How read CSV data on MATLAB APP?

I am facing problem with reading csv file data and plottng graph of torque vs speed and other plots on MATLAB app which I developed. How can I solve plotting graph and data reading issue

[file,path,~]=uigetfile('*.csv');
t=fullfile(path,file);
app.A = readtable(t);

classdef app1import < matlab.apps.AppBase

    % Properties that correspond to app components
    properties (Access = public)
        UIFigure                     matlab.ui.Figure
        InducedvoltagevsspeedButton  matlab.ui.control.Button
        AvgPowervsEffButton          matlab.ui.control.Button
        SpeedvsTorquevsPowerButton   matlab.ui.control.Button
        torquevsSpeedButton          matlab.ui.control.Button
        ImportdataButton             matlab.ui.control.Button
        UIAxes4                      matlab.ui.control.UIAxes
        UIAxes3                      matlab.ui.control.UIAxes
        UIAxes2                      matlab.ui.control.UIAxes
        UIAxes                       matlab.ui.control.UIAxes
    end

    
    properties (Access = public)
        Property 
        A    % Description
        
    end


    % Callbacks that handle component events
    methods (Access = private)

        % Code that executes after component creation
        function startupFcn(app)
          
      yyaxis(app.UIAxes,'right')
      app.UIAxes.YLabel.String='Power (kW)';
     % app.UIAxes.YLim = [0 25];
      app.UIAxes.YColor = [1 0 0];   % font colour
        yyaxis(app.UIAxes,'left')
        app.UIAxes.YLabel.String='Torque(Nm)';
     %   app.UIAxes.YLim = [0 100];   
        app.UIAxes.Color = [1 1 0.8];  % plot box colour
       app.UIAxes.XLabel.String='Speed(RPM)'
        app.UIAxes.XGrid = 'on';
        app.UIAxes.YGrid = 'on';
        
        %axes 3
        
        
        end

        % Button pushed function: ImportdataButton
        function ImportdataButtonPushed(app, event)
   [file,path,~]=uigetfile('*.csv');
t=fullfile(path,file);
app.A = readtable(t);
app.A.P_SigmaA_Total_WT1=(app.A.P_SigmaA_Total_WT1)./1000;

app.A.Time=time2num(app.A.Time,"minutes");
app.A.U_SigmaA_Total_WT1=(app.A.U_SigmaA_Total_WT1)./(1.732);
app.A.Eta1_1_Total_WT1=(app.A.Eta1_1_Total_WT1).*(1);

app.A.Speed_1_Total_WT1(ismissing(app.A.Speed_1_Total_WT1)) = 0;
app.A.Torque_1_Total_WT1(ismissing(app.A.Torque_1_Total_WT1)) = 0;
app.A.U_SigmaA_Total_WT1(ismissing(app.A.U_SigmaA_Total_WT1)) = 0;
%Efficiency range 0 to 100% variable table11
app.A = app.A(app.A.Eta1_1_Total_WT1 >= 0 & app.A.Eta1_1_Total_WT1 <= 100,:);


app.A.Eta1_1_Total_WT1(ismissing(app.A.Eta1_1_Total_WT1)) = 0;
app.A.P_SigmaA_Total_WT1(ismissing(app.A.P_SigmaA_Total_WT1)) = 0;
        end

        % Button pushed function: torquevsSpeedButton
        function torquevsSpeedButtonPushed(app, event)
         
                
plot(app.UIAxes2,app.A.Torque_1_Total_WT1,app.A.Speed_1_Total_WT1)
title(app.UIAxes2, 'Speed vs Torque')
xlabel(app.UIAxes2, 'Speed (rpm)')
ylabel(app.UIAxes2, 'Torque(Nm)')
zlabel(app.UIAxes2, 'Z')
 
        end

        % Button pushed function: SpeedvsTorquevsPowerButton
        function SpeedvsTorquevsPowerButtonPushed(app, event)
yyaxis(app.UIAxes,'left')
   
plot(app.UIAxes,[app.A.Speed_1_Total_WT1],[app.A.Torque_1_Total_WT1]);
yyaxis(app.UIAxes,'right')

plot(app.UIAxes,[app.A.Speed_1_Total_WT1],[app.A.P_SigmaA_Total_WT1]);
title(app.UIAxes, 'Speed vs Torque vs Power')

        end

        % Callback function
        function TorqueEditFieldValueChanged(app, event)

           
        end

        % Button down function: UIAxes
        function UIAxesButtonDown(app, event)
            
        end

        % Button pushed function: AvgPowervsEffButton
        function AvgPowervsEffButtonPushed(app, event)
            
  
 % Set the Table size for Motor and Temperature csv file
%TimenewT=app.Temp(app.Temp.Time1 >= 500 & app.Temp.Time1 <= 700,:);

%TimenewM = app.A(app.A.Time >= 500 & app.A.Time <=700,:);
%TimenewM = TimenewM(TimenewM.Speed_1_Total_WT1 <= 4200,:); % Set Motor Speed
%xy=TimenewM(1:250,:);    %motor performance csv table
%xy1=TimenewT(1:i3,:); 

%plot(app.UIAxes2,[xy.Time],[xy.Speed_1_Total_WT1]);


plot(app.UIAxes3,[app.A.P_SigmaA_Total_WT1],[app.A.Eta1_1_Total_WT1]);
  title(app.UIAxes3, 'Power(kW) vs Efficiency(%)')
xlabel(app.UIAxes3, 'Power(kW)')
ylabel(app.UIAxes3, 'Efficiency(%)')
        end

        % Button pushed function: InducedvoltagevsspeedButton
        function InducedvoltagevsspeedButtonPushed(app, event)
            
            plot(app.UIAxes4,[app.A.Speed_1_Total_WT1],[app.A.U_SigmaA_Total_WT1 ])
            title(app.UIAxes4, 'Speed(RPM) vs Induced Voltage(V)')
xlabel(app.UIAxes4, 'Speed (RPM)')
ylabel(app.UIAxes4, 'Induced voltage(V)')
        end
    end

    % Component initialization
    methods (Access = private)

        % Create UIFigure and components
        function createComponents(app)

            % Create UIFigure and hide until all components are created
            app.UIFigure = uifigure('Visible', 'off');
            app.UIFigure.Position = [100 100 640 480];
            app.UIFigure.Name = 'MATLAB App';

            % Create UIAxes
            app.UIAxes = uiaxes(app.UIFigure);
            title(app.UIAxes, 'Title')
            xlabel(app.UIAxes, 'Torque')
            ylabel(app.UIAxes, 'Speed')
            zlabel(app.UIAxes, 'Z')
            app.UIAxes.XGrid = 'on';
            app.UIAxes.XMinorGrid = 'on';
            app.UIAxes.YGrid = 'on';
            app.UIAxes.YMinorGrid = 'on';
            app.UIAxes.ButtonDownFcn = createCallbackFcn(app, @UIAxesButtonDown, true);
            app.UIAxes.Position = [363 287 266 194];

            % Create UIAxes2
            app.UIAxes2 = uiaxes(app.UIFigure);
            title(app.UIAxes2, ' Torque vs Speed')
            xlabel(app.UIAxes2, 'Torque(Nm)')
            ylabel(app.UIAxes2, 'Speed (rpm)')
            zlabel(app.UIAxes2, 'Z')
            app.UIAxes2.XGrid = 'on';
            app.UIAxes2.XMinorGrid = 'on';
            app.UIAxes2.YGrid = 'on';
            app.UIAxes2.YMinorGrid = 'on';
            app.UIAxes2.Position = [40 297 247 184];

            % Create UIAxes3
            app.UIAxes3 = uiaxes(app.UIFigure);
            title(app.UIAxes3, 'Power vs Efficiency')
            xlabel(app.UIAxes3, 'Power (kW)')
            ylabel(app.UIAxes3, 'Efficiency(%)')
            zlabel(app.UIAxes3, 'Z')
            app.UIAxes3.XMinorGrid = 'on';
            app.UIAxes3.YMinorGrid = 'on';
            app.UIAxes3.Position = [1 43 300 215];

            % Create UIAxes4
            app.UIAxes4 = uiaxes(app.UIFigure);
            title(app.UIAxes4, 'Speed vs Induced voltage')
            xlabel(app.UIAxes4, 'Speed (RPM)')
            ylabel(app.UIAxes4, 'Induced voltage (V)')
            zlabel(app.UIAxes4, 'Z')
            app.UIAxes4.XGrid = 'on';
            app.UIAxes4.XMinorGrid = 'on';
            app.UIAxes4.YGrid = 'on';
            app.UIAxes4.YMinorGrid = 'on';
            app.UIAxes4.Position = [311 43 318 215];

            % Create ImportdataButton
            app.ImportdataButton = uibutton(app.UIFigure, 'push');
            app.ImportdataButton.ButtonPushedFcn = createCallbackFcn(app, @ImportdataButtonPushed, true);
            app.ImportdataButton.Position = [242 257 100 22];
            app.ImportdataButton.Text = 'Import data';

            % Create torquevsSpeedButton
            app.torquevsSpeedButton = uibutton(app.UIFigure, 'push');
            app.torquevsSpeedButton.ButtonPushedFcn = createCallbackFcn(app, @torquevsSpeedButtonPushed, true);
            app.torquevsSpeedButton.Position = [60 257 103 22];
            app.torquevsSpeedButton.Text = 'torque vs Speed';

            % Create SpeedvsTorquevsPowerButton
            app.SpeedvsTorquevsPowerButton = uibutton(app.UIFigure, 'push');
            app.SpeedvsTorquevsPowerButton.ButtonPushedFcn = createCallbackFcn(app, @SpeedvsTorquevsPowerButtonPushed, true);
            app.SpeedvsTorquevsPowerButton.Position = [401 257 158 22];
            app.SpeedvsTorquevsPowerButton.Text = 'Speed vs Torque vs Power';

            % Create AvgPowervsEffButton
            app.AvgPowervsEffButton = uibutton(app.UIFigure, 'push');
            app.AvgPowervsEffButton.ButtonPushedFcn = createCallbackFcn(app, @AvgPowervsEffButtonPushed, true);
            app.AvgPowervsEffButton.Position = [98 10 106 22];
            app.AvgPowervsEffButton.Text = 'Avg Power vs Eff';

            % Create InducedvoltagevsspeedButton
            app.InducedvoltagevsspeedButton = uibutton(app.UIFigure, 'push');
            app.InducedvoltagevsspeedButton.ButtonPushedFcn = createCallbackFcn(app, @InducedvoltagevsspeedButtonPushed, true);
            app.InducedvoltagevsspeedButton.Position = [418 10 152 22];
            app.InducedvoltagevsspeedButton.Text = 'Induced voltage vs speed';

            % Show the figure after all components are created
            app.UIFigure.Visible = 'on';
        end
    end

    % App creation and deletion
    methods (Access = public)

        % Construct app
        function app = app1import

            % Create UIFigure and components
            createComponents(app)

            % Register the app with App Designer
            registerApp(app, app.UIFigure)

            % Execute the startup function
            runStartupFcn(app, @startupFcn)

            if nargout == 0
                clear app
            end
        end

        % Code that executes before app deletion
        function delete(app)

            % Delete UIFigure when app is deleted
            delete(app.UIFigure)
        end
    end
end

Answer 1

[Cris LaPierre]

The snippet you have shared is working just fine. It is later on in your code that something unexpected is happening.

This line of code is deleting every row in your table A

app.A = app.A(app.A.Eta1_1_Total_WT1 >= 0 & app.A.Eta1_1_Total_WT1 <= 100,:);

This is because all values of app.A.Eta1_1_Total_WT1 are negative, so nothing matches the criteria. Since app.A is now empty, the plot command is working, but there is nothing to plot.

As an aside, since you have already set up your title and axes labels in the app designer canvas, it is not necessary to include code for this in your callback function.

Commenting that line out gives me the following result.

Another aside. Since I didn't have the Predictive Maintenance Toolbox installed, I have replaced the time2num function with minutes. It seems to accomplish the same thing, with the added benefit that minutes is included in MATLAB.

app.A.Time=minutes(app.A.Time);