monochromation

Figure 13: Model: wrapped block class diagram (software engineering view) for the entire monochromation beam ("logical") stage.

Figure 13: Model: wrapped block class diagram (software engineering view) for the entire monochromation beam ("logical") stage.

Includes deeply nested motorised motion stages of the monochromator's goniometer. Only block «wrapper» Components throughout (no «part wrapper» Components are used), since all blocks are designed for this monochromation context only, no reuse in other assemblies is intended, except for the reused motion stage blocks, which are not yet separately wrapped here. To include content specific to each motion stage part they would need to be wrapped in individual «part wrapper» Component.

Figure 12: Model: UML2 composite structure diagram of the monochromator stage assembly with motorised goniometer rotation, tilt, and translation stages, which are driven by encoded devices.

Figure 12: Model: UML2 composite structure diagram of the monochromator stage assembly with motorised goniometer rotation, tilt, and translation stages, which are driven by encoded devices.

Although named after the motorised, controlled values, these are still only the physical blocks. In fact, the upper motion stages will move (they rotate) when the rotating device of the lowest stage (mom) is activated, even though the controlled variables of the upper stages are not even driven. This illustrates an important difference between a low-level logical device view and a physical block view with geometry and relative assembly.

Figure 10: Model: UML2 composite structure diagram for the monochromation beam stage of the neutron diffractometers of the OPAL NBIs.

Figure 10: Model: UML2 composite structure diagram for the monochromation beam stage of the neutron diffractometers of the OPAL NBIs.

Shows beam-centric organisation of the system dictated by neutron flow ports (as opposed to assembly-centric organisation). The monochromator shield assembly is screwed to a concrete floor, the monochromator assembly (including goniometer) rotates with a monochromator shield drum assembly (which is partly inside and partly outside of the fixed monochromator shield assembly), and the beam passes through both “fixed” and “moveable” parts. The use of flowports helps to organise the model according to the logic of the beam. Note the difficulty in reflecting the horizontal beam path concisely.

Note also the lack of direction on the typed 'rotates with' and 'is mounted inside' connections compared with the "directed" association names.

Figure 11: Model: UML2 composite structure diagram of the monochromator assembly

Figure 11: Model: UML2 composite structure diagram of the monochromator assembly

Corresponds roughly to the view from above (the UML diagram can only at best indicate topology, not geometry).

Note also the lack of direction on the typed 'rotates with' and 'is mounted inside' connections compared with the "directed" association names. Compare with the «fitted» and «mounted» Dependencies, which emphasise the time order of construction (assembly) of the components, i.e., that the supplier must exist before the client.
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