old_contents: """
  labview.py is a module to interface with a Windows PC running a LabVIEW
  VI that acquires data with an NI-DAQ.
  
  Using TCP/IP the VI listens for incoming connections. The requesting
  computer sends a message requesting a capture time. The Windows PC
  acquires the data, writes it to file, then uses the WinSCP utility to
  copy the file to /home/dcb/polarimeter/data/YYYY-MM-DD-HHMMSS.csv.
  The requesting computer then loads the file, which contais the time
  and signals of the two channels.
  """
  import socket
  import time
  import numpy as np
  
  socket.setdefaulttimeout(60) # seconds
  
  def acquire(capture_time, IP='155.198.231.92', port=5020):
  	"""Aquires data for capture_time (seconds) via acquisition PC.
  	Returns time, and signals of hannel A and channel B.
  	"""
  	if capture_time <= 0:
  		raise ValueError('capture_time must be greater than zero.')
  
  	sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  	sock.connect((IP, port))
  	sock.send('%.2f\r' % capture_time)
  	assert sock.recv(1024) == 'acquiring'
  	time.sleep(capture_time + 1)
  	filename = sock.recv(1024)
  	assert filename[-3:] == 'csv'
  	sock.close()
  	data = np.loadtxt('data/signals/' + filename, delimiter=',')
  	return (data[:,0], data[:,1], data[:,2])
  
new_contents: """
  labview.py is a module to interface with a Windows PC running a LabVIEW
  VI that acquires data with an NI-DAQ.
  
  Using TCP/IP the VI listens for incoming connections. The requesting
  computer sends a message requesting a capture time. The Windows PC
  acquires the data, writes it to file, then uses the WinSCP utility to
  copy the file to /home/dcb/polarimeter/data/YYYY-MM-DD-HHMMSS.csv.
  The requesting computer then loads the file, which contais the time
  and signals of the two channels.
  """
  import socket
  import time
  import numpy as np
  
  socket.setdefaulttimeout(60) # seconds
  
  def acquire(capture_time, IP='155.198.231.92', port=5020):
  	"""Aquires data for capture_time (seconds) via acquisition PC.
  	Returns time, and signals of hannel A and channel B.
  	"""
  	if capture_time <= 0:
  		raise ValueError('capture_time must be greater than zero.')
  
  	sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  	sock.connect((IP, port))
  	sock.send('%.2f\r' % capture_time)
  	assert sock.recv(1024) == 'acquiring'
  	time.sleep(capture_time + 1)
  	filename = sock.recv(1024)
  	assert filename[-3:] == 'csv'
  	sock.close()
  	return np.loadtxt('data/signals/' + filename, delimiter=',',
                            dtype=np.dtype('d'), unpack=True)
  
subject: make sure dtype matches what labview sends