Acyclic K-bus Function Active (TwinCAT)

What does State Variable Bit 15 mean?

The K-bus State variable in TwinCAT has Bit 15 set, indicating that an acyclic K-bus function, such as a K-bus reset, is currently active. While not always an error, it signifies that synchronous K-bus operation might be temporarily interrupted.

• An acyclic K-bus function (e.g., parameterization) is active.
• Acyclic communication process is blocking cyclic data transfer.
• Attempt to access acyclic functions while cyclic communication is active.
• Long-running acyclic operation.

Click steps to track your progress.

1. 1

   Confirm if an acyclic K-bus function (e.g., IOF_DeviceReset) was intentionally triggered in the PLC program or TwinCAT System Manager.

2. 2

   Monitor the K-bus status after the acyclic function completes to ensure normal, synchronous operation resumes and Bit 15 clears.