K-bus Watchdog Error (TwinCAT)

What does State Variable Bit 11 mean?

The K-bus State variable in TwinCAT has Bit 11 set, indicating a K-bus watchdog error. This typically means the K-bus communication or processing has stopped responding within the configured watchdog timeframe, suggesting a communication loss or system hang.

• K-bus communication watchdog timed out.
• Loss of communication with one or more K-bus devices.
• Intermittent communication failures on the K-bus.
• Failure of a bus terminal to acknowledge data periodically.

Click steps to track your progress.

1. 1

   Verify the overall K-bus communication integrity. Check for any physical breaks in the bus, defective terminals, or power supply issues (refer to page 80 for K-bus ERR LED diagnostics).

2. 2

   Review the TwinCAT task configuration for the K-bus, ensuring the watchdog settings (e.g., cycle time, timeout) are appropriate for the application and system responsiveness.