HARNESS AS-CAB 3705378 - Caterpillar

When the device for activation listed in Table 3 is pressed, the machine ECM sends a modulated signal to proportional reducing valve (34) and proportional reducing valve (35). Proportional reducing valve (34) allows pilot oil to flow to attachment control valve (2). Proportional reducing valve (35) allows pilot oil to flow to attachment control valve (6). The pilot oil shifts attachment control valve (2) and attachment control valve (6 ), allowing high-pressure oil from the drive pump and the idler pump to combine and flow to the work tool.When abnormally high pressure occurs in the line to work tool, variable relief solenoid valve (7) opens the parameter set pressure. This opening will allow the high-pressure oil into the return system and back to the hydraulic tank. The pressure setting of variable relief solenoid valve (7) are adjustable through the monitor.Oil returning from the work tool flows into the return system through variable relief solenoid valve (9) and back to the hydraulic tank.During the operation of the work tool, the oil flow for the drive pump is controlled by flow limit valve (18) and the machine ECM. The oil flow for the idler pump is controlled by flow limit valve (17) and the machine ECM.Two-Way Flow from Two Pumps
Two-way flow from two pumps can be achieved by selecting a work tool that requires two-way flow from two pumps. The work tool can be selected through the monitor or by the work tool select switch. A typical example is a shear that receives oil from two pumps. When this work tool is selected, variable relief solenoid valve (9) is changed to a previously set pressure to turn into two-way flow mode.ReferenceRefer to Testing and Adjusting, "Work Tool Parameter - Program" for the tool control system to change the settings for work tool operation.ReferenceRefer to Testing and Adjusting, "Combined Function - Electric Control: Default Value of Work Tool Parameters" for the Tool Control System to reference the factory settings.
Table 4
Operation Lever List    
Control     Extension     Retraction    
Right Joystick Thumb Wheel     Push Forward     Push Backward    
Electric Foot Pedal     Push Forward     Push Backward    
Illustration 8 g03891751
Two-Way Flow from Two Pumps (1) Tool line relief valves (2) Attachment control valve (idler pump) (6) Attachment control valve (drive pump) (7) Variable relief solenoid valve (9) Variable relief solenoid valve (17) Proportional reducing valve (Flow limit 2) (18) Proportional reducing valve (Flow limit 1) (21) Pilot pump (22) Drive pump (23) Idler pump (34) Proportional reducing valve (A2 extend) (35) Proportional reducing valve (A1 extend)When the device for activation listed in Table 4 is pushed forward, proportional reducing valve (34) and proportional reducing valve (35) receives a modulated signal from the machine ECM. Proportional reducing valve (34) allows pilot oil to flow to attachment control valve (2). Proportional reducing valve (35) allows pilot oil to flow to attachment control valve (6). The pilot oil shifts attachment control valve (2) and attachment control valve (6), allowing high-pressure