3. Check to see that the ac plug, dc power supply cable (P,S.) and deck cable 

 (from the towcable) are properly connected to the rear of the control unit. A read- 

 out of the depressor stabilizer angle, depth and delta depth may be obtained by in- 

 terconnecting between the control unit and a voltmeter or preferrably a multi-channel 

 strip chart recorder. 



4. Connect the three power plugs from the control unit, Kepco power supply, 

 and the function generator to a 110 V, 60 Hz power source. 



5. Turn the ON-OFF switch of the control unit to ON. 



6. Turn on the power switch of the Kepco power supply and adjust the voltage 

 control to obtain 1.3 to 1.6 A on the ammeter. 



7. Turn the LINE switch of the function generator on ON. 



The system is now active and can be operationally checked on deck as follows: 



1. Adjust the RANGE VERNIER potentiometer of the control unit from 0500 to- 

 wards a 000 reading (counterclockwise rotation) and at some point near zero the flap 

 should start to move. When the flap moves to a new position observe the current 

 reading of the Kepco power supply; it should increase towards 1.5 to 1.7 A when 



the flap is actually moving and may drop to 0.6 A when the flap is at rest but not 

 at a limit position. 



2. Adjust the OUTPUL LEVEL control on the function generator to cause the flap 

 to oscillate synchronously with the frequency setting of the generator. 



3. The measurement of flap angle, depth, and delta depth may be obtained using 

 a strip-chart recorder and setting the sensitivity of the recorder to obtain the 

 cal-step readings listed in Table 4. The calibration sequence is ZERO CHECK (ZC) , 

 CALl (CI), and CAL2 (C2) . The electrical calibration steps are generated by 

 momentary depression of the CAL START pushbutton on the control unit. 



TOWING OPERATION 



The amount of towcable length will depend upon the maximum desired towing depth 

 and to a lesser extent on the towing speed. For best dynamic performance, the 

 depressor should be operated at near maximum coefficient of tension (C max = 1.5). 

 Also at high tension coefficients the vertical separations of the remote sensors will 

 remain more nearly constant during cyclic depth control (Figure 20) . The proper 

 operating condition can be achieved using the following procedure. 



60 



