Snap-on Tools Corporation

Dennis W Weidenbenner

Craig F Govekar

Michael C Putrow

Gary D Jonker

Robert O Quinn

Leonard J Wisneski, Jr

Gordon Lindhard

A microprocessor controlled digital engine analyzer receives analog input signals from an engine being analyzed, engine parameter data entered via a keyboard, and function data, selecting one of several operating modes for the analyzer and which information is to be displayed, entered via the keyboard, and displays on a CRT screen the selected information such as cylinder firing order, RPM, Dwell, KV and DC volts, alphanumerically, information such as primary and secondary ignition and voltage, alternator and fuel injector information through the use of continuous waveform patterns, and additional information pertaining to Dwell, KV and Cylinder Shorting through the use of bar graphs. The waveform pattern data derived from the analog input signals is stored in a dual bank waveform memory and read out for display on the CRT screen under hardware control, and address data representing alphanumeric data and screen formats for the various operating modes to be displayed is stored in a dual bank display memory for application to a character generator, a bank switching arrangement being used for both the waveform memory and the display memory to enable the banks of each memory to be alternately written to and read from. A main microprocessor receives and processes analog input signals, other than the waveform pattern signals, and a display microprocessor receives numerical data from the main microprocessor and causes display of the numerical data on the CRT screen.

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Union Grove, WI, United States of America

Dennis W Weidenbenner