Display Function

RNG data to the display assembly A2A1A3 to display on the LD/R eyepiece

display.

e. Display Function (figure FO-22 of appendix B).

This function

monitors all display data and produces the appropriate information on the

displays and indicators in the LD/R eyepiece display.

The display

function provides visual display of the following data:

The microprocessor U9 of the control logic card A1A2 sends the data for

the AZ, EL, and RNG displays to the display assembly A2A1A3. The binary

coded decimal (BCD)-to-seven-segment decoder U4 decodes the data. The

1-of-12 multiplexer U1 selects which display receives the information.

The LASER FAIL (red) light indicates either a low laser energy condition

(full on) or an overtemperature condition (blinking). If both conditions

exist, the light stays full on. The microprocessor sends the appropriate

signal to the display assembly to light the LASER FAIL indicator.

The BATTERY FAIL (amber) light indicates the battery output has

diminished to an unacceptable level. The battery low comparator U1 in

the power supply card A1A1 monitors the +24 V FILTERED signal. If the

signal drops below +18.0 0.5 V, the battery low comparator routes the

signal BATTERY LOW to the display assembly to turn on the BATTERY FAIL

light.

The FIRE COMMAND (green) light receives its power from external commands.

Either the DMD or FIST sends the appropriate signal, either DMD FIRE CMD

or FIST FIRE CMD, to light the FIRE COMMAND indicator.

The DISPLAY BRIGHT switch A1W1R2 allows you to test the display function

indicators. By placing the DISPLAY BRIGHT switch to the TEST (detent)

position, the DISPLAY TEST signal goes to the microprocessor and to the

FIRE CMD line via CR5 in the control logic card.

The FIRE COMMAND

indicator lights directly.

The microprocessor generates the signals

necessary to test the other displays. When not in the detent position,

the DISPLAY BRIGHT switch controls the brightness of the display. The

RETICLE BRIGHT potentiometer A1W2R1 controls the brightness of reticle

assembly A2A1A1.

25

OD1721