Use of timer: what's the code to indicate that its period of time is expired?

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Umberto
Umberto 2013-4-3
I created a timer with a period of 30 seconds: the program has to execute some tasks if this period is passed. How do i write the code for expressing the fact that the period is passed?

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回答（2 个）

Doug Hull
Doug Hull 2013-4-3
编辑：Doug Hull 2013-4-3
It is not clear what you are asing, but this is a primer on timers.
video
  1 个评论
Umberto
Umberto 2013-4-4
I didnt't find the answer. Here is my code
V = xlsread('data.xls', 1, 'C2:C1002'); %import data from Excel
t = timer('Period', 30, 'TimerFcn', @(~,~)calculate(V, g, n, Vmin, Vmax));
function calculate(V, g, n, Vmin, Vmax)
for i=1:n
if V(i) < Vmin
start(t);
if %30 seconds have passed
V(i) = V(i)+ g;
end
elseif V(i) > Vmax
start(t);
if %30 seconds have passed
V(i) = V(i)- g;
end
elseif (V(i) >= Vmin && V(i) <= Vmax)
stop(t);
end
end
how do I express in code the sentence "30 seconds have passed"?

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Sean de Wolski
Sean de Wolski 2013-4-4
One thing you could be do would be to toc a tic that was started earlier. However, the best approach would be to get the InstantPeriod from the timer object
function timerNSeconds
T = timer('Period',10,... %period
'ExecutionMode','fixedRate',... %{singleShot,fixedRate,fixedSpacing,fixedDelay}
'BusyMode','drop',... %{drop, error, queue}
'TasksToExecute',2,...
'StartDelay',0,...
'TimerFcn',@(src,evt)tfcn(src,evt,pi),...
'StartFcn',[],...
'StopFcn',[],...
'ErrorFcn',[]);
start(T);
end
function tfcn(src,evt,piapprox)
pause(10) %comment this line to have it not exceed
pi
if get(src,'InstantPeriod') > 10
disp('Period exceeded 10');
end
end
Uncomment the pause to see it working with not exceeding the 10s.
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Umberto
Umberto 2013-4-12
But if I pass src to calculate() then why I get the "Undefined function or variable 't'" message?
Sean de Wolski
Sean de Wolski 2013-4-12
Because you don't pass t!!!! You've renamed it to src even though it is the same thing. You call it t instead if you wish; it's just a good programming practice to call the handle of the source object of a callback src or similar.

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