TEAM BRIGHTRIDERS Failure Modes, Effects, and Criticality Analysis “We put the SOUL in SOULAR racing”

Power Circuits

Failure No. Failure ModePossible CausesFailure EffectsMethod of Detection Criti- cality Remarks A1V DD5v = 0vSwitching regulator circuit component failures, internal or external shorts, under voltage or disconnect on voltage supply line Telemetry System cannot operate.ObservationHigh A20v < V DD5v < 4.2vSwitching regulator circuit component failures, internal or external shorts, under voltage on supply line Microcontroller has an under-spec voltage supply for the operating frequency. The Telemetry System may not operate. ObservationHigh A34.2v < V DD5v < 4.5vSwitching regulator circuit component failures, internal or external shorts, under voltage on supply line RS232 Tranciever and CAN Tranciever under voltage spec and may not operate, Accelerometer out of calibrated range. ObservationHigh A4V DD5v > 5.5vSwitching regulator circuit component failures, internal or external shorts, over-voltage on supply line All 5 volt components are over voltage spec, possible hardware damage, excess heating or failure to operate. ObservationHigh

Power Circuits Failure No. Failure ModePossible CausesFailure EffectsMethod of Detection Criti- cality Remarks B1V DD3.3v = 0vLinear regulator failure, internal or external shorts, under voltage or disconnect on V DD5v SPI-to-UART chips cannot operate, Telemetry system will be unable to communicate with the Battery, Motor, and GPS. ObservationHigh B20v < V DD3.3v < 3.0vLinear regulator failure, internal or external shorts, under voltage on V DD5v SPI-to-UART chips are under voltage spec, Telemetry system may be unable to communicate with the Battery, Motor, and GPS. ObservationHigh B3V DD3.3v > 3.6vLinear regulator failure, internal or external shorts, over-voltage on V DD5v SPI-to-UART chips are over voltage, Telemetry system may be unable to communicate with the Battery, Motor, and GPS, as well as possible hardware damage and excess heating. ObservationHigh

SPI-to-UART and RS-232 circuits

Failure No. Failure ModePossible CausesFailure EffectsMethod of Detection Criti- cality Remarks C1No data received by chase car Packet modem out of range or unoperational, UART module of microcontroller unable to transmit, RS232 transceiver failure, software bug The Telemetry System is unoperational. ObservationHigh C2Failure to enter diagnostic mode Packet modem out of range or unoperational, UART module of microcontroller unable to receive, RS232 transceiver failure, software bug Diagnostic mode is unavailable, but the major part of the Telemetry System is functional. ObservationLow

SPI-to-UART and RS-232 circuits Failure No. Failure ModePossible CausesFailure EffectsMethod of Detection Criti- cality Remarks D1Invalid or missing data from Battery SPI-to-UART chip failure, SPI-to-UART chip select stuck high or low, crystal circuit failure, RS232 transceiver failure, SPI module of microcontroller failure, cable disconnect, software bug Driver unable to read and manage battery levels. Possible battery over-charge. Communicati on tested during self- test High D2Invalid or missing data from Motor SPI-to-UART chip failure, SPI-to-UART chip select stuck high or low, crystal circuit failure, RS232 transceiver failure, SPI module of microcontroller failure, cable disconnect, software bug Unable to log motor data for performance analysis. Communicati on tested during self- test Low D3Invalid or missing data from GPS SPI-to-UART chip failure, SPI-to-UART chip select stuck high or low, crystal circuit failure, RS232 transceiver failure, SPI module of microcontroller failure, cable disconnect, software bug Unable to log GPS data for aerodynamic analysis. Communicati on tested during self- test Low

Analog Circuits

Failure No. Failure ModePossible CausesFailure EffectsMethod of Detection Criti- cality Remarks E1Invalid or missing data from Acceleromete rs Accelerometer failure, A/D module of microcontroller failure, improper alignment of telemetry system, software bug. Unable to log acceleration data for aerodynamic analysis. Operation and validity tested during self-test Low E2Invalid or missing data from Temperature Sensor Temperature sensor failure, A/D module of microcontroller failure, software bug. Unable to log internal car temperature for analysis. Operation and validity tested during self-test Low

Microcontroller and CAN circuits

Failure No. Failure ModePossible CausesFailure EffectsMethod of Detection Criti- cality Remarks F1Microcontroller does not operate Bypass capacitor failure, crystal circuit failure, microcontroller failure, power circuit failure, software bug The Telemetry System is unoperational. ObservationHigh

Microcontroller and CAN circuits Failure No. Failure ModePossible CausesFailure EffectsMethod of Detection Criti- cality Remarks G1CAN module cannot transmit CAN transceiver failure, CAN module failure on microcontroller, power circuit failure, cable disconnect, software bug. Driver interface unable to update. Driver unable to read and manage battery levels. Possible battery over-charge. Communicati on tested during self-test High G2CAN module cannot receive CAN transceiver failure, CAN module failure on microcontroller, power circuit failure, cable disconnect, software bug. Unable to log maximum power point tracker data for performance analysis. Communicati on tested during self-test Low