title: DMM , Python and Serial port: During a loop - the communication is suddenly stops
body: <p>I'm using Agilent DMM in order to measure.
  I communicate with it using Python 2.7 and PySerial module.
  The idea: using a FOR loop, I read from the DMM and get data.
  It is working fine until some point, each time a different point.</p>
  
  <p>for example: If I set the loop to measure 20k times, it suddenly stops after 1k times, next try it might stop after 5k times....
  stops - means that the DMM stops send data and python remains in a kind of waiting state. My scripts gets stuck and I have to terminate it. There is no error and I have no idea why.
  I tried adding timeouts (Sleep) between measurements and it sis not solve the problem.
  Here are the main commands in my scripts:</p>
  
  <pre><code># configure the serial connections 
  ser = serial.Serial(
      port='com3',
      baudrate=19200,
      parity=serial.PARITY_NONE,
      stopbits=serial.STOPBITS_ONE,
      bytesize=serial.EIGHTBITS
  }
  
  
  ser.write("CONF:CURRent:DC" + '\r\n')
  time.sleep(1)
  ser.write("SENS:CURR:DC:RANGe:UPP 0.05" + '\r\n')
  time.sleep(1.5)
  
  for m in range (0, 2000):
  try:
      ser.write('READ?' + '\r\n')
      out += ser.read(18)
      print "out = ",out
  except:
      print "error!"
  </code></pre>
  
  <p>The loop is running, sometimes it "survive" till the end but most of the times it just stops, please advice. Please note that I never get into the "except" part. adding "try" was not helping...</p>
  
  <p>Thank you!</p>
  
  <p>~ Dolphin ~</p>