IFDs: Intermittent Fault Detectors (developed & manufactured by Universal Synaptics Corporation)
Ncompass / Ncompass-Voyager: Enhanced IFD Intermittent Fault Detectors (adds Scanning Continuity, Z-Sweep, Log-Scope, Auto-Map & more)
IFDIS: Intermittent Fault Detection and Isolation System (multiple IFD / Ncompass modules, racked and combined with environmental stimulus and custom Interface Test Adaptation (ITA)). Up to 16,384 simultaneous test points.
NFF: No Fault Found / No Faults Found / No Problem Found (NPF) / No Trouble Found (NTF) / No Defect Found (NDF) / Retest OK (RTOK) / Etc.
Electrical intermittence is a "temporary" deviation from the nominal operating condition of a circuit or device. Common root causes of intermittence are the component interconnecting devices such as solder joints, connectors, cables / wires, crimps, splices, circuit traces, via's, wire wraps, relays, circuit breakers, etc. There are typically several thousand of these devices in a modern avionics system. Other than through damage, these devices tend to wear or corrode gradually, over long periods, and thereby fail intermittently long before eventually failing permanently or "hard / semi-hard". It takes only one location becoming intermittent to render an entire system unreliable. Fixing an intermittent root cause is relatively easy. Detecting and isolating the intermittent is the challenge. The severity (amplitude and duration) of Intermittents generally gets worse over time. The further up this degradation curve that you can detect and eliminate these type problems (prognostics) the better your Mean Time Before Failure (MTBF) becomes. Inter-connection reliability is critical to the dependable performance of nearly all modern electronic systems. Comprehensive intermittence testing specifications are therefore necessary if you want to ensure this reliable performance.
Nanosecond intermittency can result in a loss of information. This loss, often leads to system failures, and typically occurs in the extremes of the operating environment. The speed and performance of today’s avionics demands that industry test-specifications for testing intermittency and reliability be performed at these increased levels also! To test otherwise, only ASSURES that intermittent defects WILL ESCAPE detection and remain in the system to further hamper and hazard the crew and the mission. Inadequate testing specifications for intermittency ARE a primary reason that No Fault Found (NFF) is so prevalent and endemic in the avionics and electronics industry today. Test equipment typically employed for measuring intermittents or dis-continuities (like scanning continuity testers) or any other single-line-at-a-time methodology (Reflectometry, Digital, DVM, Etc.) are simply incapable of achieving the necessary performance levels to detect the extremely low-level intermittence causing NFF.
Intermittence occurs RANDOMLY in TIME, AMPLITUDE and DURATION, and RARELY REPEATS with the same parameters. It might repeat only once or it might not repeat at all during a given test period. Therefore, the hope of detection revolves around test equipments SENSITIVITY to the problem (fast testing speeds with high sensitivity to low-level impedance changes) and the PROBABILITY that you will even be testing the correct circuit at the exact microsecond that a nanosecond event might occur.
For intermittence test coverage and testing-effectiveness calculation formulas and instructions, please see the technical paper found at the following link... The Right Stuff for Aging, Intermittence and No Fault Found.
In contrast, the IFD / IFDIS / Ncompass monitor each and every circuit individually (all-lines-all-the-time) in a SIMULTANEOUS and CONTINUOUS manner. By monitoring every single circuit at the same time in parallel, those random, intermittent events are not missed. The IFD / IFDIS / Ncompass were specifically designed from the ground up to overcome all of the conventional ATE and WTS / AWTS technologies intermittence testing limitations. The IFD / IFDIS / Ncompass was conceived to detect, identify and isolate the low-level intermittence causing NFF through the use of a patented analog, hardware neural network, which allows it super sensitive circuitry to monitor all of the test lines, all the time, whereas scanning continuity test sets are designed to only check one wire or circuit at a time.
You can’t detect an intermittent event until it occurs, and then you might have limited opportunities to catch it on the specific circuit when it does. Trying to measure fractions of a milliohm, scanning one circuit at a time, is completely ineffective for intermittent failure modes with or without environmental stimulus.
Prior to the development of the IFD’s, Intermittent Fault Detection technology, testing all lines, at the same time, simultaneously and continuously, was not really possible to any efficient degree using conventional test technology. The only way to comprehensively detect the low-level intermittence causing No Fault Found (NFF) is to test all of the lines, at the same time, simultaneously and continuously. The sensing technology also has to be super-sensitive on each of the individual lines to pick up the developing intermittent problems. Having significant experience and interest in the science of Artificial Intelligence (AI), our company’s founders felt the most analogous solution to this testing dilemma would be to mimic the parallel distributed processing operation found in the operation of the human brain and sensors of the body’s nervous system. The resulting IFD and its current derivatives, the Ncompass and IFDIS all share a common intermittence testing architecture that, in its basic form, comprises a Hardware Neural Network.