Start with the I/O module’s BU-type requirement
Type A0 identifies the BaseUnit interface and terminal assignment. Check the exact I/O module manual for the permitted type and pin assignment. A BaseUnit supplies the connection platform; its physical terminal count is not a count of independent I/O channels.
Check where the load supply enters the station
The light-coloured and dark-coloured arrangements in the BaseUnits manual distinguish a new potential group from a continued group. Trace P1, P2 and AUX as well as the process and infeed terminals. The I/O-module wiring diagram determines which terminal carries each signal or supply.
Separate process-terminal and group-current limits
For this A0 arrangement, the manual specifies a maximum of 2 A per process terminal and a maximum of 10 A for the potential-group supply. Include the modules and their connected loads in the group total; the 10 A bus limit does not allow 10 A through each I/O terminal.
The ten AUX terminals provide access to the AUX bus for the specified potential or protective-conductor arrangement. They are not ten extra digital inputs. Check the AUX potential and grouping in the wiring plan.