Abstract: A monitoring or control system includes a plurality of senders or sensors which are coupled to a central control unit by separate cables. The control unit includes a microprocessor which executes an intermittent fault detection algorithm while an operator manually flexes each cable in turn. When a cable with a fault is manipulated the algorithm responds by energizing a horn.

Abstract: A fluid filter monitoring system includes a filter relief valve movable in response to a pressure buildup caused by filter clogging to sequentially actuate a pair of pressure-operated switches. A temperature sensor senses the temperature of fluid in the hydraulic system. A control unit, including a microprocessor, controls the energization of a plurality of indicators, depending upon the status of the temperature sensor, the pressure-operated switches and the duration of actuation of the switches.

Abstract: A vehicle, such as an agricultural tractor, includes a hydraulic assist-type transmission with fluid control and lubricating circuits. A monitoring system senses the fluid pressure in the lubricating circuit, the hydraulic fluid temperature and the engine speed. The sensed pressure is compared to a temperature and engine speed-compensated alarm value. Alarm signals are generated when the sensed pressure is continuously below the alarm value for a certain period. The alarm is disabled when the engine speed falls below a non-zero threshold level.

Abstract: An engine oil pressure monitor includes an engine oil pressure sensor and an engine speed sensor. A plurality of pressure alarm values are generated to correspond to designated distinct ranges of engine speed. One of the alarm values is selected according to which engine speed range contains the sensed engine speed. An alarm signal is generated when the sensed pressure falls below the alarm value. The alarm is disabled when the engine speed falls below a minimum non-zero engine speed and is disabled unless the pressure failure condition persists for at least a predetermined time period.

Abstract: An agricultural vehicle, such as a tractor, includes an engine and a hydraulic assist-type transmission coupled together by a clutch. A monitor includes sensors for sensing engine speed, clutch temperature and transmission temperature. Warning signals are generated if the clutch temperature is continuously and at least a certain amount hotter than the transmission temperature for a certain time period. The warning signals are disabled if the engine speed is less than a threshold and for a certain time interval after the engine speed exceeds the threshold.