General Information
Sensors provide information (input) to the main display module about changing conditions such as speed and temperature. The sensor signal changes in a proportional manner in order to reflect the changing condition. The main display module shows the sensor information only on the display area. The main display module recognizes two types of sensor signals.
Frequency - The sensor produces an AC signal. The frequency (Hz) varies as the condition changes.
Pulse width modulated - The sensor produces a digital signal. The duty cycle varies as the condition changes. The frequency of this signal is constant.
Frequency Sensors
Frequency sensors produce an AC signal. The frequency (Hz) varies as the condition changes.
Speed Sensor
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| Illustration 1 | g00497032 |
Speed Sensor (1) Sensor (2) Connector | |
Speed sensor (1) is a frequency sensor. Speed sensors are used in order to measure engine RPM. The sensor generates an AC signal from the gear teeth that are passing. The signal is sent to the main display module. The main display module measures the sensor frequency (one pulse per gear tooth). The main display module then shows the engine speed.
The engine speed sensor is located on the flywheel housing. The engine speed sensor is located at the output end of the transmission housing.
Pulse Width Modulated Sensors (PWM)
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| Illustration 2 | g00304925 |
Pulse Width Modulated Signal | |
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| Illustration 3 | g00304926 |
Typical PWM Sensor Schematic | |
Pulse width modulated sensors (PWM) produce a digital signal. The duty cycle of the signal varies as the condition changes. The frequency remains constant.
Temperature Sensor
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| Illustration 4 | g00497151 |
Temperature Sensor (1) Sensor (2) Connector | |
Temperature sensor (1) reacts to the temperature of fluids. Examples of the fluids are hydraulic oil, power train oil, and engine coolant. The sensor receives operating power from the main display module (8 DCV) or from the battery (24 DCV). The sensor sends a PWM signal to the main display module, and the signal changes as the temperature changes. The main display module measures the duty cycle of the sensor signal in order to determine the fluid temperature.
Pressure Sensor
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| Illustration 5 | g00652883 |
Pressure Sensor (1) Pressure Sensor (2) Connector | |
The pressure sensor (1) reacts to the pressure of a fluid (fuel) or the pressure of air. The sensor receives operating power from the main display module (8 DCV). The sensor sends a PWM signal to the main display module, and the signal changes as the fuel pressure or the air pressure changes. The main display module measures the duty cycle of the sensor signal in order to determine the pressure.