function iodaq(samplerate,duration,amplitude,frequency,filename)
% iodaq(samplerate,duration,amplitude,frequency,filename) 
% Data Acquisition with simultaneous Analog Input and Analog Ouput
%  Samples per second for both analog input and analog ouput
%  Duration of test (seconds)
%  Amplitude of sinusoidal signal for analog output (0 to 10 volts)
%  Frequency of sinusoidal signal for analog output
%  Data file name for analog input data
%
% example:
% iodaq(100,10,3,2.5,'mydata1.dat')

% Chris Dillenbeck, Duke University, 7/04, cjd9@duke.edu
% Matthew Sin, Duke University, 11/05, mcs21@duke.edu
% Henri Gavin, Duke University, 11/05, hpgavin@duke.edu

delete(daqfind);     % delete all previous data acquisition settings

points = samplerate*duration;       % number of data points

%Initialize analog input
ai = analoginput('nidaq');          % specify analog input
addchannel(ai, 1:2);                % channels for data acquisition
set(ai,'SampleRate',samplerate)     % samples per second
set(ai,'SamplesPerTrigger',points)  % number of data points
set(ai,'InputType','Differential')  % differential inputs
set(ai,'TransferMode','Interrupts') % transfer data by interrupts

ai.Channel.InputRange = [-10 10];   % input voltage range ... all channels

ai.Channel.ChannelName(1) = 'sensor 1'; % name of sensor 1
ai.Channel.Units(1) = 'Volts';        % the physical units of sensor 1
ai.Channel.SensorRange(1) = [ -5 5 ]; % typical voltage output from sensor
ai.Channel.UnitsRange(1) = [ -5 5 ];  % the physical units corresponding
                                      % to the sensor range levels
                                      
ai.Channel.ChannelName(2) = 'sensor 2'; % name of sensor 2
ai.Channel.Units(2) = 'Volts';        % the physical units of sensor 2
ai.Channel.SensorRange(2) = [ -5 5 ]; % typical voltage output from sensor
ai.Channel.UnitsRange(2) = [ -5 5 ];  % the physical units corresponding
                                      % to the sensor range levels

%Initialize analog output
ao = analogoutput('nidaq',1);         % specify analog output
addchannel(ao,0);                     % channels for analog output
set(ao,'SampleRate',samplerate)       % sample rate for analog output
set(ao, 'TransferMode', 'None')       % cludge!
%ActualRate = get(ao,'SampleRate');
set([ai ao],'TriggerType','Manual')   % start when program starts

ai                      % display properties of analog input
ao                      % display properties of analog output

%Test data
time = [1:points]/samplerate;
analog_out_data = amplitude*sin(2*pi*frequency*time)';

%Output data
putdata( ao , analog_out_data )      % load the analog output data

%Run
start([ao ai])                       % start the analog input/output
trigger([ao ai])                     % trigger analog input/output

%Input data
analog_in_data = getdata(ai);        % get data from the analog input
waittilstop(ao,duration+1)           % wait for analog output to finish

figure(1)                            % plot the data
 plot(time,analog_in_data)
 xlabel('time, sec')
 ylabel('volts')

 chan = get(ai,'Channel');
 idx = chan.Index;
 fp_ai = fopen(filename,'w');        % open analog input data file name
 % save the analog input data
 for p=1:points
     fprintf(fp_ai,' %8.3f', time(p));
     for i = 1:length(idx)
         c = idx{i};                 % curly brackets!
         fprintf(fp_ai,' %14.5e', analog_in_data(p,c));
     end
     fprintf(fp_ai,'\n');
 end
 fclose(fp_ai);

% Discard Variables
delete ([ao ai])
clear [ao ai]

% ----------------------------------------------------- IODAQ