NEPTUNE Power System Controller Preliminary Design Review Tim McGinnis Dec 4-5, 2003

Functional Requirements Monitor input and output voltages and currents Control internal & external Loads Measure internal & external load voltages & currents Detect and isolate external load ground faults Monitor engineering sensors Communicate with shore PMACS through DCS Allow application code to be maintained from shore Solid state, non-volatile memory Rugged, reliable, long life Reasonable packaging Good thermal characteristics

Controller Specifications PARAMETERSPECIFICATIONSVERIFICATION Input Power Supply Voltage:+5VDC, +/-12VDC Design Digital Outputs> 48 channelsDesign External 48V, 400V, 16 deadface relays Internal Loads16 at 12V and 48V Analog Inputs>40 channels, bit Design Voltage Monitoring10kV, 400V and 48V busses Current Monitoring 10kV External 48V, 400V, 12 bit Internal 12V or 48V, 12 bit Engineering SensorsTilt, temperature, pressure Ground Fault Monitoring 48V and 400V bus, <10 μA resolution Over-current ProtectionProgrammable by userTesting Data Interfaces Available Design Primary10/100BaseT Ethernet Secondary RS232 Serial data MemoryNon-volatile program code memory Design SoftwareProgram code changeable from shore Design

Mechanical Requirements PARAMETERREQUIREMENTCOMPLIANCE Thermal Management:Immersed in Flourinert Analysis and Testing Dimensions TBDDesign Connectors TBDDesign MountingTBDDesign Environmental Requirements PARAMETERREQUIREMENTCOMPLIANCE Temperature range per Neptune Power System Analysis and Testing Requirement Document Humidityper Neptune Power System Analysis and Testing Requirement Document EMC and EMI per Neptune Power System Analysis and Testing Requirement Document Shock and vibration per Neptune Power System Analysis and Testing Requirement Document PARAMETERREQUIREMENTCOMPLIANCE Lifetime 30 yearsDesign, Modeling and Accelerated Life Testing FIT Rate1000 FITS (?)Design, Modeling and Accelerated Life Testing Mission Assurance Requirements

Number of Analog Input Measurements Voltage –10 kV bus – 1 –400 V bus – 1 –48 V bus – 1 Current –10 kV bus – 1 –400 V external loads – 8 (4) –48 V external loads – 8 (4) –48 V internal loads – 16 Ground Fault Current –Low Voltage Buses - 2 Engineering –Pressure – 1 –Tilt - 2 –Temperature – 3 (?) Total –Voltage = 3 –Current = 33 (25) –Ground Fault = 2 –Engineering = 6 (?) –Total = ~44 (~36) Note: MARS requirements shown in parentheses

Number of Digital Output Controls External circuits –400 V loads = 8 (4) –400V load deadface = 8 (4) –48 V loads = 8 (4) –48V load deadface = 8 (4) Internal Circuits –48 V loads = 16 Total –External = 32 (16) –Internal = 16 –Total = ~48 (~32) Note: MARS requirements shown in parentheses

COTS Hardware Form Factors PC-104 –3.5” x 3.8”, stacking connector –Lots of I/O options –Used in commercial, military and space applications –Reliability data generally not available –~$2500/system

COTS Hardware Form Factors 3U VME / Compact PCI –4” x 6.3”, euro-card connector/backplane –Lots of I/O options –Reliability data available, MTBF’s khrs (CPU) –~$20k/system –available with conduction cooling

COTS Hardware Form Factors 6U VME / Compact PCI –9” x 6.3”, euro-card connector/backplane –Lots of I/O options –Reliability data available, MTBF k-hrs (CPU) –available with conduction cooling –Large size

Broad Reach Engineering Builds control systems for satellites and other space applications Could provide high reliability integrated system Can provide any level of quality/reliability from prototype-engineering- flight Development and “flight” system ~$ k

PowerPC Processor Reliability 100 FITS = 100 failures in 10 9 hours = 10 7 hrs MTBF = 1100 yrs MTBF

COTS Reliability Reality ItemFITsMTBF (hrs) Power supply7891,267,427 Filter5231,912,045 Backplane 3482,873,563 CPU 3, ,929 I/O 5, ,495 30°C 11,307 88,428 12°C 8, , 956 Radstone 3U cPCI data shown

Software Operating System Choices –DOS –LINUX: GPL, Real Time Extensions –Proprietary: VxWorks, QNX, Lynx, Integrity Application Code –Most likely C/C++

VxWorks Commonly used by Military & Space Recommended by JPL Board Support Packages (BSP) available for most vendors CPU Large footprint Proprietary

GPL LINUX Gnu Pubic License Open Source Compact, high performance May require BSP and driver development Full control of OS source code –Can’t be retired Requires self support –Achievable but takes man power

Real Time LINUX Shares many features with GPL LINUX Fast, predictable real-time response. Guarantees availability of CPU and network resources for critical tasks, even in overload conditions.

Operating System Costs Developer License Deployed Unit Cost BSP Adaptation 2 Dev + 2 Dep 5 Dev + 25 Dep RT Linux4,800025,00034,60049,000 GPL Linux0025,000 VxWorks7, ,55041,375 If Board Support Package (BSP) not available, “free” Linux can be expensive option for low quantities

Action Items Confirm Functional Requirements of Controller and other relevant sub-systems Complete Trade Study to compare options Select Controller hardware Determine development system requirements Write specification and procure development system Start software development Procure MARS deployment hardware