INSTRUMENTATION 



Although it was not the intent of this study to analyze 

 requirements for instrumentation and data transmission^ it 

 was impossible to omit such considerations completely. 

 Studies related to typical instrumentation housing and infor- 

 mation transmission led to the design of a system for moni- 

 toring the temperature and pressure at many points along 

 the cable. Some of the critical circuit elements were 

 "breadboard ed" to check the design, A detailed description 

 of the instrument circuitry is given in Appendix III, In 

 this system^ binary coding is employed to make possible the 

 sequential sampling of 128 sensing gages by the use of only 

 seven wires for gage selection, one wire for gage output, 

 one wire for calibration, and one wire for power. The ground 

 return is provided either by an additional wire or by the 

 steel jacket and the seawater. The number of sensing gages 

 may be doubled for each additional gage-selection wire, A 

 feature of the system is that failure in one of -Uie instrument 

 packages will not affect theoperation of the rest of the system. 



Although this instrument system offers distinct advan- 

 tages over a co-axial FM telemetering system,, there is no 

 reason why a system employing coaxial cable could not be 

 designed. The only requirement to be met is that the 

 electrical conductor must be small enough to occupy the 



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