DEPTH CONTROL SYSTEM 



The depth control system consists of four instruments: an in-body, watertight 

 housing containing a depth-keeping servo; a shipboard control unit; a regulated 

 direct current (dc) power supply, Kepco Model JQE 55-2 (M) VP; and a voltage func- 

 tion generator, Hewlett Packard Model 3310A. Diagrams of the circuitry and cabling 

 are contained in Appendix D, DTNSRDC Drawing C-588-1 and 2. 



The in-body instrument housing contains a servo-motor which actuates the hori- 

 zontal tail flap to vary the depth of the depressor. The servo motor is powered 

 from an amplifier where the input comprises the sum of three signals including: 

 depth (from a pressure gage mounted in the bulkhead of the instrument housing) , flap 

 angle (from a potentiometer geared to the servo-motor shaft), and ordered depth 

 which is remotely adjusted aboard ship and wired to the instrument housing by one 

 lead within the towcable. The instrument housing also contains circuitry to allow 

 for a remotely controlled electrical calibration of these sensors. A leak director 

 in the housing will sense any water leaks. If there is a water leak, a series of 

 positive voltage blips will appear on the graphic recording of the depth signal. The 

 underwater housing also included three series voltage regulators; one negative 12 V, 

 one positive 12 V, and one high current positive 12 V regulator for the servo-motor 

 and power amplifier. 



The shipboard control unit, shown in Figure 8, contains operational amplifiers 

 and circuitry for signal conditioning of the depth and flap angle, a summing network 

 to control depressor depth from the RANGE SWITCH, the RANGE VERNIER potentiometer, 

 and the external oscillator. One operational amplifier is used to control the volt- 

 age output of the external power supply so that the output voltage will increase 

 by 30 V when the servo-motor is actually running. When the servo-motor is running, 

 the required current drain from the power supply is approximately 1.3 A; the round- 

 trip resistance of the power leads in the 1.2 kN length of towcable is approximately 

 30 Q,, which results in a voltage loss in the towcable of 45 V. A shunt regulator 

 across the external power supply (B ) inside the in-body instrument housing is used 

 to suppress transients in the towcable due to servo-motor surge. 



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