With the water still, the unit may be balanced by 

 depressing the OPERATE-BALANCE switch and advancing the 

 SENSITIVITY control as far as possible with the recording 

 stylus remaining on the paper . Then the CAP. BALANCE and 

 RES, BALANCE are alternately adjusted to obtain a minimum 

 indication on the recorder The SENSITIVITY is then advanced 

 and the process repeated . This operation is repeated until 

 a null indication Is obtained on the 0.6-Inch full-scale 

 SENSITIVITY step. The OPERATE-BALANCE switch is then 

 released. The SENSITIVITY control is then rotated back to 

 OFF and the position to which the stylus shifts is noted. 

 The SENSITIVITY control is then rotated back to the 0.6- 

 inch full-scale step, and the CAP. BALANCE control (or 

 controls, if necessary) rotated until the stylus shifts to 

 the same position to which it moved when the SENSITIVITY 

 control was placed in the OFF position. The stylus will 

 then be found to stay in the same place when the SENSITIVITY 

 control is rotated, provided that the bridge remains in 

 balance. The SENSITIVITY control is then placed on the 

 desired step and the stylus positioned to the center of the 

 paper (or to the desired zero position) by means of the 

 STYLUS POSITION control. 



In calibrating the system, the SENSITIVITY control 

 should be turned to the 4-inch full-scale step. This is 

 because the calibration built into the unit represents a 

 change in water depth of approximately 2 inches in each 

 direction, or a total of 4 inches. After calibration, 

 the SENSITIVITY control may be returned to the desired 

 position. The system is then ready for use. 



MAINTENANCE 



The electrical components in the Type 286-1A Dynamic 

 Wave-Height Recorder are all operated well within their 

 ratings and should give very little trouble. The console 

 has a blower for cooling. 



Cables should not be walked upon nor permitted to 

 stay in the water. 



The gage should be cleaned occasionally with a soft 

 cloth. This is necessary to remove the foreign matter that 

 collects on the wire. Holes in the enamel have the effect 

 of a leaky dielectric and prevent the proper balancing of the 

 bridge. These holes will seldom be found in a new wire, but 

 will sometimes develop after use. In the extreme case, they 

 are evidenced by the inability to reach a resistance balance 

 of the bridge. 



6 



