Abstract: An online valve monitoring system senses operational characteristics of a valve and provides a diagnosis of aberrations in the characteristics. Sensors, coupled to a valve, supply sensor signals as output to a data acquisition system to be transmitted to a remote location. An I/O processor at the remote location receives the sensor signals and a diagnostic processor extracts characteristic features from the sensor signals as deviations from baseline data for the valve. An expert system applies a rule base to the characteristic features individually or in combination to diagnose the causes of the deviations. Use of multiple sensors increases the confidence of the diagnosis which can be immediately communicated to an operator and used for scheduling maintenance of the valve. Use of this diagnosis and the trend line of historical data permits scheduling of preventive maintenance.

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.