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Low Voltage Cable Reflectometer Built in Test Module



OBJECTIVE: Develop a modular circuit board which implements a low voltage reflectometer capable of determining cable faults and reporting results back to a processor or Field Programmable Gate Array (FPGA) as part of Built in Test (BIT) circuitry.Goal is to demonstrate a cable test technology for integration at the circuit board level for new electronics equipped with data, power, and antenna cables that are human, aircraft or vehicle mounted (not long distance transmission).

DESCRIPTION: Improved and simplified troubleshooting of electrical systems constitutes a fundamental component of sustainment, which falls under soldier lethality, one of the six army modernization priorities of the Army.PM Air Warrior is developing the next generation of body mounted electronics for the aviator.Previous development efforts ran into substantial reliability issues with body mounted cables due to their tendency to flex and crimp far more than what is seen on an air or ground vehicle.Cable and connector issues were a big contributor towards an unsuccessful conclusion of that program.The Rapid Innovation Fund topic “Wireless Air Soldier Power” is developing a power and data hub through which all body mounted cables will be connected.While digital BIT is implemented, analog wire testing is not part of the current design approach.The Office of the Secretary of Defense (OSD) recently polled the development program managers Army wide for feedback on the deployment and use of test equipment designed to identify intermittent faults in electronics.Due to the weight and cost of external support equipment capable of this, plus the training associated with adjusting the results for the equipment under test, an external test set is not desired.Instead, an internal test which allows the user to know if the system has problems prior to mission start is needed providing immediate go/no-go status of cabling which includes assessment of whether wire performance is likely to experience intermittent failures if signals show weak spots.While cable test reflectometers have been around for many years, methods that work with much lower voltage have recently been developed that can test external cables from a central box using an approach integrated inside the box.Research on this includes the following citations: solicitation intends to identify existing low voltage cable assessment test equipment and incorporate this technology into a modular chip capable of introduction to a circuit board with the following features identified:(1)Recommend interface for standardized chip to communicate with processor or FPGA. (2) Cable types that can be evaluated (single strand, twisted pair, coax, Twinax, etc.) (3) Upon verification of working system operation after initial installation, perform a baseline assessment of existing cable performance. (4) Upon startup BIT for all subsequent power on to system, perform assessment of existing cables and compare to assessment of initial verified operational cables.If significant deviations found, provide code to processor or FPGA corresponding to which connector and pin is found to be a potential problem.

PHASE I: This effort shall develop and demonstrate a breadboard prototype circuit board capable of identifying fault types of different cables connected to the circuit board to include short circuits, open circuits, and intermittent faults due to loose or damaged pins in connectors.A laboratory demonstration is required to demonstrate breadboard operation of the circuit board and show proper fault analysis when faults are introduced.A test plan is required showing how faults will be introduced to the cables and what faults can be detected by the tester.A test report is required documenting the results of the laboratory demonstration and the accuracy of the fault detection actually achieved by the circuit board.The contractor shall write and deliver a plan for a Phase II integration of the circuit board into the power and data hub.The integration plan shall project cost, size, weight, and power consumption of the circuit board to be integrated into the power and data hub based on the breadboard build prototype.

PHASE II: The contractor shall partner with the vendor building the power and data hub to design a modification introducing a circuit board prototype to deliver a new power and data hub that can automatically detect cable faults as part of the power up sequence for BIT, and allows a “calibration” function that the user can implement when a working set of cables and subcomponents are mated to the hub.A total of not less than eight hubs with the fault detection chips introduced shall be built and delivered.An interface control document shall be provided to the Government and the hub vendor detailing mechanical and electrical interface for the fault detection module.The HUB vendor shall have project management control of weight/space/power assignment of the fault detection module integration.The contractor shall host a Preliminary Design Review and perform a Critical Design Review (CDR) at the Government’s facility in month eleven.Critical Design Review (CDR) shall serve as the first milestone at the end of year one.Both design reviews shall make projections for weight/space/power requirements of the fault detection module.CDR shall present a cost projection for the fault detection module.Design reviews shall address how the fault detection module will have access to all hub connector wires without interference in normal operation, automatic activation when BIT is initiated, automatic disable of module operation when BIT is not active, how faults will be reported to hub processor, and an assessment of fault determination and accuracy.Delivery of fault detection modules to the HUB vendor for integration shall serve as the 2nd year milestone.The contractor shall provide technical support to the HUB vendor by phone and travel to the hub vendor site for first integration build activity.The contractor shall design the fault detection module as a circuit board module within the hub.The contractor shall provide final measured fault detection module capability and weight/space/power information to the hub vendor so that the product specification for the hub can be updated.The contractor shall perform a bench demonstration of the first fault detection module built to verify space/weight/power, functions, and capability.Deliverables will include briefing slides for the design review, meeting minutes for bi-weekly status telecons and design reviews, a test plan for fault detection module performance demonstration showing compliance to hub integration requirements, test report documenting test accomplishments, data for updated hub performance specification reflecting measured fault detection module performance, and a report detailing projected cost of the final fault detection module design as a function of quantity from a minimum of 50 and up to 1000 at a time.A preliminary technical data package for the fault detection module shall be delivered.

PHASE III: Develop production processes for fault detection module prototypes built and delivered in Phase II.Update the hub item specification to reflect final production process weight and performance impact based on production configuration fault detection module.Build thirty six (36) production representative fault detection modules to supply to hub vendor for final operational testing on multiple US Army helicopter configurations.Provide technical data package for fault detection module.Fault detection module may migrate into other Army avionic boxes under development.Primary commercial application of fault detection module may focus on vehicle wire harness interface to central computers, dedicated controllers for industrial machines with complex wire harnesses, and network hubs delivering Power Over Ethernet (POE).

KEYWORDS: Intermittent Cable Fault Detection, time domain reflectometer


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