This function computes the derivative of the opening characteristics of an equal percentage valve.
The function is the derivative of BuildingSystems.Fluid.Actuators.BaseClasses.equalPercentage.
function der_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"; input Real der_y "Derivative of valve opening signal"; output Real der_phi "Derivative of ratio actual to nominal mass flow rate, dphi/dy"; end der_equalPercentage;
zeroDerivative
keyword in function that calls this function.