ABB AC500 V3 Hardware Manual page 322

Device specifications
I/O modules > Digital I/O modules
1 I/O bus
2 4.0 - 4.7: Connected with UP (switch) -> Input;
Connected with ZP (load) -> Output
3 Switchgear cabinet earth
The module provides several diagnosis functions .
322
CAUTION!
The process supply voltage must be included in the grounding concept (e. g.
grounding of the negative pole).
3ADR010278, 3, en_US 2022/01/31