Universal Robots Forum

Unable to negotiate protocol version

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 02 2017)

Any ideas?


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!

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