CONTROL AR- 4605618 - Caterpillar

Hystat Joystick
Illustration 1 g00786189
The electrohydraulic control system has a two axis joystick as the operator interface. The joystick is used in order to supply direction and steering commands. The longitudinal displacement of the joystick will control the forward and the reverse direction of the machine. The lateral displacement of the joystick will provide the steering control. The joystick steering sensor (1) provides a 500 Hz PWM signal and the joystick F/N/R sensor (2) provides a 500 Hz PWM signal. The signal is proportional to the joystick sensor position for each axis. The range of the sensor in the longitudinal axis is nominal at 30% at the full forward position to 70% at the full reverse position. The range of the sensor in the lateral axis is nominal at 25% at the full left position to 75% at the full right position.Speed Sensor (Engine)
Illustration 2 g00288428
Speed Sensor (Engine)The engine speed sensor is an input to the ECM. The sensor tells the ECM the speed of the engine. The engine sensor produces a signal. The frequency of the sensor signal will vary as the engine speed changes. The signal frequency is one pulse per tooth on the flywheel. The ECM uses information from the engine speed sensor and the position sensor for the decelerator pedal in order to perform the underspeed function. Speed Sensors
Speed Sensor (Left Track)Speed Sensor (Right Track)
Illustration 3 g00787531
A track speed sensor is integrated into the output stage of the hydrostatic drive motors. The sensor provides two square wave signals that are 90 degrees out-of-phase and the frequency remains proportional to motor speed while the amplitude remains constant. These signals shall be used to calculate both track speed and direction of rotation. The sensors require a regulated 8 volt power supply. For the D4G and D5G machines, the motor speed pickup gear has 67 teeth.For the D3G machines, the motor speed pickup gear has 58 teeth.Pedal Position Sensors
Decelerator PedalService Brake Pedal
Illustration 4 g00904530
Position Sensor (Decelerator Pedal)Position Sensor (Service Brake Pedal)The position sensors inform