Teach pendant error message triggers protective stop

[URJala]

Affected ROS2 Driver version(s)

3.0.2

Used ROS distribution.

Other

Which combination of platform is the ROS driver running on.

Docker

How is the UR ROS2 Driver installed.

Build both the ROS driver and UR Client Library from source

Which robot platform is the driver connected to.

Real robot, UR E-series robot, URSim in docker

Robot SW / URSim version(s)

5.20

How is the ROS driver used.

Through the robot teach pendant using External Control URCap

Issue details

Summary

Sometimes when getting the teach pendant error message mentioned in #1251 , a protective stop is triggered on the robot.

Issue details

Sometimes the error message reported by the external control script is too long for the controller to handle. This triggers a protective stop, as it makes the servo_thread too slow. See the images.

Steps to Reproduce

Trigger the error message as explained in #1251 until the protective stop is triggered. This can take some tries, as it depends on how the numbers in the message are rounded.

Expected Behavior

The error message shouldnt trigger a protective stop.

Actual Behavior

The error message slows down a real time thread and triggers a protective stop.

Relevant log output

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[urfeex]

So, the protective stop happens only, when the string is too long?

[urfeex]

UniversalRobots/Universal_Robots_Client_Library#256 could potentially help in mitigating this.