Universal Robots Forum

Exception Caught in Thread Timer-20


Introduction to the issue
Robot is already installed at customer, but not yet used in production, so what exactly happened before is hard to estimate. After starting a cycle (externally from PLC) one of the robots did not move and the below shown message was visible on the teach pendant “Exception Caught in Thread Timer -20”.


  • Affected Robot Software Version(s):
  • Affected Robot Hardware Version(s): eSeries
  • Robot Serial Number: 20205001402
  • UR+ product(s) installed: none
  • URCaps Software version(s): none


  • not possible to play program

Issue details

This part is important in order to clarify the severity of the issue.

Use Case and Setup

  • Robot is used for screw driving application.

Project status at point of discovered

  • Before I started.

Steps to Reproduce

  • not able to reproduce the situation

Workaround Suggestion

  • Robot had to be restarted.