Detailed Block Diagram

Custom Search

Overall Block Diagram - Functional Operation

TM-55-1905-220-14-9 Landing Craft Utility LCU 1671-1679 NSN 1905-01-009-1056 Manual

Receiver Power Panel

TM 55-1905-220-14-9

4-66.1. TANK LEVEL INDICATION - RECEIVER - MAINTENANCE INSTRUCTIONS.

General.

Receivers convert the electrical signals generated by the fluid level detection devices (transmitters) to

deflections on meters calibrated in gallons.

Detailed Block Diagram.

(1)

Receiver Module.

(a)

The circuits stages that perform the level indication when using a receiver module are shown

below. The +17-volt dc level generated by the power distribution circuits is applied to CALIBRATE

potentiometer R5 located in the level indication circuit on the receiver module. The connection of CALIBRATE

potentiometer R5 is such that it forms a voltage divider with serially connected transmitters located in the tank.

The setting of CALIBRATE potentiometer R5 is adjusted to cause a selected portion of the +17-volt dc level to

be applied as a calibrated voltage level across the transmitters. The amplitude of the calibrated voltage level is

that which produces maximum deflection of fluid level meter M1 on the receiver module when the fluid level is

at its maximum.

(b)

A float on the transmitter causes a portion of the calibrated voltage that is proportional to the

height of the float is fed Ago to ON-OFF-FULL REF. switch contacts S1-C. During operation, ON-OFF-FULL

REF. switch S1 is in the ON position and the level signal is applied to slosh dampening network R1-R2-C1.

Slosh dampening network R1-R2-C1 integrates any changes in the level signal amplitude and thereby

compensates for variations caused by the sloshing of fluid in the tank. The slosh-dampened meter signal at the

output of the net-work is fed to the plus terminal of fluid level meter M1. The minus terminal of meter M1 is

connected directly on the 17-volt return via a jumper connection.

(c)

Fluid level meter M1 on the receiver module is deflected by an amount determined by the

amplitude of the signal. In On-OFF-FULL REF. switch S1 is placed in the FULL REF. positin, the full calibrated

voltage output of CALIBRATE potentiometer R5 is connected through resistor R3, when simulates the

resistance of resistor in the transmitter, to the slosh dampening network in place of the fluid level signal. With

the full calibrated voltage applied to the meter, CALIBRATE potentiometer R5 is set at the position that

corresponds to maximum meter deflection.

4-1396