MATLAB Examples (Windows UD)

Hi all,

Here an example Matlab script for linux using a compiled version of the u6.c as shared library to get access to the high level functions like eAIN and eDAC.

Have fun

Andre

 

 

% Andre, March 27, 2012

% Version 1.2

% Tested on 32 bit Ubuntu 10.10 Linux

% Tested with MatLab 7.10.0.499 (R2010a)

 

% Use the higher level u6 functions, like eAIN and eDAC, with ONE LabJack U6.

 

% Loading the u6 library generates quite some warnings, but it looks like

% everything works just fine.

 

clear all;

ljud_Constants;

 

my_reload = 0;

if my_reload ~= 0

   disp( 'unload libraries' );

   unloadlibrary('liblabjackusb');

   unloadlibrary('libu6');

end

 

% Load exodriver, which contains low level functions like read and write

if ~ libisloaded('liblabjackusb')

   disp( 'load labjack library' );

 

   header = '/usr/local/include/labjackusb.h';

   ljlib = '/usr/local/lib/liblabjackusb.so';

   [notfound,warnings]=loadlibrary(ljlib, header);

end

 

% Load u6 library, which contains high level functions like eAIN and eDAC

if ~ libisloaded('libu6')

   disp( 'load u6 library' );

 

   % Created shared libary with the following command:

   % gcc -Wall -g -fPIC -shared /usr/local/lib/liblabjackusb.so -Wl,-soname,libu6.so -o libu6.so u6.c

   u6header = '/home/andre/matlab/u6.h';

   u6ljlib = '/home/andre/matlab/libu6.so';

   [notfound,warnings]=loadlibrary(u6ljlib, u6header);

   % Andre: this loadlibary gives a lot of WARNINGS!!

   % disp( warnings );

end

 

% Show available functions with arguments of both libraries:

% libfunctionsview liblabjackusb

% libfunctionsview libu6

 

% Check LabJack library version:

if calllib( 'liblabjackusb', 'LJUSB_GetLibraryVersion' ) ~= 2.0

   warning( 'This implementation is only tested with library version 2.0' );

end

 

% Check if there is exactly ONE LabJack attached:

if calllib( 'liblabjackusb', 'LJUSB_GetDevCount', LJ_dtU6 ) ~= 1

   error( 'There should be exactly ONE LabJack U6 device attached' );

end

 

% Open the device and verify the returned handle:

handle = calllib( 'liblabjackusb', 'LJUSB_OpenDevice', 1, 0, LJ_dtU6 );

[handle_valid, tmp] = calllib( 'liblabjackusb', 'LJUSB_IsHandleValid', handle );

if ~handle_valid error( 'LabJack handle is invalid' ); end

 

% Get calibration information, required for the ADC and DAC:

[state, tmp, cali] = calllib( 'libu6', 'getCalibrationInfo', handle, [] );

if state ~= 0 error( 'Cannot get calibration info' ); end

 

% Check if the calibration struct contains appropriate data:

if cali.prodID ~= LJ_dtU6 error( 'Calibration struct is invalid' ); end

 

% Get ADC value from AIN0 to AIN14 and Labjack temperature:

for chan=1:15,

   [state, tmp, tmp2, value(chan)] = calllib( 'libu6', 'eAIN', handle, cali, chan-1, 15, 0, LJ_rgBIP10V, 0, 0, 0, 0, 0 );

   if state ~= 0 error( 'Problem getting eAIN' ); end

end

 

fprintf( 'LabJack temperature: %.2fC\n', value(15)-273.15 );

 

fprintf( 'ADC val:  ' );

for chan=1:14,

   fprintf( ' %4.2f', value(chan) );

end

fprintf( '\n' );

 

% Now determine the mean, maximum and minimum for each channel for a number of samples

measure = zeros( 100, 6 ); % number of samples, number of channels

fprintf( 'Collect %d samples for %d ADC inputs (interleaved)\n', size(measure,1), size(measure,2) );

for ii = 1:size(measure,1),

   for chan = 1:size(measure,2),

      [state, tmp, tmp2, measure(ii,chan)] = calllib( 'libu6', 'eAIN', handle, cali, chan-1, 15, 0, LJ_rgBIP10V, 0, 0, 0, 0, 0 );

      if state ~= 0 error( 'Problem getting eAIN' ); end

   end

end

 

fprintf( 'ADC mean: ' );

for chan = 1:size(measure,2),

   fprintf( ' %4.2f', mean(measure( :, chan) ) );

end

fprintf( '\n' );

 

fprintf( 'ADC max:  ' );

for chan = 1:size(measure,2),

   fprintf( ' %4.2f', max(measure( :, chan) ) );

end

fprintf( '\n' );

 

fprintf( 'ADC min:  ' );

for chan = 1:size(measure,2),

   fprintf( ' %4.2f', min(measure( :, chan) ) );

end

fprintf( '\n' );

 

plot(measure);

title( '\bf{\it{LabJack U6 ADC Measurement}}' );

 

legend_str = {};

for chan = 1:size(measure,2),

   legend_str( chan ) = {['AIN ', num2str( chan ) ]};

end

 

legend( legend_str );

xlabel( 'Time [samples]' );

ylabel( 'Amplitude [V]' );

grid on;

 

% Test the DAC by setting 2.55V on DAC 0 and 1.80V on DAC 1

[state, tmp, tmp2] = calllib( 'libu6', 'eDAC', handle, cali, 0, 2.55, 0, 0, 0 );

if state ~= 0 error( 'Problem setting eDAC' ); end

[state, tmp, tmp2] = calllib( 'libu6', 'eDAC', handle, cali, 1, 1.80, 0, 0, 0 );

if state ~= 0 error( 'Problem setting eDAC' ); end

 

% Digital out FIO, set FIO 0 to high, set FIO 2 to low

[state, tmp] = calllib( 'libu6', 'eDO', handle, 0, 1 );

if state ~= 0 error( 'Problem getting eD0' ); end

 

[state, tmp] = calllib( 'libu6', 'eDO', handle, 2, 0 );

if state ~= 0 error( 'Problem getting eD0' ); end

 

% Digital in FIO, get FIO 1 (should be high) and FIO 3 (should be low)

% Asume FIO 0 is connected to FIO 1 and FIO 2 is connected with FIO 3

[state, tmp, fio1] = calllib( 'libu6', 'eDI', handle, 1, 0 );

if state ~= 0 error( 'Problem getting eDI' ); end

if fio1 ~= 1 warning( 'Should be high if connected to FIO 0' ); end

 

[state, tmp, fio3] = calllib( 'libu6', 'eDI', handle, 3, 0 );

if state ~= 0 error( 'Problem with getting eDI' ); end

if fio3 ~= 0 warning( 'Should be high if connected to FIO 2' ); end

 

% All done, close LabJack:

calllib( 'liblabjackusb', 'LJUSB_CloseDevice', handle );

 

fprintf( 'All done!\n' );