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| Illustration 1 | g03664858 |
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| Illustration 2 | g03664876 |
The optional ride control system dampens the ride during machine travel. The Series 990K ride control valve (13) has been redesigned and is now equipped with an activation solenoid (34) and a balance solenoid (35). The Implement ECM (47) controls both solenoids. The ride control valve is located near the articulation hitch. The ride control activation solenoid controls the oil flow between the head end of the lift cylinders, ride control accumulators (36), and the oil flow between the rod end of the lift cylinders and the tank.
The balance solenoid controls the pressure in the ride control accumulators acting on the balance valve spool. The balance valve uses the accumulator pressure and the pressure in the head end of the lift cylinders to equalize the pressure when the ride control activation valve is not activated. Equalizing the pressure helps to maintain bucket position when the ride control system is activated. The pressure is equalized instantaneously before the ride control system activates.
When the ride control button in the cab is pressed, a signal is sent to the Implement ECM (47), which enables the ride control AUTO mode. The ride control system will automatically turn ON when the ground speed exceeds
The ride control activation speeds can be configured using the monitoring system information display or through Cat ET. The factory default speed is
If the ride control switch is pressed and held for 2 seconds and the parking brake is engaged, the ride control system is in SERVICE mode and ride control is active. The SERVICE mode is used only for machine servicing.
Once the ride control is in the SERVICE mode, placing the machine in the FLOAT position will purge pressure off the system.
Implement Hydraulic System - Ride Control Activated
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| Illustration 3 | g03665070 |
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(1) Implement pump
(12) Implement main control valve (13) Ride control valve (16) Lift cylinder (18) Lift cylinder (19) Lift cylinder H-E pressure sensor (20) Lift cylinder R-E pressure sensor (34) Ride control activation solenoid (35) Ride control balance solenoid (36) Ride control accumulators (57) Key Switch (60) Implement ECM | |
When the bucket is raised off the ground, there is pressure in the head end of the lift cylinders (16) and (18), which acts on the right end of the balance valve (62) in the ride control valve (13). During normal ride control operation, the balance solenoid (35) is energized by the Implement ECM (60), which directs oil from the left end of the balance valve to the tank. The balance valve shifts to the left. Oil from the implement pump (1) flows through the check valve and the balance valve to the ride control accumulators (36), charging the accumulators. When the accumulators are fully charged, accumulator oil pressure closes the check valve.
When the ride control activation speed is reached, the balance solenoid is de-energized momentarily, which directs accumulator oil to the left end of the balance valve. The balance valve moves to the right to balance the pressure in the accumulators with the pressure in the head end of the lift cylinders.
When the Implement ECM (60) energizes the activation solenoid (34), the activation solenoid directs accumulator oil to the left end of the ride control main spool (61). The main spool shifts to the right and the head end of the lift cylinders are connected with the ride control accumulators, and the rod end of the lift cylinders are connected to the tank. A floating piston in the accumulators separates the oil from the nitrogen gas. Since nitrogen gas is compressible, the gas functions as a spring.
The Cat Data Link is an input/output of the ECM. The data link uses the connector for the service port in order to communicate with the Caterpillar Electronic Technician. A data link connection is provided for the product link.
Note: The control for the product link provides a global positioning system for the machine.
The data link is bidirectional. The bidirectional link allows the ECM to input information and output information. The data link consists of the following parts: internal ECM circuits, the related harness wiring, the service tool connector and the connector for the product link. The Cat.
- The ECM receives commands from the Cat ET in order to change the operating modes. The Cat ET will read the service codes that are stored in the memory of the ECM. The Cat ET will clear the service codes that are stored in the memory of the ECM.
- The ECM sends the input and the output information to the Caterpillar ET.
Note: An electronic control module that uses the Cat Data Link will have a module identifier. The MID for the Machine Electronic Control Module is 039.
A data link is required for communication with the service tool (Cat ET) and the electronic control modules as well as instrument clusters and other devices that use this communications protocol. The data link is not used in order to broadcast any diagnostic information.
On most Cat machine models, there is more than one CAN system. These CAN systems are used to conduct high speed operational data transfer between control modules. Some components also now use the CAN data link to send input signals to the ECM.