: OASIS:Name:CombineNamesAndDescriptors)

Default instances

There are no instances that have been instantiated in this template.

Constraint Blocks

There are no constraint blocks defined in this template.

Example data

No example data sets have been provided for this DEX.