ADLM1000 Write to Buffer Downsample then append to file

Question

Matthew Humbert 2021-5-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/832728-adlm1000-write-to-buffer-downsample-then-append-to-file

Hello,

I have an ADLM1000, which is truely a remarkable piece of hardware. The only challenge I have with it is that it records at 100kHz which is too much data for me. I'd like to read from it into a buffer downsample to 100Hz and then append the downsampled values (with timestamps) to a file.

When I run the code below I get the error: "ADALM1000 background operations do not support generation or finite acquisition." Can anyone think of a workaround?

Thank you,

-Matt

%% Start the DAQ session
clear ADISession
close all
daqlist("adi");
ADISession = daq("adi");
addoutput(ADISession, 'SMU1','a','Current');
addinput(ADISession, 'SMU1','a','Voltage');
%addinput(ADISession, 'smu1','b','Voltage');
ADISession.ScansAvailableFcnCount = 10000; % set the scans available to fire 100 times per second Samples at 100kHz so this function will be called every 1000 points or 100 times/second
%% Chrono Ampometry Sequence
fs = ADISession.Rate;        % Sampling rate for chronoampometry
Current = 0.0002; % Amps for constant current up to 200mA
Duration = 5; % Time to record in seconds
T_Chrono = 0:1/fs:Duration;
A_Chrono = ones(1,fs*Duration)*Current;
StartTime = datestr(now,'yyyy-mm-dd_HHMM');
File = strcat('Chrono_',StartTime,'.mat');
Chrono_exp_resample = [];
save(File,'Chrono_exp_resample','-v7.3');
File_Obj = matfile(File,'Writable',true);
ADISession.ScansAvailableFcn = @(src,evt) AverageAndSave(src,evt);
start(ADISession, "Duration",Duration)
write(ADISession,A_Chrono')
while ADISession.Running
    pause(0.5)
    fprintF("While loop: Scans acquired = %d\n", ADISession.NumScansAcquired);
end
%% Close Down the DAQ
clear ADISession
close all
%% Functions at the end!
function AverageAndSave(src,~)
    Chrono = read(src,src.ScansAvailableFcnCount);
    Chrono_exp = retime(Chrono,'regular','mean','SampleRate',100);
    File_Obj.Chrono_exp_resample = [File_Obj.Chrono_exp_resample, Chrono_exp];
end
%% Notes
%https://au.mathworks.com/help/matlab/import_export/load-parts-of-variables-from-mat-files.html
%https://au.mathworks.com/help/daq/acquire-continuous-and-background-data-using-ni-devices.html