code: def getSystemVariable(self, remote, name):
          
          var = None
          if self.remotes[remote]['username'] and self.remotes[remote]['password']:
              LOG.debug(
                  "ServerThread.getSystemVariable: Getting System variable via JSON-RPC")
              session = self.jsonRpcLogin(remote)
              if not session:
                  return
              try:
                  params = {"_session_id_": session, "name": name}
                  response = self._rpcfunctions.jsonRpcPost(
                      self.remotes[remote]['ip'], self.remotes[remote].get('jsonport', DEFAULT_JSONPORT), "SysVar.getValueByName", params)
                  if response['error'] is None and response['result']:
                      try:
                          var = float(response['result'])
                      except Exception as err:
                          var = response['result'] == 'true'
  
                  self.jsonRpcLogout(remote, session)
              except Exception as err:
                  self.jsonRpcLogout(remote, session)
                  LOG.warning(
                      "ServerThread.getSystemVariable: Exception: %s" % str(err))
          else:
              try:
                  var = self.proxies[
                      "%s-%s" % (self._interface_id, remote)].getSystemVariable(name)
              except Exception as err:
                  LOG.debug(
                      "ServerThread.getSystemVariable: Exception: %s" % str(err))
          return var
docs: Get single system variable from CCU / Homegear