BECKHOFF KL6904 - Manual (Page 45)

Operation
KL6904 43
4.3 Diagnostics
4.3.1 Diagnostic LEDs
4.3.1.1 Diag 1 (green)
The Diag 1 LED indicates the state of the TwinSAFE interface.
Flashing Code Meaning
LED illuminated continuously normal operation:
TwinSAFE communication OK
rapid flickering, alternating with 1 flash pulse Communication error: at least one connection is
not in Run state.
rapid flickering, alternating with 2 flash pulses Error in the function block
rapid flickering, alternating with 3 flash pulses Error in the function block and
communication error: at least one connection is
not in Run state.
These errors can be rest through a falling edge at the ERR_ACK input of the TwinSAFE group.