Introduction
Page 7 of 31
Doc No.: MAN01502, 27-02-01 SCA 300 Manual
the rudder order and rudder angle signals are the same at which time the
SCA turns off the directional solenoid valve. The rudder is now at the
desired full follow-up angle. By adjusting the SCA 300 the following
performance parameters can be altered:
Internal Angle Limit - allows for electronic adjustment of the maximum full
follow-up rudder angle. This leaves the limit switches in Jastram's RFU
1300 as back up when the SCA is operating under full follow-up steering.
(See Figure 2)
Deadband - provides a region about a rudder and helm set position for
which a small change in position of the helm will not cause movement at
the rudder. The size of the helms "dead" region is adjustable.
Gain - sets the rate of acceleration and deceleration of the rudder. The
most visible effect of this adjustment is that it changes the angular
difference between rudder order and rudder angle, at which the rudder
begins to decelerate.
Full Follow-up Speed - adjusts the hard over to hard over time of the
steering gear in full follow-up mode.
Non Follow-up Speed - adjusts the hard over to hard over time of the
steering gear in non follow-up mode.
SCA 300 Output Devices
The SCA 300 can output to rudder angle indicators (RAI) as well as rudder
order indicators (ROI).
The SCA contains two rudder angle indicator outputs, CRAI (constant
rudder angle indication) and RAI. The CRAI signal is the rudder angle
indicator signal output from the RFU 1300 rudder feedback unit operating
in “stand alone” mode. This signal is simply routed through the SCA. The
RAI signal is the rudder angle indicator signal output from the SCA. This
RAI signal is used when a rudder feedback unit other than the RFU 1300
is used with the SCA.
The SCA also outputs a rudder order indicator signal. The rudder order
indicator gives the present position of the full follow-up steering input
device and therefore the full follow-up rudder command at the SCA.
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