Diagnostic LEDs

Coupler Terminal (KL9050)

Diagnostic LEDs for power supply

LED	Function	Display	Meaning
Power V_k (green)	Indicates whether the supply voltage for the electronics of the Coupler Terminal is switched on.	on	Supply voltage present
Power V_k (green)		off	Power supply has failed or is switched off
Power (green)	Indicates whether the supply voltage for the I/O terminals of the terminal block is switched on. The power supply of the terminals is via the power contacts.	on	Supply voltage present
Power (green)		off	Power supply has failed or is switched off

Diagnostic LEDs on the RJ45 socket for the incoming K-Bus extension (K-Bus IN)

LED RUN (green)	LED ERR (red)	Meaning	Possible causes
on	off	Data transmission on the K-bus extension is active	Supply voltage present Connection established properly
off	on	Data transmission on the K-bus extension is interrupted	Ethernet cable not connected Wire breakage or short-circuit in the Ethernet cable RJ45 plug has been pulled out Function Switch of a KL9050 not set correctly
off	off	Data transmission on the K-bus extension is interrupted	Supply voltage for the electronics in the coupler terminal has failed Coupler terminal defective

End Terminal with RJ45 socket (KL9020)

The End Terminal KL9020 has no separate diagnostic LEDs. For diagnosing the K-bus of your bus terminal block, the diagnostic LEDs I/O RUN and I/O ERR of the Fieldbus Coupler installed there are used.

Typical diagnostic LEDs of a Fieldbus Coupler

LED I/O RUN (green)	LED I/O ERR (red)	Meaning	Possible causes
on	off	Data transmission on the K-bus is active	Supply voltage present Connection established properly
off	flashes	Data transmission on the K-bus is interrupted	Bus Terminal not plugged in properly Configuration error A mounted Bus Terminal is defective
off	off	Data transmission on the K-bus is interrupted	Supply voltage for the electronics in the Fieldbus Coupler has failed Fieldbus Coupler defective

Behavior in case of an error

If the communication between two or several bus terminal blocks of a K-bus extension system is interrupted

the green RUN LEDs go out on the RJ45 sockets for the incoming K-bus extension (K-bus IN) on all KL9050s,
the red ERR LEDs light up on the RJ45 sockets for the incoming K-bus extension (K-bus IN) on all KL9050s,
the green LED I/O RUN of your Fieldbus Coupler will go out;
the red LED I/O ERR of the higher-level Fieldbus Coupler will flash rapidly, indicating an interruption of the communication.

Flashing Code

If you now perform a reset for the Fieldbus Coupler, the Fieldbus Coupler searches for the cause of the fault and indicates it as a flashing code via the LED I/O ERR.

A flashing code is made up as follows:

rapid flicker
short break
LED flashes m times for error code m
short break
LED flashes n times for error argument n
short break

Count the error code and the error argument. The flashing code is repeated continuously.

The error code for a K-bus interruption is 4. The error argument indicates the Bus Terminal after which communication was interrupted. Examples are shown in the Fault table for K-bus interruption.