3.1 Item definition. The turret control unit, Drawing 11830908, shall be
configured for use in an AH-IS helicopter equipped with the XM97E1 20mm
Armament Subsystem. This control is a totally enclosed box which contains the
required circuitry to translate signals from the aircraft turret electrical
system into appropriate signals for turret drive motor control. The following
functions shall be performed by the turret control unit (TCU)
a. Convert resolver type signals into appropriate split field series
wound d-c drive motor excitation.
b. Provide a d-c analog signal indicating the amplitude of the input
position command signal (linear up to 750mV rms on the input).
c. Provide an electrical interface to control emergency stow
d. Provide mode selection as to which position comnand signal
controls the turrent drive motor.
e. Provide boresight adjustment capability in the fixed forward mode.
f. Provide a logic signal indicating gunner stow position is
g. Provide an action signal interlock when fixed forward signal is
h. Provide slow slew rates for azimuth and elevation turret
i. Provide for the constant gain transfer function in the azimuth
servo loop as a function of the Cos El signal.
Provide filtered zener power for the limit switch assemblies.
3.1.1 Major component list. The major component list shall be as
specified in Table I.