PartialMedium.Input* connectors should use Medium. types, not SI.

[bilderbuchi]

Observed problem

I tried to trace a puzzling inconsistency in nominal pressure values in a model.

To demonstrate, e.g. simulate Modelica.Fluid.Examples.PumpingSystem (MSL 4.0.0) with warnings for aliases with conflicting values activated (e.g. OpenModelica -d=aliasConflicts)
I am seeing, among other warnings, this:

Translation Warning
Alias set with conflicting nominal values

• Candidate: pumps.medium.sat.psat(nominal = 1000000.0, confidence number = 9)
• Candidate: pumps.heatTransfer.states[1].p(nominal = 1000000.0, confidence number = 9)
• Candidate: pumps.monitoring.state.p(nominal = 1000000.0, confidence number = 9)
• Candidate: pumps.medium.state.p(nominal = 1000000.0, confidence number = 9)
• Candidate: pipe.flowModel.states[1].p(nominal = 1000000.0, confidence number = 9)
• Candidate: pipe.port_a.p(nominal = 1000000.0, confidence number = 8)
• Candidate: pumps.port_b.p(nominal = 1000000.0, confidence number = 8)
• Candidate: pumps.medium.p(nominal = 100000.0, confidence number = 8)
  => Select value from pumps.medium.p(nominal = 100000.0) for variable: pumps.medium.p

I emphasized the only nominal value that is in disagreement, for pumps.medium.p.

Expected behaviour

Avoid conflicting values that need resolution when using MSL models.

Analysis

I traced this back (I think) to the fact that in Modelica.Media.Interfaces.PartialMedium.BaseProperties here, we have

connector InputAbsolutePressure = input SI.AbsolutePressure
      "Pressure as input signal connector";

which is used to define p for a medium: InputAbsolutePressure p "Absolute pressure of medium";

The difference becomes visible when concrete Medium models (in this case Modelica.Media.Water.StandardWaterOnePhase) define their AbsolutePressure with a nominal value different from SI.AbsolutePressure.

Proposed resolution

I think the connector definition in PartialMedium should use the AbsolutePressure type already available within it (via the extends Modelica.Media.Interfaces.Types;) instead of the one from SI:

connector InputAbsolutePressure = input AbsolutePressure
      "Pressure as input signal connector";

The same approach is probably valid for other SI.-prefixed types used, like InputSpecificEnthalpy. I suspect that could solve a lot of the other present alias conflicts, but I have not done any investigation on that.