WAGO 750 Series Manual page 118

114 • Fieldbus Controller 750-841
LED Display
Fault code 4: "Internal bus physical fault"
Fault argument Fault description
- Error in internal bus data
communication or interruption of
the internal bus at the coupler
n* Interruption of the internal bus
th
after the n
Trouble shooting
Turn off the power supply of the
node. Place an I/O module with
process data behind the coupler
and note the error argument after
the power supply is turned on. If
no error argument is given by the
I/O LED, replace the coupler.
Otherwise detect faulty I/O
module as follows: turn off the
power supply. Place the end
module in the middle of the
fieldbus node. Turn the power
supply on again.
– If the LED is still blinking, turn
off the power supply and place the
end module in the middle of the
first half of the node (towards the
coupler).
– If the LED doesn't blink, turn off
the power supply and place the end
module in the middle of the second
half of the node (away from the
coupler).
Turn the power supply on again.
Repeat this procedure until the
faulty I/O module is detected.
Replace the faulty I/O module.
If there is only one I/O module left
but the LED is still blinking, then
this I/O module or the coupler is
defective. Replace defective
component.
Turn off the power supply of the
process data module. node, exchange the (n+1)
data module and turn the power
supply on again.
th
process
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