#Acq_IncClk.py

# This is a near-verbatim translation of the example program
# C:\Program Files\National Instruments\NI-DAQ\Examples\DAQmx ANSI C\Analog In\Measure Voltage\Acq-Int Clk\Acq-IntClk.c

import ctypes
import numpy
from pylab import *

nidaq = ctypes.windll.nicaiu # load the DLL

##############################
# Setup some typedefs and constants
# to correspond with values in
# C:\Program Files\National Instruments\NI-DAQ\DAQmx ANSI C Dev\include\NIDAQmx.h

# the typedefs
int32 = ctypes.c_long
uInt32 = ctypes.c_ulong
uInt64 = ctypes.c_ulonglong
float64 = ctypes.c_double
TaskHandle = uInt32

# the constants
DAQmx_Val_Cfg_Default = int32(-1)
DAQmx_Val_Volts = 10348
DAQmx_Val_Rising = 10280
DAQmx_Val_FiniteSamps = 10178
DAQmx_Val_GroupByChannel = 0
##############################

def CHK(err):
    """a simple error checking routine"""
    if err < 0:
        buf_size = 100
        buf = ctypes.create_string_buffer('\000' * buf_size)
        nidaq.DAQmxGetErrorString(err,ctypes.byref(buf),buf_size)
        raise RuntimeError('nidaq call failed with error %d: %s'%(err,repr(buf.value)))

# initialize variables
taskHandle = TaskHandle(0)
max_num_samples = 1000
data = numpy.zeros((max_num_samples,),dtype=numpy.float64)

# now, on with the program
CHK(nidaq.DAQmxCreateTask("",ctypes.byref(taskHandle)))
CHK(nidaq.DAQmxCreateAIVoltageChan(taskHandle,"Dev1/ai0","",
                                   DAQmx_Val_Cfg_Default,
                                   float64(-10.0),float64(10.0),
                                   DAQmx_Val_Volts,None))
CHK(nidaq.DAQmxCfgSampClkTiming(taskHandle,"",float64(10000.0),
                                DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,
                                uInt64(max_num_samples)));
CHK(nidaq.DAQmxStartTask(taskHandle))
read = int32()
CHK(nidaq.DAQmxReadAnalogF64(taskHandle,max_num_samples,float64(10.0),
                             DAQmx_Val_GroupByChannel,data.ctypes.data,
                             max_num_samples,ctypes.byref(read),None))
print "Acquired %d points"%(read.value)

if taskHandle.value != 0:
    nidaq.DAQmxStopTask(taskHandle)
    nidaq.DAQmxClearTask(taskHandle)

plot(data)
show()

q = raw_input('Enter a file name to save this data or just press enter to exit :')
q.strip()
if q :
    f = file(q, 'w')
    for b in data :
        f.write(str(b)+'\n')
    f.close()