ABB Ability 800xA Series User Manual page 49

2 Hardware Installation
2.9 Replacing a LD 800 HSE Ex by a New LD 810HSE Ex
7. Connect the Ethernet cable and the redundancy link wiring.
Make sure that the redundancy link wiring is connected before plugging in the power
terminal block.
If the new LD 810HSE Ex is powered while the redundancy link is missing, it will
behave like an independent, non-redundant primary device. If in this case the Linking
Device has a valid (possibly unknown) configuration, it might use H1 node addresses
that are already in use on the H1 links. This will disturb or interrupt communication
and application processing on the H1 links.
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