Within a machine, its components are usually mounted / mechanically connected in some way. Part2 allows you to express the information, how and where things are mounted.

Let us model a simple example:

A camera is usually built out of a camera body (which we will represent by the image sensor as its most important functional part) and a lens that creates a projection on that sensor.

Using the object types given above, we would get an image sensor object and a lens object located in their specific folders.

As the lens is attached to the outside of the camera body, and in principle can be detached, we will use the HasAttachedComponent Reference to show this relationship between the two objects

Figure 50 – Mechanical Connections with OPC UA References

Browsing this model, we get the information that a lens called “Lens1” is attached to an image sensor called “ImageSensor1”.

Now let us mount an optical filter onto the lens. This can be done using the same modeling approach.

Figure 51 – Mechanical Connections with OPC UA References

Let us assume the image sensor is equipped with an internal infrared filter in front of the actual sensor chip. As this filter is an integral part of the image sensor, there is no need to add it to the model at all, as the image sensor is already in the model.

But maybe we want to make sure that a service guy browsing this model during maintenance work is aware of the presence of that IR filter. Therefore, we can add it to the model, this time using the HasContianedComponent reference expressing that something is an integral, i.e., not easily removable, part of some other component.

Figure 52 – Mechanical Connections with OPC UA References

Maybe if someone later on will have to replace the lens it would be nice to know which mechanical interface (like C-Mount or F-Mount) is used in this assembly.

Part2 allows you to get into more detail by adding additional information layers to the model. To add information about the physical connection types supported by your components you may add objects naming each of this physical interfaces / connection points located at your item.

Figure 53 – Mechanical Connections with OPC UA References

Browsing this model we get the information that there is a lens mount built into the Image sensor. The PhysicalInterface_IS_LensMount Object can hold all information you may need to specify what type of mount this is.

Further browsing shows that Lens1 has two physical connection ports. There is a lens mount on one end and a filter mount on the other.

We also see that the Filter has two filter mounts (on both sides) to be able to stack multiple filters if needed.

During engineering of the system, you may compare the image sensor1 lens mount to the lens1 lens mount to see if the components will fit together.

As this example shows an already mounted lens - as we can see by the HasAttachedComponent reference between image sensor and lens - we will find this information reflected also by the additional information layer of the physical ports. This time we find an IsPhysicallyConnectedTo reference between the two lens mount objects.

The nature of physical ports is that they may be connected or disconnected several times. Therefore, at this level we are only using the IsPhysicallyConnectedTo reference which expresses a somehow weak relation – it is currently physically connected, but this could change at any time. Despite of that, at the component level above you still have the much stronger HasAttachedComponent reference which tells you that this is a connection not intended to be broken during normal operation.