Abstract: There are electronic instrumentation assemblies in which most of the hard wired circuitry and functions are very similar for a significant number of different applications yet each assembly for a separate application is fabricated as a separate unit. Applicants system includes a single electronic circuit assembly for all such applications including a large plug-in connector, and a much smaller faceplate assembly with a mating connector unit containing software in the form of one or more PROMs plus a limited number of discrete components. An instrumentation assembly for a particular application includes the correctly programmed faceplate assembly which is plugged directly into the front panel of the electronic circuit assembly. As compared with having a separate electronic assembly for each different application, the present arrangement permits the major part of the assembly to be a single assembled unit with a single part number, configuration control, assembly and test procedure etc.

Abstract: A vibration monitoring system analyzes tachometer signals of a rotating engine to ascertain the period of rotation from which sampling pulses at predetermined intervals can be generated. Sampled accelerometer data is processed by a nonrecursive tracking digital filter to determine peak velocity or displacement of rotating engine. In a different operating phase, apparatus determines the rotational location of the peak relative to an index or reference point on the rotating engine. The magnitude and location of the peak can be signaled for subsequent correction of the imbalance. The rotational velocity is monitored so that changes in velocity during a measurement invalidate the results and cause a repetition of the measurement cycles.

Abstract: A vibration monitoring system for aircraft engines includes a nonrecursive digital filter network controlled by a data processor. Digital techniques process tachometer signals to general sampling signals at a frequency which is an integral multiple of the rotating frequency. A novel digital filter can track the rotational frequency of the rotating component and can be accurately centered upon that frequency. The digital filter includes a pair of memories, one of which stores constant coefficients and the other of which stores sampled data. The sampled data storage can accommodate the output of more than one sensor and data from each sensor can be alternatively processed.