ATTITUDE SENSOR 

 DIGITAL TAPE RECORDERS 



PINGER/TRANSPONDER 



SURFACE ACTUATED 

 RADIO BEACON 



DATA 



CONDITIONING 



EQUIPMENT 



SETTLEMENT 

 SENSOR 



RECOVERY 

 FLOATATION COLLAR 



ACOUSTIC COMMAND 

 RECEIVER 



XENON FLASHER 



RELEASE COMMAND 

 DECODER 



RELEASE TIMER 



U ISOLATING TUBE AND 



U __ REFERENCE PROBE 



Figure 3. Artist's conception of NCEL automated performance monitoring 

 device, LOBSTER. 



Another automated monitoring device is the NCEL Foundation 

 Performance Monitoring System (FPMS) (Figures 5 and 6). The FPMS, 

 which is composed of a Foundation Monitor and an Amplification Module, 

 is designed for general use on a structure of any size, shape, and type (such 

 as mat, spread footings, or piles). The system monitors vertical movement 

 (settlement) by sensing the change in pressure head between the Foundation 

 Monitor and the Amplification Module as the Foundation Monitor settles 

 relative to the Amplification Module. The Amplification Module is physically 

 isolated from the effects of the structure (by a distance of about 30 feet). 

 The Foundation Monitor also records the differential movement of the struc- 

 ture by utilizing two tilt transducers mounted at right angles to each other 

 within the Foundation Monitor. As the structure tilts or rotates, the Foun- 

 dation Monitor and tilt transducers undergo a similar movement. Precision 

 of vertical settlement readings is better than 0.05 inch, while precision of 

 tilt readings is better than 2 minutes. The Foundation Monitor, which can 

 be deployed in up to 6,000 feet of water, senses the tilt and pressure transducers 

 at various time increments (short during initial phase; longer during latter phase). 

 Once the appropriate transducers are sensed, the Foundation Monitor conditions 

 and stores the digitized data on magnetic tape for later processing. 



