Wiki

##Introduction

This page gives an overview of SCINI's power and communications electronics, both on the topside (surface), and on SCINI herself. Detailed schematics, datasheets, PCB layouts, and more can be found in the Electronics Repository linked above.

Circuit and PCB layout was done using a combination of EagleCAD and PCB Artist which can both be downloaded for free.

Not all of the original schematic files could be found, but PDF versions of the schematics are available and in their respective folders.

##Systems

###Topside SCINI's power and communications structure is inherently mobile and designed for rough Antarctic field campaigns. Her entire Command & Control (C&C) system fits inside a Pelican 1770 Case, aptly called the Command Center.

The command center in action during a 2014 deployment through the Ross Ice Shelf (~36 m of ice). Photo Credit: Peter Rejcek, Antarctic Sun

Data wiring diagram for the command center.

Higher resolution wiring diagrams

###Vehicle Power and communications are supplied to SCINI using 240VAC with Ethernet Over Power to supply TCP/UDP communication. The 240AC is converted to 300VDC using a Vicor FARM; this 300VDC line provides power between the main and camera bottles. Several Vicor DC-DC converters supply 24, 15, and 12 volts to different sub-systems throughout the vehicle.

##SCINI PCBs

###Controller Board The Atmel ATmega 238P is the microcontroller used throughout SCINI. The main bottle contains two ATmega328s, which are responsible for temperature & humidity sensing, thruster commands, pressure (depth) measurements, tilt/roll/sway, and AC line voltage measurement. The 328 in the camera bottle is responsible for the camera tilt, light & scaling LASER control, temperature & humidity sensing, and control of an (optional) external gripper arm.

Schematic for the Controller Board

###Vicor FARM Board The Vicor FARM Board converts the 240VAC provided from the tether to 300VDC, to be distributed and later down-converted to 12, 15, and 24V. Special care is taken to filter the AC line as it has the Ethernet Over Power signal modulated atop it. This is accomplished using a Delta Electronics 06DHAG5 EMI Filter in series with the FARM.

Schematic for Vicor FARM Board

###Vicor 15VDC Board All of SCINIs thrusters run on 15VDC provided by a 300W Vicor DC-DC converter. 15VDC is provided to the Electronic Speed Controllers (ESCs) on the ESC Distro Board, noted below.

Schematic for VICOR 15vDC Board

###Vicor Dual 12/24VDC Board Within the camera housing, two smaller Vicor Micro DC-DC converters provide 12 and 24VDC to power SCINI's lights, gripper, microcontrollers, and Elphel cameras.

Schematic for VICOR Dual 12/24VDC Board

###ESC Distro Board The ESC Distro Board is nothing more than a 15VDC bus upon which all SCINIs motor controllers are both mounted and powered. Molex connectors connect to each thrusters three-phase wiring. Power from the 15V Vicor is provided to the Distro Board via 15A Anderson Power Pole connectors.

Distro Board showing the main thruster ESC, Anderson connector, and mounting pins for tunnel thruster ESCs (right side).

###X-Port Board A Lantronix X-Port server is responsible for serving (conterting) TCP/IP communications to TTL logic. A small 8-pin DIP chip MAX3430 converts TTL logic to RS-485 which then gets distributed throughout SCINI, and upon which the three microcontrollers sit.

X-Port Schematic

##Underwater Cables SCINI uses 8-pin MC style connecters and bulkheads for all underwater power and communications connections.

Cable drawings can be found here

Cable pinouts can be found here

##Main Thruster SCINIs main thruster is a modified VideoRay Brushless Thruster. The tether connection comes through the thruster, where it is connected to another 8-pin cable that goes to the main bottle. The back-end of the housing is potted in Hysol E-90FL for an inexpensive (and flush) "endcap." All wires are potted in the E90, and only the three motor wires are exposed (wither gold-plated barrel connectors) on the inside of the housing.

This wiring diagram shows connections into and out of the main thruster housing.

SCINIs main thruster with the E-90FL potting visible. Shown without motor shaft.