I have one function code in which initially pressure values recorded in voltage and converted into pressure values by using formula. I want to store these calculated values.

function getdata_2021_07_28(src,event,datapoints_event,datapoints_liveplot,ai,data,Fs)

% s.ScansAvailableFcn = @(src,event) dataCapture(src, event, capture, hGui);

% dataCapture(src, ~, c, hGui)

% s.ScansAvailableFcn = @(src,event) getdata2(src,event,datapoints_event,datapoints_liveplot,data);

% getdata2(src,~,datapoints_event,datapoints_liveplot,data)

global olddata

global data

[eventData, eventTimestamps] = read(src, src.ScansAvailableFcnCount, ...

'OutputFormat', 'Matrix');

newdata(:,1) = eventTimestamps; % timestamps

newdata(:,2:length(ai)+1) = eventData;

% Add the time stamp and the data values to data. To write data sequentially,

data=[data; newdata];

if length(olddata)<datapoints_liveplot

olddata=[olddata; newdata];

else

olddata=[olddata(datapoints_event+1:end,:) ; newdata];

end

% plot(olddata(:,1) ,olddata(:,2:length(ai)+1))

% for i=1:length(ai)

% leg{i} = ['ai' num2str(ai(i)) '=' num2str(mean(newdata(:,i+1))) ' V'];

% end

% legend(leg,'FontSize',14,'Location','NorthOutside','Orientation','Vertical');

Time(:,1)=olddata(:,1);

P1=olddata(:,2);

% (0.2-1.3) 0.9720 , 3.01791

% P1=1.0186+(0.275*P1)-(0.275*3.9777);

P1=0.2+(0.275*P1)-(0.275*1);

P2=olddata(:,3);

% (0.1-1.3) 1.1399, 4.481224

% P2=1.1635+(0.3*P2)-(0.3*4.5462);

P2=0.1+(0.3*P2)-(0.3*1);

P3=olddata(:,4);

%(0.1-2) 1.0558, 3.81739

% P3=1.0798+(0.475*P3)-(0.475*3.0622);

P3=2+(0.475*P3)-(0.475*5);

P4=olddata(:,5);

%(0-150)

P4=(31.25*P4)-(31.25);

PMTX(:,1)=Time(:,1);

PMTX(:,2)=P1;

PMTX(:,3)=P2;

PMTX(:,4)=P3;

PMTX(:,5)=P4;

% figure;hold on

% pp1=plot(Time(:,1),P1(:,1)); M1="P_tank";

% pp2=Plot(Time(:,1),P2(:,1)); M2="P_Discharge";

% pp3=Plot(Time(:,1),P3(:,1)); M3="P_Suction";

%

% % legend([pp1,pp2,pp3], [M1, M2,M3]);

% % hold off

% % plot(Time(:,1),[P1(:,1) P2(:,1) P3(:,1)])

% hold on

% yyaxis left

% ylabel('Pressure')

hold on

plot(Time(:,1),P1(:,1),Time(:,1),P2(:,1),Time(:,1),P3(:,1),Time(:,1),P4(:,1))

% plot(Time(:,1),P1(:,1),Time(:,1),P2(:,1),Time(:,1),P3(:,1))

% plot(Time(:,1),P1(:,1));

% plot(Time(:,1),P1(:,2));

% plot(Time(:,1),P1(:,3));

% yyaxis right

% load count.dat;

% ylable('Flow')

% plot(Time(:,1),P4(:,1))

% hold of

% % leg{i} = ['ai' num2str(ai(i)) '=' num2str(mean(newdata(:,i+1))) ' P'];

%drawnow

legend('Tank Pressure','Suction Pressure','Discharge Pessure','Flow');

xlabel('time [s]')

ylabel('Pressure')

xlim([ min(olddata(:,1)) max(olddata(:,1)) ] )

end

Answer 1

[Sreeram]

Hi Avinash,

I am assuming that the question is about how to save the calculated pressure values to the PC during or after data acquisition.

For permanent storage, the data in PMTX (or any other variable) can be saved to disk using MATLAB’s "save" function for MAT files or "writematrix" to export as CSV. This can be done once acquisition is complete or periodically inside the callback, depending on the specific needs.

Refer to the documentations for more details and examples.

https://www.mathworks.com/help/matlab/ref/save.html

https://www.mathworks.com/help/matlab/ref/writematrix.html