Continuous DAQ with NI USB 6008 and DAQmx

[mhead10]

If I run a while loop (to obtain my DAQ data), the maximum number of times the loop will run is 4. After 4 times, "after start task" is displayed, but then nothing else. Therefore, it seems every time the loops gets stuck on the read function.

Any ideas?

I continue to move around what's inside of the function obtain_value, as well as change # of samples and sampling frequency.

Here is the code I'm referring to:

def obtain_value():
    print 'entered main program'
    CHK(nidaq.DAQmxCreateTask("",ctypes.byref(taskHandle)))
    print ' after create task'
    CHK(nidaq.DAQmxCreateAIVoltageChan(taskHandle,"Dev2/ai0:1","",DAQmx_Val_Cfg_Default,float64(-13.0),float64(13.0),DAQmx_Val_Volts,None))
    print '  after create voltage'
    CHK(nidaq.DAQmxCfgSampClkTiming(taskHandle,"",float64(50),DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,uInt64(max_num_samples))); #(samples/sec/channel)  #ContSamps    
    print '   after clk'
    CHK(nidaq.DAQmxStartTask(taskHandle))
    print '    after start task'
    CHK(nidaq.DAQmxReadAnalogF64(taskHandle,-1,float64(-1),DAQmx_Val_GroupByChannel,data.ctypes.data,max_num_samples,ctypes.byref(read),None)) 
    print '     after read'
    print data
    if taskHandle.value != 0:
        nidaq.DAQmxStopTask(taskHandle)
        nidaq.DAQmxClearTask(taskHandle)   
    print '      end'

i = 0
while i < 5:
    i += 1
    print i
    obtain_value()