Diagnostic LEDs for Ethernet

After switching on, the Fieldbus Box  immediately checks the connected configuration. Error-free start-up is indicated when the red I/O ERR LED goes out. If the I/O ERR LED blinks, an error in the area of the Inputs/Outputs is indicated. The error code can be determined from the frequency and number of blinks. This permits rapid rectification of the error.

The module has two groups of LEDs for the display of status.
The upper group with four LEDs indicates the status of the respective fieldbus. The significance of the fieldbus status LEDs is explained in the appropriate sections of this manual. It corresponds to the usual fieldbus display.

At the lower end of the Module are two more green LEDs that indicate the supply voltage. The left hand LED indicates the presence of the 24 VDC supply for the Fieldbus Box. The right hand LED indicates the presence of the supply to the power contacts.

Diagnostic LEDs for Ethernet 1:

LEDs for power supply diagnosis





Physical connection present

No physical connection present


Flashing: Bus traffic present

No bus traffic (bus idle)


The LED flashes slowly if DHCP or BootP is active but the Bus Coupler has not yet received an IP address
The LED flashes rapidly (5 times, only when switching on); the Bus Coupler is addressed with ARP. The settings on the rotary switches are not valid.

No error.


ON, when the box receives more than one Ethernet frame per module cycle. The master sends to fast!



Out - Watchdog error or no communication

- Start communication
- reset WD error

On - Watchdog works

No error


Diagnostic LEDs for Ethernet 2:

LEDs for power supply diagnosis



Left LED off

Module has no power

Left LED red

Short circuit detection for sensor supply (< 500mA) is active. Sensors/Inputs are not supplied anymore

Right LED off

No 24 VDC power for the outputs connected