SYSTEM OPERATION – Steering Modes
Page 49 of 80
Once the AUTOPILOT button is pressed the autopilot transfer process is
started and the autopilot request signal is sent out. If the DSC does not
receive the autopilot acknowledge signal from the autopilot system within
10 seconds, the audio indicator will begin to beep. If the autopilot
acknowledge signal is not received within 20 seconds the audio indicator
will change to a steady signal. The operator can cancel the autopilot
request and stop the audio signal at any time by re-selecting another
mode of steering control. If, while the system is operating in autopilot
mode, the autopilot acknowledge signals is lost, the directional solenoid
outputs will be turned off and the AUTOPILOT indicator will begin to flash.
A NFU input device connected to an MCP can be configured through the
DSC setup program to provide a “dodge” function while the system is
operating under autopilot control. Under autopilot control, operation of the
NFU input device will momentarily move the rudder from the position
commanded by the autopilot system. Once the NFU device is released
control of the rudder position will be returned to the autopilot.
Autopilot rudder command signals are interfaced to the steering control
system through either directional solenoid command signals or through
analog rudder order signals. Directional solenoid command signals are
similar to NFU type input signals in that the steering system will move the
rudder in the port or starboard direction as long as the autopilot port or
starboard command is present. When the autopilot command is released
the rudder movement is stopped. This type of interface requires that the
autopilot system has its own rudder feedback signal. Directional solenoid
command signals can not take full advantage of a proportional rudder
control system although a limited amount of acceleration and deceleration
can be applied without confusing the autopilot system.
Analog rudder order signals are similar to FFU type input signals in that
the steering system receives an analog signal representing a desired
rudder position. The steering control system then takes care of moving
the rudder to the desired position. This type of autopilot interface normally
does not require that the autopilot system have its own rudder feedback
signal. Analog rudder command signals allow a proportional rudder
control system to accelerate and decelerate the steering gear throughout
its movements.
3.4 RUDDER SPEED
The RUDDER SPEED button and indicator are used to toggle the system
between slow and fast rudder speeds. Selection of rudder speed will
affect steering control systems differently depending on which type of
Doc No.: MAN01504, 20-02-06 DSC 100 & MCP 100 Manual
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