| MicroSoar Design Details |
| GO TO: | Pressure Case | Analog Electronics | Filter Board | Computer System | Power Subsystem | Sensors | Top of Page | MicroSoar Home Page |
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| GO TO: | Pressure Case | Analog Electronics | Filter Board | Computer System | Power Subsystem | Sensors | Top of Page | MicroSoar Home Page |
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MicroSoar consists of oceanographic microstructure
sensors and electronic subsystems packaged within an aluminum pressure housing.
Machined aluminum end caps with double O-rings seal both ends. The pressure
limit for the case is 8,900 psi, equivalent to 6,000 meters. The recommended
safe operating limit is 1,000 meters, and is determined by sensor O-ring pressure
limitations. The cylinderical pressure case mesasures 26.5 inches long by 7 inches
in diameter. Sensors are mounted in the forward end cap to sample undisturbed water.
Electrical interface connectors are mounted in the rear end cap. Five tapered lead
fairing rings are mounted on the front end cap to streamline the front of the instrument.
The sensor probes project forward through these fairing rings to sample undistrubed water.
Surrounding the probes are four stainless steel probe guards intended to protect the
probes during deployment and recovery. Inside, a center chassis plate divides the
instrument into two main sections: the Computer Electronics Compartment and the Analog
Electronics Compartment.
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MicroSoar attached to a SeaBird 9/11 CTD during testing aboard the Sacajawea. |
| GO TO: | Pressure Case | Analog Electronics | Filter Board | Computer System | Power Subsystem | Sensors | Top of Page | MicroSoar Home Page |
| The Analog Electronics Compartment houses the signal conditioning circuitry for the sensors. There are three assemblies mounted on the chassis plate in this section. The Conductivity Electronics Circuit Board, the Analog Mother Board and the Filter Circuit Board. The forward most circuit board is the Conductivity Electronics Circuit Board. This module has the signal conditioning circuitry for the Capillary Conductivity Probe, it is discussed in more detail below. The long middle circuit board is the Analog Mother Board. The Analog Mother Board is designed to accept Chameleon Analog Electronics plug in modules that provide excitation and amplification for pressure, temperature and acceleration. The Analog Mother Board provides bipolar power supply distribution, four input lines per module and eight output lines for the Chameleon Electronics Modules via mating sockets. The Analog Mother Board has provision for 10 single width Chameleon Analog Electronics modules. The Analog Mother Board features four layer construction with the shields on the outer layers. At the rear of the analog electronics compartment is the Filter Circuit Board. The Filter Circuit Board provides low pass filtering for five input signals. In addition, the output of three of the filter sections can be routed through opamp differentiator circuits. The filters are modules from Frequency Devices that can be pluged into sockets on the Filter Board. Each of the five filter circuits can be configured with either inexpensive DP74 four pole filters or more expensive and higher preformance DP68 linear active filter. The analog signals leave the Filter Circuit Board assembly through a 26 pin ribbon connector and pass through the center chassis panel to the A/D converters in the PC-104 computer stack. |
Analog Electronics Assembles, from the left:
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| GO TO: | Pressure Case | Analog Electronics | Filter Board | Computer System | Power Subsystem | Sensors | Top of Page | MicroSoar Home Page |
| Signals from the Analog Mother Board are routed through the Filter Circuit Board. The Filter Circuit Board provides user-selectable low pass filtering for five of the input signals and straight-through routing for an additional three signals. In addition, three of the filtered signals can be passed to opamp differentiator circuits. The filter sections have been laid out to allow either a Frequency Devices D68 series or a D74 series filter to be installed. The Frequency Devices Filter Modules are fixed-frequency, linear, active, high performance designs that require no external components or adjustments. The D68 series is an 8 pole filter with a wide signal to noise ratio to 16-bit resolution. The D74 is a 4 pole filter with a wide signal to noise ratio to 12 bit resolution. |
Filter Circuit Board with replacable filter modules |
| GO TO: | Pressure Case | Analog Electronics | Filter Board | Computer System | Power Subsystem | Sensors | Top of Page | MicroSoar Home Page |
| The MicroSoar Computer Electronics System provides A/D signal conversion, digital signal processing, digital data routing, 4 gigabytes of on board data storage, external communications, and user interface for testing and diagnostics. MicroSoar makes use of commercial embedded PC-104 computer components. This rugged and compact implementation of the standard PC/AT bus offers full architecture, electronic and software compatibility. PC-104 products feature low power consumption, wide temperature ranges and high reliability. The Ampro CPU Board features a 100 MHz 486DX4 CPU with a 16 bit PC-104 expansion bus, watchdog timer, 12 megabytes of 32 bit DRAM, enhanced BIOS and a hard disk controller (interfacing to the two Model 32100 Western Digital 2 gigabyte hard disk drives). MicroSoar uses two bipolar, software configurable, Analogic AIM 16-1/104 A/D converters featuring a 100 kHz sampling ADC capable of 85 dB dynamic range. |
 PC-104 Computer Components mounted on |
| GO TO: | Pressure Case | Analog Electronics | Filter Board | Computer System | Power Subsystem | Sensors | Top of Page | MicroSoar Home Page |
| MicroSoar typically requires 30 watts at 12 vdc. The source supply must be able to deliver a large inrush current (as high as 6 amps, at 15 vdc) in order for the digital electronics loads to power up reliably. Input power is transformer isolated by three Power Convertibles, Model PWR5300 series, 15 watt switching power converters. These nominal 12 vdc converters can accept an input voltage ranging from 9.2 to 18 vdc. The converters feature high isolation impedence, low noise, regulated outputs, and high efficiency. The converter output commons have been routed separately through connectors so that alternate grounding configurations can be implemented within the wiring harness. An additional 300 vdc to 15 vdc, Vicor converter, is available to allow MicroSoar to accept 300 vdc input power through a long cable. The power conditioning subsystem has been designed to accommodate a diverse set of instrumention voltages, currents, and isolation requirements. |  Computer Power Board (top) and Analog Power Board (bottom) |
| GO TO: | Pressure Case | Analog Electronics | Filter Board | Computer System | Power Subsystem | Sensors | Top of Page | MicroSoar Home Page |
| MicroSoar carries a capillary conductivity probe, a thermistor temperature probe, a static pressure sensor and three single axis accelerometers. The conductivity probe concentrates the electric field from two concentric stainless-steel electrodes in such a manner that all lines of flux must pass through the small hole in the tip of the probe. Probe resistance varies between 200 and 480 ohms over a range of conductivities found in the ocean. The temperature probe, built at OSU, utilizes a Thermometrics series FP07 thin glass-coated bead thermistor. A stainless steel protective sleeve protects the thermister probe tip during handling and deployment. The pressure sensor is an Endevco model 8510B 500 psig piezoresistive pressure transducer with a sensitivity of .5mv/psi. Microsoar uses three IC Sensors model 3140-002 accelerometers, featuring approximately 1 volt/g output response up to 500 Hz (to a maximum of two gravities of acceleration). |
Probes, Capillary Probe, Temperature Probe with
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| GO TO: | Pressure Case | Analog Electronics | Filter Board | Computer System | Power Subsystem | Sensors | Top of Page | MicroSoar Home Page |
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