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Ground Based Observatories (GBO) Observatory System Design Stewart Harris - UCB

Ground Based Observatories (GBO) Observatory System Design Stewart Harris - UCB. System Design Summary. Presentation Overview: Observatory Specifications GBO Observatory Components Power Control Unit Temperature Control Power Control Instrument Data Acquisition and Transmission

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Ground Based Observatories (GBO) Observatory System Design Stewart Harris - UCB

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  1. Ground Based Observatories (GBO)Observatory System DesignStewart Harris - UCB

  2. System Design Summary • Presentation Overview: • Observatory Specifications • GBO Observatory Components • Power Control Unit • Temperature Control • Power Control • Instrument Data Acquisition and Transmission • System Computer • Satellite Communication • Environmental Enclosure • Requirements • Design

  3. Internet GBO Components Iridium All Sky Imager in Enclosure GPS Telesat Dish Computer System Enclosure&Observatory Support Electronics GMAG • Variations possible at some sites: • Existing magnetometer • Enclosures not needed • Existing Internet connection MainAC Power

  4. Ground Site Requirements

  5. Observatory Requirements

  6. System Electrical Overview

  7. Rack Mount Shipping Case System Computer GMAG Interface Electronics Hot Swap HDD Space available for modems UPS 28” Prototype OSE Layout

  8. Power Control Unit CR10X Datalogger UPS Camera Power Supply CR10X Battery Prototype OSE Layout (2)

  9. Power Control Unit (PCU) The PCU provides control of both Temperature and Instrument Power • Design Approach • Provide temperature environment inside Computer Enclosure and ASI that enables use of standard commercial hardware for computer, USB hard drives, Telesat/Starband gear, etc. • Maintain internal temperatures at 20º ± 10º C • Implement graceful shutdown in either event of: • Loss of Power • Loss of Temperature (either too high, or too low) • In the event of extended power loss, power control must allow for temperature to stabilize prior to re-boot • Select “Smart” controller (CR10X) vs Thermostat approach • Programmable with remote access via Internet or Iridium • Provides analog I/O, digital I/O for System Computer • Extended temperature range (-55º to +85ºC) • Always operating and accessible • Low power consumption (battery can operate it for months) • Simple programming and data logging capability

  10. Heating and Cooling Control ASI Heater CSE Cooler CSE Heater Temperature Sensors ASI CSE Outside VLINE Main AC CB1 SSRs CR10X Power Control Unit System Computer AC Power Digital I/O Serial I/O Analog I/O

  11. CSE Heating / Cooling Devices Solid State Air Conditioner 163W Capacity 120VAC Power Small Space Heaters 175W, 120VAC, 2 ea

  12. ASI Heating Devices Heat Blankets 120W, 120VAC, 2 ea

  13. System Power Control • CR10X can initiate System Shutdown: • Monitors voltage (VLINE) and temperature (TCSE) continuously • Flag System Computer to shutdown via serial line protocol • In event of power loss • Monitors time “on-battery”, flags shutdown after 60 (TBR) min. • When power returns, allows temperature to stabilize, then restores System Power • In event of temperature loss (either too cold, or too hot) • Initiates immediate shutdown • Restores System Power when temperatures within limits

  14. Internet Instrument Data Flow ASI System Computer Hot Swap Hard Drive(s) GMAG Telesat Modem GPS USB Serial I/O 10/100 Base T

  15. System Data Collection • System Computer Selection • Hardware features: see next slide • Compatible with a Linux standard installation • Reasonably low power (30 – 40W) • Reasonable size • Alternatives examined: • Databrick (MobilePIII 700MHz) – used in Prototype • Thermal issues, requires modification to include a fan • SC240 Mini-ITX based (VIA chipset 600MHz C3) • Concerns about VIA support in future Linux upgrades • Fanless! • Nova7895 based (PIII 866MHz) • Rather large, but workable • More expensive than SC240

  16. Computer Comparison USB v2 USB v1 LAN Serial COMPUTER PORTS NEEDED GMAG 1 GPS 1 ASI 1 Swappable HDD 1 Satellite Internet 1 CR10X 1 1 Single Piece Price Custodian Connect POWER COST TOTAL NEEDED 2 2 1 2 COMPUTER PORTS AVAILABLE Databrick 2 2 0 1 32W $1317 $940 SC240 4 0 4 2 39 1Firewire $1216 NOVA-7895 3 2 2 ?

  17. Remote Intervention • Two Levels: • Typically GBO accessed via Internet • Hardwired in several locations • Using local LAN connection • Telesat HSi (Canada) or Starband 480 (Alaska) • Can provide fixed IP address • Tests indicate about 10kbps sustainable uplink rate • Under duress, Back up communication via Iridium • Reserve for remote locations? • 2400 bps

  18. UCB Iridium Connection Serial I/O System Computer Supervisor Channel 1 Serial Port Switch Iridium Modem CR10X Supervisor Channel 2

  19. The Environment Summer and Winter USGS Tundra monitoring site Alaskan Tundra

  20. Enclosure Concept “Box within a Box” Internal Rack Mount for Equipment (Doubles as Shipping Case) External Insulated Environmental Enclosure

  21. Computer Sys. Enclosure (CSE) • Requirements: • House Observatory Support Electronics in Controlled Environment • ASI, GMAG, Computer, Communications, Control, etc. • Maintain internal temperature at 20º ± 10º C • Operate in external ambient of -50º to +40ºC • Provide “dust-free” method of cooling when required • External Cable access via “stuffing tube” • Provide access door for Hard Drive Hot Swap • Provide access for maintenance • Ruggedized and shock protection for transportation

  22. Prototype Computer Enclosure

  23. Heating Required: Outside temp: -60º C Inside temp: +10º Heat added: 165 W Cooling Required: Outside temp: +50º C Inside temp: +40º Heat to remove: 80 W Heating/Cooling Needs Assumptions: Enclosure dimensions: 34” (h) x 44” (w) x 44” (l) Thermal resistance (R-value): R-12 Internal power dissipation: 47 W Prototype GBOAthabasca

  24. Athabasca 4/15/04 courtesy M. Greffen Prototype Findings • Prototype CSE Deployment: • Current design size is larger than necessary. • Prototype size: 43” (L) x 45” (W) x 38” (H) • Could be smaller for easier transport. • Minimum size: approx. 37” (L) x 40” (W) x 38” (H) • “Awning” design needs improvement. • Keeping it warm inside has proven to be easy • Keeping it cool inside may be more difficult, but the solid state A/C seems to work.

  25. END

  26. CR10X Software: Table of Instructions Loops on fixed interval High level instructionsExample PCU Programming

  27. System Power State Diagram

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