Sperry Marine 4914-CA, Operation, Installation And Service Manual

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The system shown in figure 1-13 below is the standard configuration for
a dual NAVIGAT X MK 1 gyrocompass system.
In addition to the two NAVIGAT X MK 1 gyrocompasses, this system
comprises the NAVITWIN IV heading management system (HMS) and
the Switch-Over Unit Type 4932.
By selecting the active heading source at the NAVITWIN IV, the operator
determines which gyrocompasses’ data is distributed via the Switch-
Over Unit to external equipment, such as heading control systems,
RADAR, compass repeaters etc.
The NAVITWIN’s heading diff. alarm function permits to monitor the dif-
ference between any two of the available heading sources. The off head-
ing alarm function permits to monitor the difference between the actual
heading from the active source and the set heading order, as received
from a heading control system or entered manually.
Alarms generated locally by a NAVIGAT gyrocompass are indicated and
may be acknowledged at the NAVITWIN IV. In turn, the NAVITWIN IV
transmits system-wide operational settings and setup parameters to the
NAVIGAT gyrocompasses. The available heading sources, the current
source selection and the heading difference alarm threshold (hdg. diff.
threshold) are also indicated at both gyrocompasses.
If a magnetic compass heading source is installed, the NAVITWIN
applies magnetic variation and distributes the data to external equip-
ment (TMC function). In case of failure of the gyrocompasses, the mag-
netic compass heading source may be activated to provide an
emergency heading reference for repeaters and other peripheral equip-
ment.
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GYRO
1
GYRO
2
MAGN
COMP
246.8
246.7
247.0
G1 Hdg.
G2 Hdg.
M Hdg.
Source Sel.
Status
Alarm Status
(Hdg. Diff, Off Hdg)
G/ M Headings,
RoT, and all other
data/signals
distributed via
Switch-Over Unit
Switch-Over Unit
NAVITWIN IV
G2
M
G1
kçíÉ A system with one NAVIGAT X MK 1 and one NAVIGAT 2100 / NAVIGAT
3000 fiber-optic gyrocompass is also possible in an otherwise identical
configuration.