Diag3:off, Diag4:2_pulses

Communication Error

Beckhoff · EL6900 Operating Instructions

What does Diag3:off, Diag4:2_pulses mean?

This diagnostic flashing code (Diag 3 off, Diag 4: 2 flash pulses with longer pause) indicates a communication error within one of the TwinSAFE groups. This suggests issues with data exchange between safety devices on the EtherCAT network, potentially due to faulty wiring, incorrect addressing, or timing discrepancies.

Additional Steps

Steps 1–2 are listed in Priority Fix.

  1. 3

    Check the EtherCAT network topology and addressing configuration in TwinCAT to ensure it precisely matches the safety project setup.

Source: Beckhoff EL6900 Operating Instructions
Open Manual (Page 54)