Securing Procedures

supply circuit card fails, a hard-wired BITE fail signal

control monitor sends a battery status signal to the

control indicator, setting the BATTERY STAT indicator.

is sent to the control monitor, which was discussed in

If an overvoltage condition occurs in the battery charger,

the preceding paragraph. The gyro spin supply circuit

5-volt regulator, 13-volt regulator, or DC/DC module,

card is also tested under control of the processor. The

the fault indicator on the faulty card will set, and the con-

remaining circuit cards and assemblies are tested by the

trol monitor will send a signal to the control indicator,

processor. If the processor detects a fault, a signal is sent,

energizing the FAULT PS indicator. The control moni-

causing the four indicators located on the front of the

tor will also turn off the 5-volt regulator, 13-volt regula-

IMU to set in the proper combination to indicate the

tor, and DC/DC module when an overvoltage condition

faulty card. The control indicator also receives a signal,

occurs. The fault indicators will remain set after the

setting the FAULT IMU indicator.

power supply is turned off. A gyro overtemperature

condition, failure of the servoamplifier or gyro spin

ALARM RELAYS.-- A circuit card in the control

supply will also initiate no-go commands to the control

power supply contains alarm summary logic for the

monitor, which will shut down the power supply.

BITE circuits. The alarm summary logic receives

The control monitor also senses the voltage and

hard-wired BITE fault signals, alarm signals from faults

frequency of the 3-phase, 115-volt ac power and

detected by the processor, and alarm signals from the

synchro reference inputs at the transformer rectifier. If

transformer rectifier via the control monitor. Any one

the 3-phase input is lost or exceeds tolerances, the

or all of these signals will cause the alarm summary

control monitor will switch the gyro to battery operation

logic to send a signal to the control indicator, lighting

and send a signal to the control indicator, causing the

the ALARM indicator, and an alarm relay on signal to

BATTERY OPR indicator to come on. If the

the normally energized alarm relay. The alarm relay on

single-phase input is lost or exceeds tolerances, the

signal causes the alarm relay to reenergize, completing

control monitor will disconnect the ship's faultly input,

the circuit for the malfunction summary alarm.

switch on the inverter, sending a signal to the control

indicator, causing the ALARM indicator to set.

When the 3-phase power input is lost or exceeds

tolerances, the control monitor switches the operation to

Circuit cards and assemblies in the synchro signal

amplifier we monitored by hard-wired BITE. The 1X

battery power and sends out an alarm signal to the circuit

heading amplifier, 36X heading amplifier, roll amplifier,

card containing the alarm summary logic. The alarm sum-

pitch amplifier, and inverter in the synchro signal

mary logic sends a signal to the on-battery relay, which

amplifier have fault indicators located on the individual

is normally de-energized. When this relay energizes, it

circuit cards. The fault indicator on the inverter sets

completes the circuit for the on-battery alarm.

when the inverter or inverter magnetics module fails. A

fault in any of these circuit cards or module will cause

SECURING PROCEDURES

the fault indicator on the respective faulty circuit card

to set and a BITE fail signal to be sent to the fault

summary logic located in the inverter. The inverter then

To secure the AN/WSN-2 compass under normal

sends out a signal causing the FAULT BFR indicator on

conditions, refer to figure 4-44 and perform the

the control-indicator to set.

following steps:

If either of the heading amplifiers fail, the inverter

1. Set the MODE control to the POWER OFF

will send a heading fail signal to light the HDG FAIL

position.

indicator on the control-indicator. If the inverter or in-

2. Place the SYN REF switch to the OFF position.

verter magnetics module fail during inverter operation,

the inverter sends a signal to the control monitor to

3. Place the PWR switch to the OFF position.

command a power shutdown. A failure of either the

To secure the compass under emergency conditions,

servoamplifier or gyro spin supply, located in the IMU,

refer to figure 4-44 and perform the following steps:

causes a no-go signal to be sent to the control monitor.

The control monitor initiates a power shutdown and the

1. Place the PWR switch to the OFF position.

IMU fault indicator on the control indicator to set.

2. Place the SYN REF switch to the OFF position.

Circuit cards and assemblies in the IMU are tested

3. Set the MODE control to the POWER OFF

by a combination of hard-wired and software-monitored

BITE. When either the servoamplitier or gyro spin

position.

4-57