i'm trying to generate and acquire signals for a study using a DT9857E box, so i wrote a short code(using matlab and the DAQ Toolbox) 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 an output channel to an input channel, the same output signal or at least likely was expected to be acquired.

## Question

## G_M

Hello,

i'm trying to generate and acquire signals for a study using a DT9857E box, so i wrote a short code(using matlab and the DAQ Toolbox) 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 an output channel to an 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.

Thanks for your reply :)

I also attached a matlab file with the code if one may want to reproduce these results.

testOutput.m

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