WINCH AR-TOWING 7T3284 - Caterpillar

Illustration 1 g03509980
Machine electronic control module (ECM) outputs (1) Machine ECM (2) Differential left steering solenoid (3) Differential right steering solenoid (4) ECM 2The electronic control module (ECM) will use output circuits to send electrical control signals to the output components. The output signals can create an action or the output signals can provide information to the ECM. The ECM will use different types of output signals to control the system components. The electrical signal types are the following types:
PWM proportional driver outputs
ON/OFF driver outputs
Sinking driver outputs
Sensor power supply outputs
Data link outputsThe ECM monitors the circuits of the output components. If the ECM determines that an abnormal condition exists in one of the circuits, the ECM will log a diagnostic code for the involved component.Steering Electrical Outputs
Illustration 2 g03509982
Steering valve solenoidsThe basic components of the differential steering system include the following items: a planetary and brake unit, a steering differential and brake unit, a hydraulic steering pump, a hydraulic steering motor, and the steering controls. The units transfer power from the bevel gear to the final drives in varying proportions. The input is based on the operator input from the steering control lever. Input from the steering control lever signals the steering pump to send oil to the steering motor. The steering motor acts on the steering differential and brake unit in order to vary the power to each final drive. The solenoid valves for the left steering pump and the right steering pump are outputs of the machine ECM. The machine ECM uses these solenoid valves to steer the machine. The solenoids control the direction and the amount of the pump oil displacement. Each solenoid has a connector with two contacts.One contact receives a signal from the corresponding J1-67 or J1-68 connector contact of the ECM. The other contact of each solenoid is connected to the return circuit of the solenoid at J1-54.The solenoids are the proportional type. The ECM uses a pulse width modulated signal (PWM) in order to vary the current to the solenoid. The distance of travel of the plunger is proportional to the electrical current that is sent by the ECM. The position of the plunger controls the amount and direction of the pump displacement. A decrease in electrical current to any one solenoid causes a decrease in pump displacement in that direction.The operator selects the amount of pump displacement by pulling or pushing the direction/speed control lever. As the direction/speed control lever is pulled toward the operator, the solenoid for the right steer is activated during right forward turns and left reverse turns. Similarly, as the direction/speed control lever is pushed away from the operator, the solenoid for the left steer is activated during left forward turns and right reverse turns.