Hi
There seems to be a common confusion. The FADEC is not a physical unit. FADEC is the name of the system which includes many components. The FADEC system provides (CFM56-5 engine):
-control the engine fuel and geometry
-optimize engine clearances
-automatic and manual starting
-engine power management
-control of reverser
-Airframe-engine integration
-Built-in-test
-Fault tolerance
-Maintenance data
The most important unit (the brain of the system) is the ECU - Electronic Control Unit. In CFM56-5 engines it controls the engine variables:
-Fuel metering valve
-Variable Stator Vanes
-Variable bleed valves
-Rotor active clearance
-Low pressure turbine clearance
-High pressure turbine clearance
-Thrust reverser
-Starter air valve
-Burner staging valve
-Ignition
-Fuel Return Valve
On the flight deck, the ECAM engine warning display information N1,EGT,N2,FF and warning messages are provided by the ECU which processes the information from several sensors.
Regards