Generate and acquire signals with a DT9857E box using Matlab

Hello,

i'm trying to generate and acquire signals for a study using a DT 9857E box, so i wrote a short code to test wether the result could be satisfying or not. The code is written this way:

clear all, clc, close all
s = daq("dt");
fAbtast = 50e3;
s.Rate = fAbtast; %1000;
BoxName = 'DT9857E-16(00)';
addoutput(s,BoxName, '0', 'Voltage');
addinput(s,BoxName,'0', 'Voltage');

fIn = 1e3;
t = 0:1/fAbtast:1-1/fAbtast;
x = sin(2*pi*fIn*t);

Output_data = x'*1.2;
Input_data = readwrite(s, Output_data);
figure
time_vec = seconds(Input_data.Time);
plot(time_vec, Output_data)
hold on
plot(time_vec, Input_data.Variables)
hold off
grid on
legend(["Output Signal","Acquired Signal"])

The result looks this way:

Any Idea on why the acquired signal does look that way? Since i just connected the output channel to the input channel, the same output signal or at least likely was expected to be acquired.

I even try to reproduce the example in the following matlab documentation: Simultaneously Acquire Data and Generate Signals - MATLAB & Simulink - MathWorks Deutschland

but the result did not look great:

%% Example from Matlab's documentation
% A session has been already defined
output = cos(linspace(0,2*pi,1000)');

data1 = readwrite(s, output);

figure
plot(output);
hold on
plot(data1.Variables);
ylabel("Voltage (V)") 
%title("Acquired Signal");
legend(["Output Data","Acquired Signal"])

below is an enlarged view of the acquired signal

Any suggestion to fix this will be greatly appreciated.

Answer 1

[Sulaymon Eshkabilov]

It is all about DAQ

DT9857E issue.

Once we had also the same issue - a kind of exponential decay. So far, I remember what we did was to detrend the acquired data. Also, you can try to use a different channel of DT to collect data.

All the best.

[Galvani]

Thanks for the hint!

[Sulaymon Eshkabilov]

Welcome! Thumbs Up, please!

[Galvani]

The idea of detrending the acquired data or changing channel did not work. Since the shape of acquired signal is not the expected one, detrend does not help that much. I guess you may have done something else also to fix the issue :)

But again, thanks for your reply!

[Sulaymon Eshkabilov]

Most welcome! Glad to help!

[Galvani]

Further suggestions will be appreciated, my questions are still open :)

[Thibaut]

Hi!

I am facing the same issue here. Did you find a way to fix it? :)

[Galvani]

Hi @Thibaut,

You will need to revert back to DT Open Layers v7.8.2.

Begin within MATLAB to uninstall the 'Data Acquisition Toolbox Support Package for Data Translation Hardware' via the Add-On Manager.

Open your Windows ->Control Panel->Programs and Features showing the Data Translation software and version column, and uninstall all DT Open Layers Software( programs with DT Open Layers as Publisher)

Reboot your system and install DT Open Layers v7.8.2. Make sure that the previous installed version are no more on your system.

Finally open MATLAB and reinstall the 'Data Acquisition Toolbox Support Package for Data Translation Hardware' via the Add-On Manager.

Everything should normaly be fine from now on!

Regards,

Galvani

[Thibaut]

Brilliant !

Thanks a lot mate. I've simply followed the procedure you've shared and everything works fine now :)