Importance

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Abstract

A method and apparatus for concentrating diverse input signals indicative of the state or magnitude of a variety of functions and conditions of an engine-driven watercraft is disclosed. A power regulation portion includes a feedback resistor configured to form a hysteresis loop to prevent operation in a linear region when an over voltage condition exists, thus protecting the circuitry from excessive power dissipation. The apparatus also includes a reverse voltage protection circuit including a diode and a polyswitch that protects downstream circuits from application of reverse polarity power. An inventive method for determining the speed of the watercraft, using a measured pressure, and which includes a calculated component designed to account for the effects of the friction as in a pitot tube is disclosed. An input is obtained from a user-actuated switch, such input being used to vary an adjustment factor, which in turn varies the watercraft speed determination using the inventive speed method. A method of determining a rotational speed of a rotating component of an engine in the engine-driven watercraft is also disclosed. The speed determining method includes the steps of defining a sampling time, counting the number of pulses of a tachometer signal having pulses for the sampling time, and determining an average time interval per pulse. The average time interval per pulse parameter is then used to calculate a rotational speed of the engine.

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First Claim