Exponentials

block Exponentials "Generate a rising and falling exponential signal"
    parameter Real outMax = 1 "Height of output for infinite riseTime"
        annotation (Dialog(groupImage = "modelica://Modelica/Resources/Images/Blocks/Sources/Exponentials.png"));
    parameter SI.Time riseTime(min = 0, start = 0.5) "Rise time";
    parameter SI.Time riseTimeConst(min = Modelica.Constants.small) = 0.1 "Rise time constant; rising is defined as outMax*(1-exp(-riseTime/riseTimeConst))";
    parameter SI.Time fallTimeConst(min = Modelica.Constants.small) = riseTimeConst "Fall time constant";

    extends Interfaces.SignalSource;

protected
    Real y_riseTime;
equation
    y = offset + (if time < startTime then 0 else if time < startTime + riseTime then outMax * (1 - Modelica.Math.exp(-(time - startTime) / riseTimeConst)) else y_riseTime * Modelica.Math.exp(-(time - startTime - riseTime) / fallTimeConst));
    y_riseTime = outMax * (1 - Modelica.Math.exp(-riseTime / riseTimeConst));

    annotation (
        Icon(
            coordinateSystem(
                preserveAspectRatio = true,
                extent = {
                    {-100, -100}, 
                    {100, 100}}),
            graphics = {
                Line(
                    points = {
                        {-90, -70}, 
                        {68, -70}},
                    color = {192, 192, 192}), 
                Polygon(
                    points = {
                        {90, -70}, 
                        {68, -62}, 
                        {68, -78}, 
                        {90, -70}},
                    lineColor = {192, 192, 192},
                    fillColor = {192, 192, 192},
                    fillPattern = FillPattern.Solid), 
                Line(points = {
                    {-80, -70}, 
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                    {-74.3, -42.1}, 
                    {-70.8, -27.6}, 
                    {-67.3, -15}, 
                    {-63.7, -4.08}, 
                    {-59.5, 7.18}, 
                    {-55.3, 16.7}, 
                    {-50.3, 26}, 
                    {-44.6, 34.5}, 
                    {-38.3, 42.1}, 
                    {-31.2, 48.6}, 
                    {-22.7, 54.3}, 
                    {-12.1, 59.2}, 
                    {-10, 60}, 
                    {-7.88, 47.5}, 
                    {-5.05, 32.7}, 
                    {-2.22, 19.8}, 
                    {0.606, 8.45}, 
                    {4.14, -3.7}, 
                    {7.68, -14}, 
                    {11.9, -24.2}, 
                    {16.2, -32.6}, 
                    {21.1, -40.5}, 
                    {26.8, -47.4}, 
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                    points = {
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                    lineColor = {192, 192, 192},
                    fillColor = {192, 192, 192},
                    fillPattern = FillPattern.Solid), 
                Line(
                    points = {
                        {-80, 68}, 
                        {-80, -80}},
                    color = {192, 192, 192}), 
                Text(
                    extent = {
                        {-150, -150}, 
                        {150, -110}},
                    textString = "riseTime=%riseTime")}),
        Documentation(info = "<html>\n<p>\nThe Real output y is a rising exponential followed\nby a falling exponential signal:\n</p>\n\n<p>\n<img src=\"modelica://Modelica/Resources/Images/Blocks/Sources/Exponentials.png\"\n     alt=\"Exponentials.png\">\n</p>\n</html>"));
end Exponentials;