Aloha Proof Module Design
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Transcript of Aloha Proof Module Design
Aloha Proof Module Design
Cabled Observatory Presentation
School of Ocean and Earth Science and TechnologyFebruary 2006
Purpose
• Proof of Concept
• Long term testing of data communications capabilities.
• Prepare for full observatory phase 2 deployment:– Any modifications learn from phase 1– H4 cable cut and emplacement– Cable termination emplacement
Proof Module Overview
• The proof module has no supervisory command and control.
• The proof module monitors engineering status, data communications, and system operation.
• The proof module has no customers, but includes two internal instruments:– Wide amplitude and frequency range hydrophone– Digiquartz pressure sensor– Continuous pressure spectrum from DC to 40KHz
• The proof module has no time stamp capability, but timing will be accomplished at the shore station.
End Cap w/ DQ and HYD
Microcontroller Power Supply DigiquartzDQ (under) .
Hydrophone ADC Manchester
Top ViewManchester ADC Hydrophone
Microcontroller& DQ Power Supply Digiquartz
Power Supply
• The proof module has a shunt regulator- based power supply consisting of three sections:
– Linear Shunt Regulator
– DC/DC converters
– Filtering
Shut Regulator Section
• Input power to the shunt regulator is 12 VDC at 1.6 amps (20 watts).
• This provides the input voltage to the DC/DC converters.
• All power not used by the DC/DC converters is dissipated in the shunt regulator.
DC/DC converter Section
• The digital and analog electronic circuitry operate from two DC/DC converters:– 5 VDC @ 2 Amps Max– +/- 12 VDC @ .33 Amps Max
• Due to the switching characteristic (noise) of DC/DC converters this section is enclosed in the emission-shielding metal box.
• Box penetration feed-thru capacitors are used for all DC voltage and return wires.
• Temperatures are monitored and also penetrate the box using feed-thru capacitors.
Filter Section
• A final section inductor/capacitor filter is used to provide clean noise free power.
• The hydrophone is being operated with a wide amplitude dynamic range of 24 bit ADC capability.
• The power supply filtering is for the analog sections:– hydrophone preamplifier, and – hydrophone analog to digital converter.
Communication
• The instrument data is provided over 12.288 MHz, Manchester encoded/decoded data stream.
• This is 96,000 – 64-bit frames/second.• Within each frame are:
– Two 24 bit digitized analog channels of the hydrophone.
– Two single bit RS232 embedded serial communications 9600 baud. One primary and a secondary backup.
– Six bits for frame synchronization.– Eight unused (zeroed) bits.
Digiquartz
• The Digiquartz is a digital pressure gauge.• 32 bit counters
– Raw count (for high resolution with long periods)– Period count (for quick updates at lower resolution)
• Depth is calculated from the 32kHz variable pressure sensor where frequency is directly proportional to depth.
• Resolution is directly proportional to the integration time.• Temperature compensation is calculated from the
170kHz variable temperature sensor where frequency is directly proportional to temperature.
• The Digiquartz is the same used in NOAA DART buoys to detect tsunami
Hydrophone & ADC
• The analog signal from the hydrophone is digitized with a two channel 24 bit ADC.
• Channel 1 (seismic) is a wide frequency range from 100 seconds to 40 kHz.
• Channel 2 (audio) is a narrow frequency range from 10 Hz to 40 kHz.
• With digital sampling is 96,000 samples per second the analog is low pass filtered at 40 kHz to minimize aliasing.
Serial Data Stream
• The serial data stream provides both engineering and Digiquartz data.
• Engineering data:– 5 DC/DC power supply voltages– 2 cable and sea water return voltages – 1 current of H4 cable– 4 temperatures
• Diqiguartz data:– 2 depth & temperature period counts– 2 depth & temperature free run counts– Calculations of depth with temperature compenstaion
Sample Serial Stream