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Humidifierblock and its embedded Internal Block Diagram (IBD):
It's worth pausing here to try to understand exactly what's going on.
Firstly, note that the block
WaterTank is NOT a physical block, it is merely a "computation block" for tracking the volume of water in a water tank, which information is used by the StateMachine
ControlSM within block
Control (namely it switches the entire system off if the water level gets too low).
Similarly, the block
VaporGenerationPlant is NOT a physical block, it is a "computation block" for tracking the generation of vapor, depending on both the power of a cooling safety fan and a water heater.
Neither the fan nor the heater are explicitly modelled. There is also no explicit modelling of the provision of water from a physical water tank to a physical vapor generation plant. All that happens is that values (only) representing and tracking physical quantities are "shunted" around. It's quantity signal flow, NOT physical interaction.
Note also that there are three StateMachines
HeaterControlSM. We'll look at these in more detail next, but for now just note that the
UsageControlSM acts as a switch across the entire system, mediated by
ControlSM (which may directly influence the fan and indirectly also the heater) according to the tank's
WaterVolume level and the
It's not 100% clear whether there is a physical vapor generation plant and physical heater separate from a physical water tank (such as for a large commercial humidifier), or whether the heater simply acts directly on the water tank (such as for a small domestic humidifier). It is assumed here that they are indeed physically separate.
See that Connector from
oVapor Port on the
vGP:VaporGenerationPlant to the
iConsumption Port on the
wt:WaterTank? It's not carrying physical vapor back into a water tank! It's just conveying information about the quantity
VaporRate_mL_per_h (as was generated by the vapor generation plant).
We're going to start our journey through the
WaterTank, because it helps us anchor the Units.