KRC0620

Common Causes

• KRL program or WorkVisual configuration attempted to change baud rate, parity, or stop bits on an open serial or SINEC L2 channel
• Channel was not properly closed before attempting to reassign it to a different device or modify its communication settings
• Multiple KRL tasks are simultaneously attempting to access and reconfigure the same communication channel with conflicting parameters
• WorkVisual channel configuration was modified and downloaded while the KRC4 controller has an active connection on that channel
• SafeOperation or process automation script interfered with normal channel state management during a parameter update sequence

Troubleshooting Steps

1. 1Review the KRL source code and identify where the channel parameter change was attempted, checking for missing close commands before reassignment
2. 2Use KUKA smartPAD to navigate to the channel configuration and verify current channel state is Idle or Closed before attempting modifications
3. 3Ensure all KRL tasks accessing the communication channel are properly synchronized and that only one task manages channel open and close operations
4. 4In WorkVisual, close the affected channel in the Network configuration, save and download the project to the KRC4 controller
5. 5Power cycle the KRC4 controller to reset all communication channel states to their default closed configuration
6. 6Modify the KRL program to explicitly close the channel using the appropriate CIO or communication instruction before changing any parameters, then re-download and test