8 System Connections

8.1 System Function

It is necessary to define system functions and flows required to perform the overall functionality of the system. This is typically conducted before subsystems, components and parts are created. System functions and flows are periodically reviewed and updated after items (subsystems, components, parts) have been created to determine whether all system functions, inputs and outputs have been captured correctly.

The system-level functions of the Vehicle system can be defined using the following steps:

• Select (Right-click) the System name from the Project Explorer viewer
• Select Functions from the right-click menu
• Assign Functions, Flows and Flow Properties in the Functions Editor

The right-click menu on the top-level System item shows: New, System Model, Failure Diagram, Bond Graph, Functions, Requirements, Functional Diagram, Mission Profiles, Maintenance Actions, Cut, Copy, Paste, Delete, End Effect Item, Response Paths, Save to Library, Advanced Properties.

Note on system flow connections: Internal flow connections of the system will be automatically generated by MADE when all components and subsystems in all levels of indenture have been connected. This is represented by a dashed connection in the Functions editor.

Example: the Vehicle System's "Convert" function shows IN FLOWS (Liquid Flow rate checked, Gas Mass flow rate checked, Electrical Voltage checked) mapped via dashed lines to OUT FLOWS (Mechanical-rotational Angular velocity, checked twice for two separate Mechanical-rotational out-flow groups).

8.2 Component to MUX Connections

To establish the system and subsystem connections mentioned in the previous section, subsystems and components in lower LOI (Level of Indenture) need to be connected to the input and output flows i.e. MUX bars of the system.

When a system model is opened, two grey, rectangular bars will appear in the far right and left-hand sides of the system model editor. These are called MUX bars and represent the input and output flows of higher levels of indenture.

Item input and output flows are connected to the MUX bars using the same procedure as connecting other components or subsystems found within the same level of indenture. For example: the top-level "Power Generation" system model editor shows a highlighted functional flow between the Fuel Tank and Diesel Engine — the green arrow on the left side of the Diesel Engine represents the input fuel flow rate into the diesel engine assembly.

The nested "Diesel Engine" editor (one level of indenture down) shows the highlighted input fuel flow arrows on the left MUX bar connected to the Lift Pump component inside the Diesel Engine assembly. The single red line on the right MUX bar represents the output mechanical rotational torque flow of the Diesel engine.

Example connection illustration (Figure 51, "Component-System Connections"):

• Top editor "Power Generation": Fuel Tank (Flow rate, Mass flow rate, Voltage in; Static pressure out) connects to Diesel Engine (Torque out to system OUT); Control Unit (Amplitude out) also connects into Diesel Engine.
• Bottom editor "Diesel Engine" (nested level): Air Filter (Mass flow rate) → Engine (Torque out); Coupling 1 (Angular velocity); Lift Pump, Primary Fuel Filter, Secondary Fuel Filter, Injector Pump (Flow rate chain, Dynamic pressure out); Governor (Linear velocity). Left MUX bar shows incoming Static pressure, Mass flow rate, Voltage, Amplitude; right MUX bar shows the outgoing Torque continuing up to the parent Diesel Engine box, matching the connection made at the higher level.

This illustrates how flows entering/exiting a MUX bar at one level of indenture correspond exactly to the functional connections established one level up, and MADE keeps them synchronized automatically once child components and subsystems are fully connected.