how to output continuous signal using usb6008

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

Answer 1

[Walter Roberson]

putsample() is only for the legacy interface.

[mado]

so how to solve this problem?

[Walter Roberson]

Don't use putsample().

It appears to me that if you do not use putsample() then the matter becomes the same as you have already asked in one of your other questions and so should be resolved there instead of here.

[mado]

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]

I will have to look at this later.

Answer 2

[Julian]

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.