how to output continuous signal using usb6008

Question

mado 2014-3-24

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/122891-how-to-output-continuous-signal-using-usb6008

回答： Julian 2016-11-4

i need your help to use ni usb6008 to output analog signal , the continuous signal is the control signal from PID controller, i used timer but i don't why it isn't working i used this code

      % %%get connected devices
   d = daq.getDevices
   %create session 
    s = daq.createSession('ni')
   s1= daq.createSession('ni')
    %add analog channel  s.addAnalogInputChannel('ID',channel num, 'measurement type')
   % s.addAnalogInputChannel('Dev1',0:3, 'Voltage')%irradiance
    s.addAnalogInputChannel('Dev1','ai0', 'Voltage')%irradiance
    s.addAnalogInputChannel('Dev1','ai1', 'Voltage')%Temperature
    s.addAnalogInputChannel('Dev1','ai2', 'Voltage')%current
    s.addAnalogInputChannel('Dev1','ai3', 'Voltage')%voltage
   % s.addAnalogInputChannel('Dev1','ai3', 'Voltage')%Temperature
   %set(s.Channels,'InputType','SingleEnded')
  %set(s.Channels,'Range',[-10 10])
     %s.addAnalogInputChannel('Dev1','ai6', 'Voltage')%Temperature
AO=s1.addAnalogOutputChannel('Dev1', 'ao0', 'Voltage')
% set rate of scan  1000 scans/second ,  run for 30 seconds
   s.Rate=1000;
  s.DurationInSeconds =10
  v.TerminalConfig = ' Differential';
  %v.TerminalConfig = ' SingleEnded';
  %_____________________________
  %aquire data and process
  lh = s.addlistener('DataAvailable', @plotData);
  %store data
  %h = s.addlistener('DataAvailable', @storedata);
  % Analog Output 
   % duty cycle control signal x amplification 
   %for i=1:5
  e= 18 - Vref
  %end
  IE=sum(e); %Integral of  Error
      % C = pid(20,10,0,'InputName','e','OutputName','u')  % calculate control signal of pid 
  u=C*er 
  for i=1:length(u)
          t = timer('TimerFcn', ' putsample(AO,u)',...
                'StartDelay',0.2);
          start(t)
    end
s.startBackground()
   s.wait()
 delete (lh)
 s.release()

it gives me error message

Error while evaluating TimerFcn for timer 'timer-1840'

Undefined function 'putsample' for input arguments of type 'daq.ni.AnalogOutputVoltageChannel

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Answer 1

Walter Roberson 2014-3-24

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https://ww2.mathworks.cn/matlabcentral/answers/122891-how-to-output-continuous-signal-using-usb6008#answer_130103

putsample() is only for the legacy interface.

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mado 2014-3-24

in other questions i used singlescan but i want to output control signal which can't be one value , is there any solution ?is it available or should i switch back to legacy interface?

Walter Roberson 2014-3-24

I will have to look at this later.

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Answer 2

Julian 2016-11-4

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/122891-how-to-output-continuous-signal-using-usb6008#answer_241917

Ok, this answer is quite late, and not only focused on your actual code, but as I had a similar question just a short time ago, here's my answer:

The NI-USB6008 doesn't support clocked operations. That means you must trigger by yourself when you want to output a signal. If the need of real continuity and speed are not too important you can use a loop or something like that. If you really like to output continuously, it's better to use a DAQ Device that supports Hardware Triggering. Then you can pre-buffer your signals, can controll the output rate etc., in the background or in the foreground.