How to update a graph with timer ?

I have a gui, where I want to update the values ​​of an analog sensor in PIC the data is already read updated but when generating the graph it marks an error which is the following:

Error while evaluating TimerFcn for timer 'timer-26'

Not enough input arguments.

My timer function is the following:

% --- Executes just before usbGuide is made visible.

function usbGuide_OpeningFcn(hObject, eventdata, handles, varargin)

% This function has no output args, see OutputFcn.

% hObject handle to figure

% eventdata reserved - to be defined in a future version of MATLAB

% handles structure with handles and user data (see GUIDATA)

% varargin command line arguments to usbGuide (see VARARGIN)

% Choose default command line output for usbGuide

handles.output = hObject;

% Update handles structure

guidata(hObject, handles);

clc

global m_timer_daq

time = 0.1;

tasks = 100;

m_timer_daq = timer('StartDelay', 0, ...

'ExecutionMode', 'fixedRate');

m_timer_daq.Period = time;

m_timer_daq.TasksToExecute = tasks;

m_timer_daq.StartFcn = {@start_timer_callback, 'My start message'};

m_timer_daq.TimerFcn = @timerDAQ_callback_1;

%m_timer_daq.StartFcn = @(x,y)tic; global rawCurrent; rawCurrent=0;

m_timer_daq.StopFcn = @(x,y)toc;%delete(m_timer_daq);

%%plot(handles.axes1,salida_f);

% UIWAIT makes usbGuide wait for user response (see UIRESUME)

% uiwait(handles.figure1);

function timerDAQ_callback_1(obj, event,handles)

obj.UserData = obj.UserData + 1;

global ctu

global salida_f

ctu=ctu+1

disp(salida_f)

plot(handles.axes1,salida_f);

function start_timer_callback(obj, event, text_arg,handles)

global ctu

ctu=0;

global salida_f

time = 0;

txt1 = ' event occurred at ';

txt2 = text_arg;

event_type = event.Type;

event_time = datestr(event.Data.time);

msg = [event_type txt1 event_time];

disp(msg)

disp(txt2)

tic

% --- Outputs from this function are returned to the command line.

function varargout = usbGuide_OutputFcn(hObject, eventdata, handles)

% varargout cell array for returning output args (see VARARGOUT);

% hObject handle to figure

% eventdata reserved - to be defined in a future version of MATLAB

% handles structure with handles and user data (see GUIDATA)

% Get default command line output from handles structure

varargout{1} = handles.output;

Answer 1

[Geoff Hayes]

Hi @Alan Martínez - the default timer function callback signature takes two inputs only. You are using that default definition here

m_timer_daq.TimerFcn = @timerDAQ_callback_1;

but you have defined a timer callback function with three input parameters

function timerDAQ_callback_1(obj, event,handles)

and so the error message of there "not being enough input parameters" makes sense: the default definition is passing two, but your signature expects three. If you want to pass a custom (third) parameter into your callback, you need to do that when you assign the callback to your timer. Try the following

m_timer_daq.TimerFcn = {@timerDAQ_callback_1, hObject}

Since I am using hObject (the figure/GUI handle) instead of handles then you need to change your callback timer code to

function timerDAQ_callback_1(obj, event, hFigure)
handles = guidata(hFigure);
obj.UserData = obj.UserData + 1;
global ctu
global salida_f
ctu=ctu+1
disp(salida_f)
plot(handles.axes1,salida_f);

I do this because when you pass handles as a parameter to your timer callback, it is a copy of the handles structure only. So any changes to this object will not persist outside of the callback function (though you aren't making any changes anyway so I suppose it doesn't matter).

Also, consider removing the global parameters. I see that you are using them between the start and DAQ callback functions. Just save them to the handles structure instead.

Oh - I see that you will have the same problem with the start timer callback. You need to change that as well:

m_timer_daq.StartFcn = {@start_timer_callback, 'My start message', hObject};

and

function start_timer_callback(obj, event, text_arg, hFigure)
handles = guidata(hFigure);
handles.ctu = 0;
handles.salida_f = 0;       % is this correct? salida_f is never assigned...
guidata(hFigure, handles);  % save the updated handles structure
time = 0;
txt1 = ' event occurred at ';
txt2 = text_arg;
event_type = event.Type;
event_time = datestr(event.Data.time);
msg = [event_type txt1 event_time];
disp(msg)
disp(txt2)
tic

Then use handles in the timerDAQ_Callback to get the ctu and salida_f (which never appears to be set).