BuildingSystems.Fluid.Actuators.BaseClasses.equalPercentage

# .BuildingSystems.Fluid.Actuators.BaseClasses.equalPercentage

Valve opening characteristics for equal percentage valve

## Information

This function computes the opening characteristics of an equal percentage valve.

The function is used by the model BuildingSystems.Fluid.Actuators.Valves.TwoWayEqualPercentage.

For `y < delta/2`, the valve characteristics is linear. For `y > 3*delta/2` the valve characteristics is equal percentage. In between, a cubic spline is used to ensure that the valve characteristics is once continuously differentiable with respect to `y`.

#### Interface

>     function equalPercentage
>       extends Modelica.Icons.Function;
>       input Real y "Valve opening signal, y=1 is fully open";
>       input Real R "Rangeability, R=50...100 typically";
>       input Real l(min = 0, max = 1) "Valve leakage, l=Kv(y=0)/Kv(y=1)";
>       input Real delta "Range of significant deviation from equal percentage law";
>       output Real phi "Ratio actual to nominal mass flow rate, phi=Cv(y)/Cv(y=1)";
>     end equalPercentage;

## Revisions

- April 11, 2016 by Michael Wetter:
  Corrected wrong hyperlink in documentation for issue 450.
- March 30, 2011 by Michael Wetter:
  Added `zeroDerivative` keyword.
- June 5, 2008 by Michael Wetter:
  First implementation.

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