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Connection of robot and computer XMLRPCLIB Error

asked 2019-11-21 04:52:52 -0600

vonunwerth gravatar image

Hi there, i want to connect our robot to a computer to send all messages to him. I set ROS_MASTER_URI as described in the ROS Network Setup and it seems to be correct. If i change something, i get the error "Can not communicate with master". So i think the connection settings are fine. But if i execute rostopic list on the robots computer i get the following error:

  Traceback (most recent call last):
  File "/opt/ros/kinetic/bin/rostopic", line 35, in <module>
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rostopic/", line 2099, in rostopicmain
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rostopic/", line 2039, in _rostopic_cmd_list
    exitval = _rostopic_list(topic, verbose=options.verbose, subscribers_only=options.subscribers, publishers_only=options.publishers, group_by_host=options.hostname) or 0
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rostopic/", line 1205, in _rostopic_list
    state = master.getSystemState()
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rosgraph/", line 481, in getSystemState
    return self._succeed(self.handle.getSystemState(self.caller_id))
  File "/usr/lib/python2.7/", line 1243, in __call__
    return self.__send(self.__name, args)
  File "/usr/lib/python2.7/", line 1602, in __request
  File "/usr/lib/python2.7/", line 1283, in request
    return self.single_request(host, handler, request_body, verbose)
  File "/usr/lib/python2.7/", line 1316, in single_request
    return self.parse_response(response)
  File "/usr/lib/python2.7/", line 1493, in parse_response
    return u.close()
  File "/usr/lib/python2.7/", line 800, in close
    raise Fault(**self._stack[0])
xmlrpclib.Fault: <Fault 1: '<type \'exceptions.Exception\'>:method "getSystemState" is not supported'>

Do you think my approach of sending all messages to a control computer is wrong or do you have any thought about that error? Thanks for your help

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If you are getting "Can not communicate with master" then connection setting are not fine. When you are connected to master you should be able to see all the topic and nodes and their info.

Choco93 gravatar image Choco93  ( 2019-11-21 05:15:31 -0600 )edit

Correct. But this error just happends if i change something (to a wrong ip for example). If the settings are "correct" the XMLRPC Error appears.

vonunwerth gravatar image vonunwerth  ( 2019-11-21 05:47:46 -0600 )edit

So, which values have you configured for ROS_MASTER_URI? And what are the IPs / hostnames of the PCs involved?

gvdhoorn gravatar image gvdhoorn  ( 2019-11-21 09:22:26 -0600 )edit

Did you find the cause of the problem? What was your solution? I have the same error.

Andreas Z gravatar image Andreas Z  ( 2020-11-09 05:10:17 -0600 )edit

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answered 2021-02-19 09:21:22 -0600

vonunwerth gravatar image

If i remeber correctly, the problem was that both machines did work with other ROS versions.

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Asked: 2019-11-21 04:52:52 -0600

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Last updated: Feb 19 '21