Accessories

Change History

Id Subject Date
Latest Commit KBLFRM-1095: Positioning of accessories on wire instances. 2021-06-09
KBLFRM-1095  Added examples for the interpretation of the ReferenceElement association in case of multiple ReferenceElements 2021-06-09
Initial creation in the ECAD-WIKI 2019-03-11

Part Master Definition

Accessories
Accessories

Part A being an accessory for Part B means, that if Part B is used somewhere in a harness, then Part A might (or must) be used as well. These can be for example backshells, connector housing locks, clips, cable ties. In the VEC, any part classification can be an accessory to another part. A relation between PartVersion and its accessories can be established with a PartRelation in a GeneralTechnicalPartSpecification

Unclassified Parts

The natural language term “accessory” sums up a vast amount of different part types that are used in a harness, but which are not further specified. Meaning that they are relevant for the bill of material (and some other general properties like weight), but their usage is not defined in detail. If a part has to be used in the VEC, that has no individual specification (like e.g. a ConnectorHousingSpecification) it is marked with the PartVersion.primaryPartType=“Other” and a PartOrUsageRelatedSpecification that can be used to define which type of “accessory” it is (via the attribute PartOrUsageRelatedSpecification.specialPartType). Common part attributes can be defined with a GeneralTechnicalPartSpecification.

Example

The following table shows examples for the usage of a PartRelation and the corresponding semantic meanings.

# Example Meaning In numbers
1
1
2
3
4
5
6
7
8
<PartRelation id="id_1">
   <RelationType>Mandatory</RelationType>
   <AccessoryPart>A A A</AccessoryPart>
</PartRelation>
<PartRelation id="id_2">
   <RelationType>Optional</RelationType>
   <AccessoryPart>A A A</AccessoryPart>
</PartRelation>
The part A has to be used exactly 3 times or exactly 6 times. 3 x A ; 6 x A
2
1
2
3
4
<PartRelation id="id_3">
   <RelationType>Optional</RelationType>
   <AccessoryPart>B B</AccessoryPart>
</PartRelation>
The part B has to be used exactly 0 times or exactly 2 times. 0 x B ; 2 x B
3
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
<PartRelation id="id_4">
   <RelationType>Mandatory</RelationType>
   <AccessoryPart>C</AccessoryPart>
</PartRelation>
<PartRelation id="id_5">
   <RelationType>Mandatory</RelationType>
   <AccessoryPart>C</AccessoryPart>
</PartRelation>
<PartRelation id="id_6">
   <RelationType>Mandatory</RelationType>
   <AccessoryPart>C</AccessoryPart>
</PartRelation>
The part C has to be used exactly 3 times. 3 x C
4
1
2
3
4
<PartRelation id="id_4">
   <RelationType>Mandatory</RelationType>
   <AccessoryPart>C C C</AccessoryPart>
</PartRelation>
The part C has to be used exactly 3 times. This is semantically equivalent with example #3. 3 x C
5
1
2
3
4
<PartRelation id="id_7">
   <RelationType>Optional</RelationType>
   <AccessoryPart>D E F</AccessoryPart>
</PartRelation>
The parts D & E & F have to be used exactly 1 times or 0 times. 0..1 x (D,E,F)
6
1
2
3
4
5
6
7
8
<PartRelation id="id_8">
   <RelationType>Optional</RelationType>
   <AccessoryPart>G G G</AccessoryPart>
</PartRelation>
<PartRelation id="id_9">
   <RelationType>Optional</RelationType>
   <AccessoryPart>G G</AccessoryPart>
</PartRelation>
The part G have to be used exactly 0 times or 2, 3, 5 times. (0,2,3,5) x G
7
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
<PartRelation id="id_10">
   <RelationType>Mandatory</RelationType>
   <AccessoryPart>K K K</AccessoryPart>
</PartRelation>
<PartRelation id="id_11">
   <RelationType>Optional</RelationType>
   <AccessoryPart>K</AccessoryPart>
</PartRelation>
<PartRelation id="id_12">
   <RelationType>Optional</RelationType>
   <AccessoryPart>K</AccessoryPart>
</PartRelation>
<PartRelation id="id_13">
   <RelationType>Optional</RelationType>
   <AccessoryPart>K</AccessoryPart>
</PartRelation>
The part K have to be used between 3 and 6 times. 3..6 x K

Instantiation

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This page or section resolves KBLFRM-1095

As described in the previous section, definitions can be made the part master data which accessories are required in which combination for a component. In the implementation in the wiring harness, however, there are also degrees of freedom as to which accessories are actually used. Therefore, the master data can only define valid possibilities; which variant is used must be defined at the concrete occurrence.

In the VEC the accessory occurrenceparent occurrence relationship is represented by the ReferenceElement association, where the accessory occurrence references the OccurrenceOrUsage it depends on / relates to as ReferenceElement(see Instantiation of Components)

Accessory Instances
Accessory Instances

The illustration above shows a single accessory that is associated with two reference elements. In cases where the variance control mechanisms are not yet defined1 completely, the condition of existence of the reference elements has implications for the accessory.

An accessory can only exist if all of its ReferenceElements exist, too. However, the existence of all ReferenceElements does not automatically imply the existence of the accessory. Additional constraints may apply, whereby the accessory the can only exist if all ReferenceElements exist and the additional constraints are met.
Grommet with Individual Wire Sealing
Grommet with Individual Wire Sealing

An example for such case are elaborately sealed grommets for improved waterproofing. Each wire passing through the grommet requires a special individual seal. In this case, each seal is an accessory for both the wire and the grommet to the same extent. In concrete variants of the harness, only if a specific wire exists the corresponding seal is required. However, the association to the grommet is equally relevant, as it defines the position of the seal on the wire and without the grommet the seal is also without purpose.


  1. For example not all elements have a specific VariantConfiguration or not all OccurrenceOrUsage are controlled by modules or harness configurations. ↩︎

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