silicone potting gel separates the sensor from the electronics. The bulk of the 

 pressure sensor is contained within a capped 18.5-cm-long by 6-cm-diam 

 galvanized steel pipe, with the threaded stainless steel transducer housing 

 fitting through one endcap. A bulkhead connector on the other endcap accepts 

 a transmission cable, which is connected to conditioning and controlling cir- 

 cuitry, where the sampling rate is controlled and the signal is digitized and 

 combined with the concentration profile data. 



PC array. Two personal computers (PC's) were used throughout the data 

 collection process. PCI, in Figure 9-3, was solely used for receiving and 

 storing the data streams as they came from the ACP and BASS microproces- 

 sors. PC2 was used primarily for performing an elementary analysis of 

 10-min samples of wave runs which were written to a floppy disk during each 

 run on PCI. PCI contained software pertinent to receiving the serially trans- 

 mitted data to a named file, as well as the software for reading the WWV 

 (broadcast by National Institute of Standards and Technology, Fort Collins, 

 CO, call letters WWV) time signal and storing data to magnetic tape. PC2 

 contained software applicable to data analysis including a FORTRAN compiler 

 and Matlab™, a numerical computation package. 



PCI was a 33-MHz, 386-based microprocessor with serial ports connected 

 to the instrument data streams. Extra hardware was installed for the magnetic 

 tape drive and the WWV time signal. PC2 was also a 33-MHz, 386-based 

 microprocessor, but was not connected to any of the instruments. Both ma- 

 chines contained one 5V4-in. and one 3V£-in. floppy disk drive and were con- 

 nected to VGA color monitors. 



Other instruments. Other important instruments to the data collection 

 process include a 24-V power supply used to power the ACP and BASS mi- 

 croprocessors and transducers. An oscilloscope was used to examine the 

 instantaneous signals from the ACP to monitor the reflections from the profile 

 range bins. A self-contained, high-density magnetic tape drive was employed 

 for permanently storing data from PCl's hard disk. 



Location 



The ACP, BASS, and pressure sensor were located close together on a 

 specially designed mounting apparatus. Generally, the sensors were located 

 between SUPERTANK Stations 18 and 19 for all wave runs, in close proximi- 

 ty to instruments belonging to other members of the offshore group. The 

 specific location of the instruments with respect to the stations and other off- 

 shore group devices for each wave run are given in Table 9-1 and Figure 9-4. 

 The locations of the instruments with respect to the edge walls, again for each 

 run, are given in Table 9-1 and Figure 9-5. 



The mounting assembly holding the ACP, BASS, and pressure sensor is 

 shown in Figure 9-6. The assembly consists of aluminum seats for the ACP 

 and the BASS frame assembly, with the instruments attached to their seats 



Chapter 9 The Ohio State University Measurements 



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