MATLAB: Is the lower limit of the TimerPeriod property of instrument objects different from the lower limit of the MATLAB timer object

Instrument Control Toolboxobjectserialtimertimerperiod

Why is the lower limit of the TimerPeriod property of instrument objects different from the lower limit of the MATLAB timer object?

Why can the timer Period from the timer object Matlab can go down to 0.001s and the timer object from the Instrument Control Toolbox only to 0.01s?

The MATLAB timer object has a lower limit of 0.001s but the lower limit of the instrument control toolbox objects and the serial object is 0.01s. Why is this so and how can we obtain a lower limit of 0.001s with the instrument control toolbox objects?

Best Answer

The reason why the Instrument Control Toolbox and the SERIAL object have a Timer Period lower limit of 0.01s is so that the period is not skipped during the operations that are being performed. That is, the TimerPeriod can possibly be skipped if the operation takes more than the timer period. The lower limit of 0.01s safe guards against setting the limit to an unrealistic period.

The lower limit of 0.001s with the timer object is provided but it is not likely that all callback functions can be executed within a period. So there are possibilities that some periods will be missed intermittently.

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Your timer function @axes1.handles is completly invalid, it's no function.

Also the way you start and stop the timer isn't correct, should give you too many errors.

Here's a GUI that I made with GUIDE, the fig file is just one axes and one pushbutton, the m file code is:

function varargout = rottest(varargin)
% ROTTEST M-file for rottest.fig
%      ROTTEST, by itself, creates a new ROTTEST or raises the existing
%      singleton*.
%




%      H = ROTTEST returns the handle to a new ROTTEST or the handle to
%      the existing singleton*.
%
%      ROTTEST('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in ROTTEST.M with the given input arguments.
%
%      ROTTEST('Property','Value',...) creates a new ROTTEST or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before rottest_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to rottest_OpeningFcn via varargin.
%
%      *See GUI Options on GUIDE's Tools menu.  Choose "GUI allows only one
%      instance to run (singleton)".
%
% See also: GUIDE, GUIDATA, GUIHANDLES
% Edit the above text to modify the response to help rottest
% Last Modified by GUIDE v2.5 04-Jun-2011 18:27:20
% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @rottest_OpeningFcn, ...
                   'gui_OutputFcn',  @rottest_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{1})
    gui_State.gui_Callback = str2func(varargin{1});
end
if nargout
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
    gui_mainfcn(gui_State, varargin{:});
end
% End initialization code - DO NOT EDIT
% --- Executes just before rottest is made visible.
function rottest_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 rottest (see VARARGIN)
% Choose default command line output for rottest
handles.output = hObject;
spy %just to put something in the axes so we can see it rotating
MyTimer=timer('TimerFcn',@RotImgFcn,'BusyMode','queue','executionmode','fixedspacing','period',0.5);
%tag the timer and axes to have easy access to their handles
set(MyTimer,'tag','MyTimer')
set(handles.axes1,'tag','MyAxes')
% Update handles structure
guidata(hObject, handles);
% UIWAIT makes rottest wait for user response (see UIRESUME)
% uiwait(handles.figure1);
% --- Outputs from this function are returned to the command line.
function varargout = rottest_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;
% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
MyTimer=timerfind('tag','MyTimer');
MyTimerStatus=get(MyTimer,'Running');
if strcmp(MyTimerStatus,'off')
start(MyTimer)
else
stop(MyTimer)
end
function RotImgFcn(a,b)
%this function does the rotation
camorbit(findall(0,'tag','MyAxes'),1,0,'data',[0 0 1]); 
% --- Executes when user attempts to close figure1.
function figure1_CloseRequestFcn(hObject, eventdata, handles)
% hObject    handle to figure1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% when the user closes the GUI it stops the timer if it is running
% and deletes the timer from memory
MyTimer=timerfind('tag','MyTimer');
MyTimerStatus=get(MyTimer,'Running');
if strcmp(MyTimerStatus,'on')
stop(MyTimer)
end
delete(timerfind('tag','MyTimer')); %delete our timer
%delete(timerfindall) %delete all timer objects
% Hint: delete(hObject) closes the figure
delete(hObject);

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Please read help about functions MATLAB:

quad, quad2d, dblquad, quadgk, quadl, quadv, trapz, triplequad,int

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