Method of monitoring engine performance parameters of a gas turbine engine

A method of monitoring engine performance parameters of a gas turbine engine operating on a stationary test stand, the method comprising:

• mounting sensors on the engine to sense the engine performance parameters and generate analog sensor outputs;
• conditioning the analog sensor outputs to produce corresponding digital data, the conditioning step being performed with a control circuit board and at least one signal conditioning circuit board of at least one hub unit that is mounted sufficiently close to the engine and the test stand so as to be subjected to a first temperature in excess of 125° C., the control circuit board and the signal conditioning circuit board comprising 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 first temperature to which the hub unit is subjected;
• receiving the digital data from the hub unit with a collector unit mounted sufficiently close to the engine and the test stand so as to be subjected to a second temperature in excess of 55° C. but less than 125° C., the collector unit comprising a power supply, an enclosure containing a system voltage reference device and means for maintaining the system voltage reference device at a regulated temperature;
• operating the power supply to supply electrical power to the collector unit, the control circuit board and the signal conditioning circuit board of the hub unit, and the sensors;
• operating the system voltage reference device to produce a reference voltage;
• performing a continuous calibration scheme by periodically applying the reference voltage and a zero voltage to the signal conditioning circuit board to determine and remove errors in the analog sensor outputs resulting from the drifts of the electrical circuit components of the control circuit board and the signal conditioning circuit board;
• multiplexing a plurality of the analog sensor outputs generated by the sensors to produce an individual multiplexed analog output;
• scaling the analog sensor outputs of the individual multiplexed analog output with at least one amplifier with adjustable gain to produce an individual conditioned multiplexed analog output from which the corresponding digital data are produced;
• controlling the amplifier and the adjustable gain thereof with the control circuit board;
• and
• receiving the digital data from the collector unit with a distributor computer unit located sufficiently remote from the test stand so as to be subjected to a third temperature of less than 55° C., the distributor computer unit processing the digital data to assess the engine performance parameters of the engine.