NORTHROP GRUMMAN naviguide 4000, User, Installation And Service Manual

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056336 Rev. AA NAVIGUIDE 4000
Page 1–2 1.2: System Components
1.2 System Components
1.2.1 Steering Control Unit
The Steering Control Unit (SCU) contains an FU
control amplifier and all of the system’s in- and
output interfaces.
Each SCU may be equipped with up to two
daughterboards providing the required inter-
faces to the vessel’s steering gear.
The available daughterboards include inter-
faces to conventional AC or DC solenoid valves
(bang-bang), proportional solenoid valves, and
an analogue I/O board offering two isolated out-
puts (rudder order or error signals, ±10 V).
Two Steering Control Interface Units may be combined to provide dual FU control
for a single rudder steering gear or single FU control for a dual rudder steering
gear. Four Interface Units may be combined to provide dual FU control for dual
rudder steering gears.
1.2.2 Steering Mode Selector / NFU Tiller
The Steering Mode Selector / NFU Tiller is
located at the main steering position and se-
lects between NFU and secondary (bus)
steering modes. In NFU steering mode, the
integrated NFU tiller actuates the solenoid
valves directly.
In bus steering mode, a Steering Mode Se-
lector Bus Interface Unit (see 1.2.6.3) is used to select between the steering
modes available under bus control (e.g. “FU”, “Auto”, “External” etc.).
If so configured, the NFU tiller may be used to override the bus steering mode by
moving the tiller from the midship’s detent. The override capability may be enabled
for all bus steering modes or for specific modes only.
1.2.3 Mechanical Mode Switch
Instead of the Steering Mode Selector / NFU
tiller and Steering Mode Selector Bus Inter-
face Unit, a conventional mechanical mode
switch may be installed at the main steering
position.
A mechanical mode switch selects directly
between the available steering modes, in-
cluding NFU. A separate NFU tiller is used to actuate the solenoid valves in NFU
steering mode.