On A320 there are 3 ADIRS. ADIRS 1 is shown on Capt display, ADIRS 2 on F/O display. They can be selected manually. The AoA value is not displayed by default, but there is an option for it. However the values are always used by computers.
Each ADIRS contains an air data reference (ADR) and an inertial reference (IR). Each ADR each is connected to a separate AoA probe.
If values disagree, pilot intervention is required. From this report:
If one ADR has been detected as being faulty, or has been rejected by the flight control computers, and there is an airspeed or angle of attack disagreement between the remaining two ADRs, then a level 2 alert is raised. This activates the master caution and presents an amber NAV ADR DISAGREE message on the ECAM.
All pictures are from the report.