Automatic control for a limiting device using duplicated control circuits

摘要

A system for generating electrical signals which are intended to control a flow limiting device 13, in particular in a fuel control apparatus 10, 12, has duplicated signal generating circuits 18, 31,which are responsive to operation of the fuel control apparatus 10, 12 and which generate nominally identical output signals when an operating condition NL or NI of the fuel control apparatus 10, 12 exceeds predetermined limits. Output signals from the duplicated circuits 18, 31 are supplied to the limiting device 13 by way of respective control circuits 20, 33 each of which is enabled by the presence of a corresponding output signal from the other of the signal generating circuits 18, 31. Means are provided for detecting a malfunction of one of the signal generating circuits 18 or 31 and for permanently enabling the control circuit 33 or 20 through which output signals from the other of the signal generating circuits 31 or 18 is supplied. IMAGE