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PolysomeRider/pydaqminimal.py

+"""
+Pydaq - a class that allows easy reading of data
+from a data acquisition card making use of the
+nidaq32.dll. Might be adaptable to the new mx nidaq.
+
+The source for this program
+was a message on www.mail-archive.com/pygtk@daa.com.au/
+msg07496.html, signed Todd G. Gardner - pydaq Jan 2004
+The different comments are mine (Cosmin, august 2004)
+based on the NI-DAQ API function reference
+
+This script makes heavy use of the ctypes module
+that allows direct access to C library functions
+"""
+
+from ctypes import *
+
+# Create instance of traditional nidaq dll
+ni=windll.nidaq32
+
+class pydaq:
+  def __init__(self):
+     """variable declaration"""
+     self.deviceNumber=c_int(1)
+     #the device number is generally 1
+     self.chan=c_int(0)
+     #the channel you're going to listen to
+     self.voltage=c_double(1.0)
+     #the read voltage - a float double value
+     self.pvoltage=pointer(self.voltage)
+     #a pointer to the value returned
+     #this is the output of the AI_VRead function
+     self.gain=c_int(-1)
+     #amplification, -1 means multiplying the signal by 0.5
+     self.num=100 #Number of data points
+     self.sampleRate=c_double(1000)
+     self.max=10.0
+     self.min=-10.0
+     self.bits=16
+
+  def AI_Configure (self, deviceNumber=c_int(1), chan=c_int(0),
+                              inputMode=c_int(0), inputRange=c_int(10), 
+                              polarity=c_int(0), driveAIS=c_int(0)):
+    """
+    configure analog input task
+    by providing values to a card and channel
+    """
+    self.AI_ConfigureStatus = ni.AI_Configure (deviceNumber, chan,
+                                      inputMode, inputRange, polarity, driveAIS)
+    #print "AI_Configure status =", self.AI_ConfigureStatus
+    return self.AI_ConfigureStatus
+    
+  def AI_VRead (self, deviceNumber=c_int(1), chan=c_int(0), 
+                    gain=c_int(-1), pvoltage=pointer(c_double(1.0))):
+    """
+    voltage reading from a device and channel with
+    a certain gain. The results go to an adress, a
+    pointer to that adress is in pvoltage
+    Returns a tuple - status, voltage
+    """
+    self.AO_VReadStatus = ni.AI_VRead (deviceNumber, chan, gain, pvoltage)
+    #print "AI_VRead status =", self.AO_VWriteStatus, "voltage =",pvoltage.contents
+    return self.AO_VReadStatus, pvoltage[0]
+
+  def DAQ_Clear (self, deviceNumber):
+    """
+    Cancels the current DAQ operation and
+    reinitializes the DAQ circuitry.
+    """
+    self.DAQ_Clear_status = ni.DAQ_Clear (self.deviceNumber)
+    return self.DAQ_Clear_status
+
+  def AI_Clear (self, deviceNumber=c_int(1)):
+    """
+    clear the data acquisition task
+    AI_Clear clears the analog input circuitry and
+    empties the analog input FIFO memory.
+    """
+    self.AI_ClearStatus = ni.AI_Clear (self.deviceNumber)
+    #print "AI_Clear status =", self.AI_ClearStatus
+    return self.AI_ClearStatus
+
+if __name__ == '__main__':
+  pd=pydaq()
+  chan = c_int(1)
+  volt = pointer(c_double(0.1))
+  deviceNo=c_int(1)
+
+  print pd.DAQ_Clear(pd.deviceNumber)
+  readtuple = pd.AI_VRead(chan = chan, gain=c_int(10), pvoltage = volt)
+  print readtuple[1]/0.1*2.56 #2.56 is the scale on the spectro
+  print readtuple[1], "volts"
+  print pd.DAQ_Clear(pd.deviceNumber)
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