Работа с сигналом от мультиметра Keithley (COM port)

clear all
clc
 
time=2;
count=0;
tic
tt=toc;
% Find a serial port object.
obj1 = instrfind('Type', 'serial', 'Port', 'COM4', 'Tag', '');
 
% Create the serial port object if it does not exist
% otherwise use the object that was found.
 
if isempty(obj1)
    obj1 = serial('COM4');
 else
     fclose(obj1);
     obj1 = obj1(1)
end;    
 
% Connect to instrument object, obj1.
fopen(obj1);
 
while tt<time
    
% Communicating with instrument object, obj1.
 
fprintf(obj1, ':fetch?');
data1 = fscanf(obj1);
 
%fileID = fopen('matrica.txt','w');
% fprintf(fileID,data1);
% fclose(fileID);
 
tt=tt+0.1;
 
end;
 
% Disconnect from instrument object, obj1.
fclose(obj1);

clear all
clc
 
time=2;
count=0;
tic
tt=toc;
% Find a serial port object.
obj1 = instrfind('Type', 'serial', 'Port', 'COM4', 'Tag', '');
 
% Create the serial port object if it does not exist
% otherwise use the object that was found.
 
if isempty(obj1)
    obj1 = serial('COM4');
else
    fclose(obj1);
    obj1 = obj1(1)
end;
 
% Connect to instrument object, obj1.
fopen(obj1);
 
t = 0; % начальные занчения
D = 0;
while t(end)<time
    % Communicating with instrument object, obj1.
    fprintf(obj1, ':fetch?');
    data1 = fscanf(obj1);
    
    D(end+1) = str2double(data1); % добавляем значения в массив
    t(end+1) = t(end)+0.1;
 
    plot(t, D) % рисуем
    xlim([0 time])
    drawnow; pause(0.1)
end;
 
% Disconnect from instrument object, obj1.
fclose(obj1);