ECU vs EEC and Automated Power and prop management
The. ECU (Engine control Unit) ceased since the advent of the 500 series and replaced by EEC..Electronic Engine Control...more automated in supervision and electronic engine control where the PLs were operated on scheduled gated notches..similar to A320 family and the PMS..Power Management selector in conjuction with EEC and ATPCS manages the engine power in its various flight phases and the CLs in Auto mode manages RPM.Fuel is metered automatically according to some engine control laws.So much automation could lead to pilots getting confused..as to what is it doing now?? Before control intervention..Where as conventional power controls..pilots react instinctively by adding or removing power more directly.
On this type of power Management the Pls are (for normal ops) in the notch and PMS regulates optimum power for the EEC computed ambient conditions.If more power is required for emergency contingencies the PL can be pushed futher up to the ramp..and if still in dire need for extra power..the PL can be advanced to "the wall" (no firewall as such in this type..).
To add complexity to the power management system there are the Multi Function Computers that supervise and authorise certain operation. The ATR is not your conventional steam gauge turboprop as those who have flown it will tell.