Internal Terminal Error (μC2)

What does Diag3:lit, Diag4:off mean?

This LED combination (Diag 3 lit, Diag 4 off) indicates an internal error related to microcontroller 2 (μC2) of the terminal. This is a global fault, leading to the shutdown of the terminal. Similar to μC1 errors, these faults typically require inspection by the manufacturer.

• An internal error or fault has occurred within the second microcontroller (μC2) of the terminal, or μC1 is operational.
• Hardware failure or software issue specifically affecting the secondary processing unit.
• μC1 is functioning, but μC2 has detected an internal anomaly.

Click steps to track your progress.

1. 1

   Record the exact LED states (Diag 3 lit, Diag 4 off) for documentation.

2. 2

   Power cycle the EL6900 terminal and observe if the fault clears or reoccurs immediately upon restart.

3. 3

   Access the TwinCAT System Manager to check for any additional diagnostic messages or system events logged by the EL6900 prior to the shutdown.