If call to GetPLCstatus can't be executed in PLC, then obtained status is disconnected. Status on "None" is not relevant anymore, and is replaced by Disconnected.
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# See COPYING.Runtime file for copyrights details.
LogLevels = ["CRITICAL", "WARNING", "INFO", "DEBUG"]
LogLevelsCount = len(LogLevels)
LogLevelsDict = dict(zip(LogLevels, range(LogLevelsCount)))
LogLevelsDefault = LogLevelsDict["DEBUG"]