2016/12/04 03:02:41 -     raise LockedError(status, device)
2016/12/04 03:02:41 - LockedError: (1, '/dev/ttyUSB4')
2016/12/04 03:02:56 -     raise LockedError(status, device)
2016/12/04 03:02:56 - LockedError: (1, '/dev/ttyUSB4')
2016/12/04 03:02:59 - Exception in thread Thread-20:
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 810, in __bootstrap_inner
    self.run()
  File "/usr/lib/python2.7/threading.py", line 763, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/usr/local/lib/python2.7/dist-packages/uhdas/serial/tk_terminal.py", line 415, in listen
    self.outfile.write(cc)
ValueError: I/O operation on closed file