Output condition monitor apparatus for a velocity sustaining device

A velocity-sustaining apparatus comprising:

• a detector means for detecting the velocity of a vehicle in which the apparatus is installed;
• a storage means in which a desired velocity is stored;
• an actuator means for opening or closing a throttle valve of the vehicle;
• an electronic control means for comparing the velocity detected by the detector means with the velocity stored in the storage means and providing an output signal to a driver means which provides an input signal to the actuator means in such a way that the difference between the detected velocity and the stored velocity is reduced down to zero;
• a comparator means for comparing the output signal from the electronic control means with the input signal to the actuator means;
• a monitor means which stops the operation of the electronic control means when said output signal and said input signal do not agree;
• wherein said monitor means has a first time limit means and provides an output signal which stops the operation of the electronic control means when the time limit means indicates that disagreement between said output signal from said electronic control means and said input signal persists for a first period of time;
• wherein said monitor means has a second time limit means which inhibits the electronic control means from resuming its normal operation when said output signal from said monitor means persists for a second period of time;
• and
• wherein the first period of time for which said first time limit means is set is longer than the second period of time for which said second time limit means is set.