CONFIGURATION AND CALIBRATION –Software Config.
Page 61 of 80
The NFU Accelerate and NFU Decelerate values provide the same control
over the rudder speed while operating in the Non Follow Up mode of
steering control. The NFU Decelerate value should be quite small in order
to avoid the rudder overshooting the desired position when the NFU input
device is released.
The NFU Output Current value is used to limit the current to the
proportional valve while operating under Non Follow Up steering control.
Since NFU control does not actively monitor and control the rotational
speed of the rudder, limiting the NFU Output Current will limit the
maximum rotational speed of the rudder while using the NFU input device.
The Proportional Slow Speed value will determine the rotational speed of
the rudder when the Fast Rudder Speed mode is toggled off. This value is
a percentage of the fast rudder speed value entered at top of the window.
If the hard over to hard over time entered at the top of the window is 12
seconds and the Proportional Slow Speed value is set to 50% then this
will result in 12 and 24 second hard over to hard over times when the Fast
Rudder Speed mode is toggled on and off respectively.
For systems with on-off valves, the FFU Deadband data entry block
contains the value in degrees for the system sensitivity under FFU control.
This value should be set as low as possible without causing the system to
overshoot or oscillate. The final setting will be dependent on the overall
rudder speed and hydraulic response and should therefore be fine tuned
during calibration.
FFU Fast Speed Angle determines the angular difference between the
FFU commanded angle and the actual rudder angle where the system will
engage the hydraulic power unit’s high speed solenoid.
FFU Slow Speed On Delay controls the number of seconds the system
will wait before sending an initial command to the directional solenoid
valve. This setting is used to ensure that when the rudder movement
changes direction it will pause for a brief moment in the stopped position
before proceeding in the opposite direction. This will reduce hydraulic
hammering and mechanical wear and tear during rudder movements.
FFU Fast Speed On Delay is used to ensure that if a large change in
rudder command is given (i.e. larger than the FFU Fast Speed Angle) the
system will first step through the slow rudder movement for a period of
time before energizing the high speed solenoid. Again, this will help
reduce hammering and wear and tear on the mechanical components.
Doc No.: MAN01504, 20-02-06 DSC 100 & MCP 100 Manual
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