BECKHOFF BK3xx0 - Manual (Page 28)

Notes on the Documentation
26 Fieldbus Components
4. Parameterisation and Commissioning
Start-up Behaviour of the Bus Coupler
Immediately after being switched on, the Bus Coupler checks, in the course of a self test, all the functions of its
components and the communication on the K-Bus. The red I/O LED blinks while this is happening After completion of
the self-test, the Bus Coupler starts to test the attached Bus Terminals (the Bus Terminal Test), and reads in the
configuration. The Bus Terminal configuration is used to generate an internal structure list, which is not accessible
from outside. In case of an error, the Bus Coupler enters the STOP state. Once the start-up has completed without
error, the Bus Coupler enters the fieldbus start state.
The Bus Coupler can be made to enter the normal operating state by switching it on again once the fault has been
rectified.