Abstract: The present invention is a component monitoring system which includes all sensor and plant component monitoring at distributed plant locations close to the sensors which are the source of the signals to be analyzed. Minimally preconditioned analog sensor signals are multiplexed and further conditioned by a sensor signal preprocessor that adjusts the gain and filters the sensor signals before being applied to an analog-to-digital converter controlled by a data acquisition computer. The analog sensor signals are converted into digital samples and stored in a data memory of a digital signal processor using a direct memory access technique. The data acquisition computer also controls the selection of sensors, gain, etc., based on commands from a controller. The digital signal processor, once sufficient sensor data has been collected, performs appropriate processing using known digital signal processing techniques.

Abstract: The present invention includes a keyboard encoder which encodes a key selected by an operator. The encoder is isolated from a bi-directional bus by an isolation circuit. When a key has been selected a key code is made available for reading by a separate CPU. The separate CPU enables transfer of the key code from the encoder to the bi-directional bus and then reads the key code. The separate CPU acknowledges receipt of the key code and provides feedback to keyboard operator by sending a bank and light selection code to the keyboard over the bi-directional interface bus, after the isolation circuit has been reactivated and after a function, to be performed by the separate CPU and specified by the key code, has been started. The isolation circuit prevents the key code and the bank and light selection code from becoming intermixed on the bi-directional bus. The bank select code is used to select a bank of light code decoders which activate a light corresponding to the light code.