349E, 349F and 352F Excavators and 349E MHPU Mobile Hydraulic Power Unit Tool Control System Caterpillar

Introduction

The proportional reducing valves for limiting pilot pressure for the Boom DOWN and Stick IN functions are located underneath the main control valve. These valves are used along with the Combined Function - Electric Control tool control system to increase the controllability of the work tool.

The proportional reducing valves limit pilot oil pressure from the joysticks to the control valves in the main control valve. These valves are controlled by a PWM signal from by the machine ECM in accordance to operator and pressure sensor input.

Required Tools

Illustration 1	g01623868
Tooling group "B" 198-4240 Digital Pressure Indicator Gp

Machine Preparation

1. The following procedures must be completed before performing the calibration.
   • Set the pilot pressure to the specifications in Testing and Adjusting, "Relief Valve (Pilot) - Test and Adjust" for the machine.

2. Position the machine on level ground. Ensure that there is enough clearance for the implements to Boom DOWN and Stick IN.

   Note: For Boom DOWN calibration, position the front implements with the work tool on the ground.

3. Stop the engine.

4. Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "System Pressure - Release".

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Illustration 2	g03626279
Front view of main control valve (typical example) (1) Pressure tap (Boom DOWN) (2) Pressure tap (Stick IN) (3) Proportional reducing valves (pilot pressure limit)

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Illustration 3	g03626421
Pilot pressure limit valves located below main control valve (typical example) (1) Pressure tap (Boom DOWN) (2) Pressure tap (Stick IN) (3) Proportional reducing valves (pilot pressure limit)

5. Connect a 3447 kPa (500 psi) pressure sensor to the pressure tap for attachment valves.

6. Start the engine.

7. Place the machine controls at the following settings: engine speed dial "10" and AEC switch OFF. Refer to Testing and Adjusting, "Engine Performance - Test (Engine Speed)" for engine rpm settings.

8. Increase the hydraulic oil temperature to 50° ± 10°C (122° ± 18°F).

Calibration Procedure

Note: This procedure is typical for both proportional reducing valves for Boom DOWN and Stick IN functions.

1. Select a work tool for the tool system. Refer to Testing and Adjusting, "Work Tool - Select" for the Tool Control System.

Monitor Procedure

The following procedure will allow the user to calibrate the pilot pressure limit solenoid valves using the monitor.

1. Enter the service mode. Input the password "9992".

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Illustration 4	g02276317

2. Select "Pilot Pressure Limit Solenoid" from the "Calibrations" menu.

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Illustration 5	g02276321

3. Select the pilot pressure limit solenoid valve to calibrate from the "Pilot Press Limit Solenoid" menu. The options for "Boom Cyl Retract" and "Stick Cyl Extend" will calibrate the pilot pressure limit valves for this tool control system.

4. Press the OK key in order to start the calibration. The engine RPM will automatically increase to the equivalence of engine speed dial 10 for "Stick Cyl Extend". The engine RPM will automatically decrease to the equivalence of engine speed dial 1 for "Boom Cyl Retract".

5. Confirm the notes on the monitor display. Set up the test conditions in accordance with the instructions. Press the OK key.

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Illustration 6	g02276324

Note: Control input for "Boom Cyl Retract" is to Boom DOWN. Control input for "Stick Cyl Extend" is to Stick IN.

6. Hold the control input in the FULL ON position.

7. Use the arrows to adjust the pressure until the pressure reading is at 500 ± 50 kPa (73 ± 7 psi). Press the device for activation 3 times and release the device for activation 3 times for each adjustment.

8. Press the OK key when the pressure reading holds steady at 500 ± 50 kPa (73 ± 7 psi) and no more adjustment is required.

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Illustration 7	g02276318

Note: Control input for "Boom Cyl Retract" is to Boom DOWN. Control input for "Stick Cyl Extend" is to Stick IN.

9. Hold the control input in the FULL ON position.

10. Use the arrows to adjust the pressure until the pressure reading is at 2500 ± 50 kPa (363 ± 7 psi). Press the device for activation 3 times and release the device for activation 3 times for each adjustment.

11. Press the OK key when the pressure reading holds steady at 2500 ± 50 kPa (363 ± 7 psi) and no more adjustment is required.

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Illustration 8	g02276319

12. If calibration was successful and no errors occurred, the display will indicate that the calibration is complete.

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Illustration 9	g02276320

13. The "Error" screen will be displayed on the monitor if an error occurs. The process of calibration will not be saved and the process must be restarted.

Cat Electronic Technician Procedure

The following procedure will allow the user to calibrate the pilot pressure limit solenoid valves using the Cat Electronic Technician.

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Illustration 10	g02713701
Diagnostic connector for Cat Electronic Technician

1. Connect the Cat Electronic Technician to the diagnostic connector located behind the seat on the left side of the cab.

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Illustration 11	g02713758

2. Start Cat Electronic Technician.

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Illustration 12	g02713761

3. Select the ECM for "Machine Control".

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Illustration 13	g02723808

4. Select "Calibrations" from the "Service"menu.

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Illustration 14	g02724584

5. Highlight "PRV - Solenoid Pressure Calibrations" and click on the "Start" button in the lower left corner of the screen.

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Illustration 15	g02724585

6. Select the pilot pressure limit valves to calibrate and press the "Begin" button.

   Note: The pilot pressure limit solenoid valves, "Boom Cylinder Retract Limit Solenoid Calibration" and "Stick Cylinder Extend Pilot Pressure Limit Solenoid Cal", are used only on the "Combined Function - Electric Control" tool control system.

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Illustration 16	g02724586

7. Follow the instructions on the screen. Press "Next" button to continue through to the next step.

Note: Control input for "Boom Cyl Retract" is to Boom DOWN. Control input for "Stick Cyl Extend" is to Stick IN.

8. Hold the control input in the FULL ON position.

9. Use the arrows to adjust the pressure until the pressure reading is at 500 ± 50 kPa (73 ± 7 psi). Press the device for activation 3 times and release the device for activation 3 times for each adjustment.

10. Press the "Next" button when the pressure reading holds steady at 500 ± 50 kPa (73 ± 7 psi) and no more adjustment is required.

Note: Control input for "Boom Cyl Retract" is to Boom DOWN. Control input for "Stick Cyl Extend" is to Stick IN.

11. Hold the control input in the FULL ON position.

12. Use the arrows to adjust the pressure until the pressure reading is at 2500 ± 50 kPa (363 ± 7 psi). Press the device for activation 3 times and release the device for activation 3 times for each adjustment.

13. Press the "Next" button when the pressure reading holds steady at 2500 ± 50 kPa (363 ± 7 psi) and no more adjustment is required.

14. If the calibration was successful and no errors occurred, the display will indicate that the calibration is complete. Press the "Finish" button to exit or move on to the next calibration.

15. If the calibration failed, the calibration is not saved. Press the "Restart" button to try the calibration again or press the "Finish" button to exit or move on to the next calibration.