Unable to negotiate protocol version

Technical Questions Robot Communication
1

Hi,
RTDE with ur3. Basically it’s working. But sometimes I get “Unable to negotiate protocol version” error, my program terminates.

More info:
Python, LAN network, software version 3.4.5.100(Oct 02 2017)

Any ideas?
Please!
Thanks

2

Hi,

maybe a bit more information regarding the setup could help finding the cause of this behavior.

Can you upload an example where the error can be reproduced?
Is there any pattern behind this or can be reproduced consistently?
Does it happen only on the robot or can it be observed on the offline simulator as well?

Thank you!

3 
thank you for your quick response

urmover and urcon are the 2 classes that use ur robot
class urbot help to manage so that only one object can used the robot at anytime
class urcon is omitted for only urmover is used most of the times

The codes are not executable. Just for the logic for it is not easy to cut a small piece of code that can run and reproduce exactly the same situation when the problem occurred
It cannot be surely reproduced, 
It can be good for a whole day. 
It seems that it may occur if there are many bug caused (from other parts of codes) terminations. In some cases, I have to restart the robot to may it works.

Is the robot has any information logged when this occurs

thanks

4

I have the same problem (Unable to negotiate protocol version), sometimes “lost connection with controller”. This is the setup:

  • I’m using UR Software 5.11.0.108249
  • RTDE example is adapted to get e.g. speed slider value
  • the daemon creates a python thread which is a RTDE wrapper. Wrapper periodically tries to:
    • establish connection with RTDE connect()
    • negotiate protocol version
    • get controller version
    • setup recipe (rtde.send_output_setup)
    • start sync (rtde.send_start)
    • receive
      If any call fails, then re-connection is performed (disconnection and then the same sequence from above, again).
      I even use lazy initialization (delayed startup) of this wrapper because controller resources, but sometimes needs more than 1 minute (after startup) to have all positive in a sequence above.

I do not have the problem when I’m using offline simulator.
Any feedback appreciated.