Patent ID: 8600642

Claim:
A hub unit adapted for use in a monitoring system for monitoring engine performance parameters of a gas turbine engine while operating, wherein the hub unit is mounted on the engine or on a test stand supporting the engine and is subjected to a temperature in a range of in excess of 125° C. up to at least 200° C., the monitoring system comprising sensors mounted on the engine for sensing the engine performance parameters and generating analog sensor outputs, the hub unit comprising: a housing; at least one signal conditioning circuit board within the housing and adapted to receive the analog sensor outputs from the sensors; a control circuit board within the housing, connected to the signal conditioning circuit board, and adapted to produce digital data corresponding to the analog sensor outputs, wherein the control circuit board and the signal conditioning circuit board comprise electrical circuit components that define an analog signal processing path and have accuracy and precision characteristics that drift in response to component aging and to changes in the temperature to which the hub unit is subjected; means on the signal conditioning circuit board for multiplexing a plurality of the analog sensor outputs generated by the sensors to produce a plurality of individual multiplexed analog outputs, each of at least first and second sets of the individual multiplexed analog outputs being produced from corresponding first and second sets of the analog sensor outputs generated by corresponding first and second banks of the sensors; at least two amplifiers each with adjustable gain for scaling one of the first and second sets of the analog sensor outputs of the corresponding first and second sets of the individual multiplexed analog outputs to produce corresponding first and second sets of individual conditioned multiplexed analog outputs from which the corresponding digital data are produced, the amplifier and the adjustable gain thereof being controlled by the control circuit board; means for performing a continuous calibration scheme by periodically applying a reference voltage and a zero voltage to the signal conditioning circuit board to determine and remove errors in the analog signal processing path resulting from the drifts of the electrical circuit components of the control circuit board and the signal conditioning circuit board; and means on the signal conditioning circuit board for interleaving at least the first and second sets of the individual conditioned multiplexed analog outputs and reducing settling time between the first and second sets of the analog sensor outputs to improve throughput to the control circuit board.