M316c, M318c, And M322c Hydraulic Excavators: Technical Presentation

Service Training Meeting Guide 760

SESV1760 August 2002

TECHNICAL PRESENTATION

M316C, M318C, AND M322C HYDRAULIC EXCAVATORS MULTI COMBINED FUNCTION

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Monitor • M300C Monitor: 1. Monitor

The monitor informs the operator of the machine status and allows the adjustment of certain machine parameters. The monitor can be programmed to control various work tools that require different pressures and flow.

2. Alert indicator 3. Indicator lights 4. Throttle position switch indicator 5. Gauges 6. Display 7. Keypad

The monitor provides information to the operator by a gauge panel, alert indicators, throttle position switch indicator and a display panel with various screens and menus. A keypad is used to navigate the menus.

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M300C MONITOR MAIN MENU

QUICK COUPLER -LOCK -UNLOCK

PREFERENCES SELECT LANGUAGE ADJUST CLOCK ADJUST DISPLAY -CONTRAST -BRIGHTNESS (DAY) -BRIGHTNESS (NIGHT)

MACHINE INFO

MAIN MENU QUICK COUPLER PREFERENCES SELECT TOOL FILTER/FLUID HOURS SERVICE OPTIONS SERVICE OPTIONS MACHINE INFO OPERATING HOURS TOOL INDICATOR

OPERATING HOURS

MACHINE INFO -ENGINE CONTROLLER -- PART- NO -- SER-NO -- SW-VER - MACHINE CONTR -- PART-NO -- SER-NO -- SW-VER - MONITOR -- PART-NO -- SER-NO -- SW-VER - SOFT-SWITCH PANEL -- SW-VER

ENGINE CONTR MACHINE CONTR MONITOR SOFT-SWITCH PANEL TRAVEL SWING TOOL 1 TOOL 2 TOOL 3 TOOL 4 TOOL 5

SELECT TOOL NO TOOL TOOL 1 TOOL 2 TOOL 3 TOOL 4 TOOL 5 HAMMER GENERATOR

FILTER/FLUID HOURS ENGINE OIL ENGINE OIL FILTER ENGINE COOLANT FUEL/WATER SEP FUEL FILTER HYDRAULIC PILOT OIL RETURN HYD OIL FILTER HYDRAULIC OIL

TOOL INDICATOR -ENABLE -DISABLE

38 • Monitor Main menu structure

This illustration shows the Main menu structure of the monitor.

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MAIN MENU

SELECT TOOL MENU SELECT TOOL TOOL #1

SELECT TOOL NO TOOL

ACTIVE :SELECT

X:EXIT

:SELECT

X:EXIT

SELECT TOOL HAMMER

SELECT TOOL NOT CONFIGURED

:SELECT

X:EXIT

X:EXIT

42 • Select Tool menu

The Select Tool menu allows the operator to activate a predefined tool. The monitor will display all the tools that are installed on the machine: NO TOOL, five auxiliary tools for the combined function valve, and generator or hammer. The Select Tool menu is always available, even if the machine is not equipped with a combined function valve, generator valve, or hammer valve. The NO TOOL option is always available. The current tool will be displayed as ACTIVE. If a tool was setup with an invalid filename (i.e. all spaces), the monitor displays NOT CONFIGURED. A tool displayed as NOT CONFIGURED cannot be selected.

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M300C MONITOR SERVICE OPTIONS PW MENU

MAIN MENU QUICK COUPLER PREFERENCES SELECT TOOL FILTER/FLUID HOURS SERVICE OPTIONS SERVICE OPTIONS PW

SERVICE OPTIONS PW RESET SERVICE HOURS CHANGE PASSWORD ACTIVE ERROR LOGGED ERROR LOGGED EVENT SWITCH STATUS STATUS CONFIGURATION CALIBRATION TOOL ADJUSTMENT RTC COMP INTERVAL

RESET SERVICE HOURS

SWITCH STATUS

STATUS

ENGINE OIL ENGINE OIL FILTER ENGINE COOLANT FUEL/WATER SEP FUEL FILTER HYDRAULIC PILOT OIL RETURN HYD OIL FILTER HYDRAULIC OIL

ATT PEDAL FRONT ATT PEDAL BACK SWING PILOT PRESS OPER SWING BRAKE FORWARD TRAVEL PR REVERSE TRAVEL PR JOYST BUTTON ACT OPER FUEL PUMP ARMREST POSITION FORWARD TR PED LIM OPER SER BR PRES BRAKE PEDAL LIMIT CRANK W/O INJECT

AUX HYD FLOW SOL AUX HYD PRES SOL SWASH PLATE ANGLE TRANSM CLUTCH PR HYD OIL TEMP ENGINE SPEED BOOST PRESSURE FUEL TEMP COOLANT TEMP INT MANIFOLD TEMP ENGINE OIL PRESS BATTERY VOLTAGE FUEL PER HOUR FUEL TOTAL USED DESIRED ENGINE SPEED

TOOL ADJUST (TOOL 1-5) -TOOL NAME -UNI/BI DIRECT ON/OFF -BACK DIR MAX PRESS -BACK DIR MAX FLOW -FRONT DIR MAX PRESS -FRONT DIR MAX FLOW

CONFIGURATION TRAVEL ALARM BOOM ANGLE SWITCH FUEL FILLER PUMP QUICK COUPLER GENERATOR AUX HYD VALVE HAMMER AESC TIME TRAVEL PEDAL LOCK

CHANGE PASSWORD -CURRENT -NEW

CALIBRATION

45 • SERVICE OPTIONS PW menu

This illustration shows the menu structure of the SERVICE OPTIONS PW menu. The SERVICE OPTIONS PW menu is used to reset service hours, view the status of various machine components, view errors and events, adjust machine configuration, perform calibrations, and adjust the optional auxiliary hydraulic system (tool control). Once enabled, the SERVICE OPTIONS PW menu remains enabled until the engine start switch key has been turned off for two minutes.

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SERVICE OPTIONS PW MENU TOOL ADJUSTMENT MENU ADJUST TOOL TOOL NAME

TOOL SELECT TOOL #1

HAMMER______ :SELECT

X:EXIT

/

72% :+/-

:SET X:EXIT

ADJUST TOOL ONE/TWO WAY

ADJUST TOOL BACK DIR MAX PRES /

:+/-

TWO WAY

:SET X:EXIT

/

:+/-

:SET X:EXIT

54 • Tool Adjustment menu

The Tool Adjustment menu is used to set up the combined function valve. With the tool adjustment menu, the technician can program the tool's name, one-way or two-way flow, and maximum flow and pressure in the forward and backward pedal position. Settings do not take effect until the Set key has been pressed. NOTE: Although the monitor can be used to adjust the maximum flow for the combined function valve, ET is more precise because ET allows the input of tenths of a percent. The monitor requires changes to be entered as whole percentages.

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M300C MACHINE ELECTRONIC CONTROL SYSTEM INPUTS AND OUTPUTS RIGHT JOYSTICK ONE TOUCH LOW IDLE

QUICK COUPLER SOLENOID VALVE

LEFT JOYSTICK SWING BRAKE ENGAGE

MULTI FUNCTION VALVE HYDRAULIC OIL PRESSURE

SERVICE BRAKE PRESSURE SWITCH OVERLOAD WARNING SWITCH

MULTI FUNCTION VALVE HYDRAULIC OIL FLOW

LOW TRANSMISSION CLUTCH PRESSURE SENSOR

MULTI FUNCTION VALVE DIRECTION SOLENOID

BRAKE OIL ACCUMULATOR PRESSURE SWITCH SWASHPLATE ANGLE SENSOR

TRAVEL ACTIVATION SOLENOID SWING BRAKE SOLENOID PARKING BRAKE SOLENOID

TRAVEL ALARM HORN

TRAVEL SPEED SOLENOID

HYDRAULIC OIL TEMPERATURE SENSOR

HIGH PRESSURE SOLENOID

HYDRAULIC OIL CLOG SWITCH

IMPLEMENT LOCKOUT SOLENOID

ENGINE COOLANT LEVEL SWITCH

MACHINE ECM

HYDRAULIC OIL LEVEL SWITCH

SERVICE BRAKE LIGHTS

CREEPER SPEED SOLENOID OSCILLATION AXLE SOLENOID

AIR FILTER CLOG SWITCH SERVICE BRAKE PEDAL SWITCH

MAIN PUMP (PRV) SOLENOID

ARMREST POSITION SWITCH

MULTI FUNCTION VALVE PRESSURE SWITCH REVERSE

SWING PUMP (PRV) SOLENOID

TRAVEL PEDAL LIMIT SWITCH

MULTI FUNCTION VALVE PRESSURE SWITCH FORWARD

ENGINE COOLING FAN SOLENOID

BOOM ANGLE LIMIT SWITCH

FORWARD TRAVEL PRESSURE SW SWING PRESSURE SWITCH REVERSE TRAVEL PRESSURE SW STABILIZER PRESSURE SWITCH

AUX HYDRAULIC CAB RISER SOLENOID

THROTTLE POSITION SWITCH

FUEL LEVEL SENSOR BACKUP (LIMP HOME) SWITCH ENGINE ECM

CAT DATA LINK

TRAVEL LOCK MAGNET SWITCH

REFUELING PUMP RELAY QUICK COUPLER PRESSURE SWITCH IMPLEMENT LOCKOUT RELAY

SOFT SWITCHES FUEL PUMP ECM

CAT DATA LINK

MONITOR

CAT DATA LINK

CAN DATA LINK

DIAGNOSTIC TOOLS (CAT ET)

57 Machine ECM • Machine ECM inputs and outputs

The inputs and outputs of the Machine ECM are shown in this illustration. The Machine ECM communicates with the Engine ECM on the Cat Data Link and with the monitor and soft switch panel on the CAN data link. NOTE: The grouped pressure switches and grouped solenoids in the illustration share a common part number.

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Diagnostic Tools • Electronic Technician

Caterpillar Electronic Technician (ET) is used in place of the M300 Technician software program that was used on previous machines. M300 Technician is still required for servicing the former machines; however, M300 Technician will not communicate with the M300C Excavators. The M300C Excavator's ECM's use two data links to communicate. The Engine ECM, Machine ECM, the optional Product Link, and the optional Machine Security System communicate via the Cat Data Link (CDL). The monitor and soft switch panel communicate with the Engine ECM and the Machine ECM on the J1939 CAN Data Link, but do not access the CDL. During a flash download to the Machine ECM, ET normally uses the CDL. When flashing the Engine ECM, the monitor, and the soft switch panel, ET uses the J1939 CAN Data Link. If the J1939 CAN Data Link is not available, ET can flash download software to the Engine ECM via the slower CDL. Because the 7X-1700 Communication Adapter (Com Adapter I) cannot communicate on the J1939 CAN Data Link, the 1714400 Communication Adapter (Com Adapter II) should be used if the monitor or soft switch panel are to be flashed.

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83 • Machine ECM configuration screen

This illustration shows the Configuration screen for the Machine ECM of a M316C Excavator. Most of the parameters on this screen inform the Machine ECM of installed attachments. Two of the parameters are used to adjust the operation of the Automatic Engine Speed Control (AESC). The AESC Delay Time parameter adjusts the amount of time that must elapse with no hydraulic activity before the AESC becomes active. The Main Pump Swash Plate Angle Machine Operating Threshold parameter adjusts the main pump swashplate angle that must be attained before the AESC is activated. The operating threshold should be at least one degree above the pump swashplate angle at low pressure standby.

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85 • Tool setup

If the machine is equipped with the combined function valve, ET or the monitor can be used to set the flow direction, flow quantity, and pressure for up to five different tools. NOTE: The parameters for flow and pressure are listed as a percentage of flow, not as regular units. See the Testing and Adjusting manual for the procedures for correctly setting up a tool.

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M300C TOOL CONTROL

MONITOR

AUXILIARY FLOW SOLENOID AUXILIARY PRESSURE SOLENOID AUXILIARY DIRECTION SOLENOID

MACHINE ECM

CAN J1939

HAMMER SOLENOID LOCKOUT SWITCH

GENERATOR SOLENOID

GENERATOR ENABLE SWITCH

SSP

ATTACHMENT PEDAL FORWARD PRESSURE SWITCH

ATTACHMENT PEDAL REVERSE PRESSURE SWITCH

109 • Tool control

Tool Control This feature allows the following functions: configuration of tools that can be installed on the machine, choose which tool is active on the machine, and operate the active tool. There are up to seven possible installed tools, or no tool may be installed on the machine. Each of these tools will have the following parameters associated with it: -

Tool Number Tool Name Max pressure front direction Max pressure back direction Minimum flow front direction Minimum flow back direction Whether this tool is uni- or bi-directional Total Operating Hours

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The tool is operated by depressing the attachment pedal, which is monitored by two pressure switches. The electronic control system uses the input from these pressure switches to control the combined function valve. max If the back pressure switch is closed and the front pressure switch is open, the flow solenoid is set to the active tool's associated minimum flow value for the back direction or 420 mA, whichever is a greater current value. The pressure solenoid is set to the active tool's associated max pressure value for the back direction. If the machine is equipped with a generator, the generator valve is deactivated if the generator is the active tool and the generator enable switch is open. If the generator enable switch is closed, the generator solenoid will be activated. The direction solenoid is activated if the active tool is set to uni-directional. The total operating hours of this tool start to increase, based on the time it is being actuated.

max If the back pressure switch is open and the front pressure switch is closed, the flow solenoid is set to the active tool's associated minimum flow value for the front direction or 420 mA, whichever is a greater current value. The pressure solenoid is set to the active tool's associated max pressure value for the front direction. If the machine is equipped with a generator, the generator valve is deactivated if the generator is the active tool and the generator enable switch is open. If the generator enable switch is closed, the generator solenoid will be activated. The direction solenoid is activated if the active tool is set to uni-directional. The total operating hours of this tool start to increase, based on the time it is being actuated.

If the back pressure switch and the front pressure switch are both open, the flow solenoid is set to the less of the active tool's associate minimum flow values or 420 mA, if the lesser of the flow values is less than 420 mA. The pressure solenoid is set to the greater of the active tool's associated maximum pressure values. If the machine is equipped with a generator, the generator valve is deactivated if the generator is the active tool and the generator enable switch is OPEN. If the generator enable switch is closed, the generator solenoid will be activated. The direction solenoid is activated if the active tool is set to uni-directional.

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When the back pressure switch and front pressure switch are both closed a diagnostic code is generated. The flow solenoid is set to 420 mA and the pressure solenoid is set to 0 mA. If the machine is equipped with a generator, the generator valve is deactivated if the generator is the active tool and the generator enable switch is OPEN. If the generator enable switch is closed, the generator solenoid will be activated. The direction solenoid is activated if the active tool is set to uni-directional. When the Generator, Hammer or No Tool is active, the current commanded to the maximum flow solenoid is 0 Amperes. The minimum value of 420 mA only applies when one of the configurable auxiliary tools is active. When the hammer is the active tool, the Machine ECM will energize the hammer enable solenoid. When it becomes inactive, the hammer solenoid will be de-energized. NOTE: The implement lockout solenoid must be energized for the tool control to function.

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• M318C / M322C main hydraulic control valve group components: 1. Tube 2. Combined function valve 3. Bucket 4. Travel 5. Stick 6. Dozer/stabilizer drain line 7. Boom 8. Main relief valve 9. Signal limiter valve 10. Dozer/stabilizer

The standard main control valve group has five independent sections as shown: bucket control valve (3), travel control valve (4), stick control valve (5), dozer/stabilizer control valve (6), and boom control valve (7). These control valves direct main pump flow to the various implement or travel circuits. The group is equipped with the main relief valve (8) and the load sensing signal limiter valve (9). If the machine is equipped with a VA boom, the VA boom control valve is mounted on the end of the main valve body. The combined function valve (2) is mounted to the other end. A (1) is directs pump pressure to the combined function valve. This pressure is used as part of the priority circuit. An external tube is used to prevent excessive pressure loss through the valve body. The dozer/stabilizer valve has a direct connection to the hydraulic tank through hose (6).

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• M316C main valve group 1. Main relief valve 2. Signal limiter valve 3. Drift reduction valve (optional) 4. VA boom valve

The M316C uses a smaller main valve block than the M318C and M322C. The main control spools are located similarly in both valve blocks, however, the location of the main relief (1) and the signal limiter valve (2) is different.

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M300C SERIES MAIN CONTROL VALVE GROUP WITH COMBINED FUNCTION VALVE

BOOM LOWERING VALVE

QUICK COUPLER

MAIN RELIEF

DRIFT REDUCTION VALVE

FLOW SELECTOR VALVES COMBINED FUNCTION

SIGNAL LIMITER

SIGNAL DRAIN VALVE

BOOM

STICK

DOZER

TRAVEL

CONTROL SPOOL

BUCKET PRESSURE COMPENSATOR PRIORITY VALVE

FLOW CONTROL SPOOL

BACK PRESSURE VALVE

VA BOOM

BYPASS CHECK VALVE

LS DAMPER LINE FAN DRIVE SYSTEM

MAIN PUMP GROUP

161 • Hydraulic system with combined function valve

One of the proportional solenoids on the combined function valves is use to limit the pilot pressure to shift the control valve spool. This limits the maximum flow to the work tool. The other proportional solenoid is used to control the line relief settings. NOTE: The combined function valve function will be discussed in more detail later in the presentation.

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• Combined function valve components: Pump

1. Load sensing signal line 2. Stroke limiter 3. Direction solenoid 4. Line relief 5. Pressure solenoid 6. Line relief

Combined Function Valve The combined function valve can be pre-programmed for up to five work tools using either the monitor or ET. The valve uses two proportional solenoids to control the flow and pressure to the work tool. The pressure solenoid (1) is installed in the rear of the valve. The flow solenoid (8) is installed in the bottom of the valve. An additional solenoid valve (3) is used to select one-way or two-way oil flow. These solenoids are controlled through the Machine ECM. The combined function valve uses an external tube (1) to receive its load sensing signal. The external tube helps maintain the load sensing signal pressure better than internal passages.

7. Stroke limiter 8. Flow solenoid 9. Pilot line to top of spool 10.Priority valve 11.Pressure compensator

NOTE: Some service literature may refer to the valve as "Auxiliary Control Valve (Combined Function)."

Multi Combined Function P/N 1way / 2 ways solenoid flow control solenoid flow ON/OFF solenoid pressure solenoid relief valve flow control valve priority valve

Full MCV 191-2778 yes yes no yes 2 yes yes

Hammer Valve 192-3176 no no yes no 1 yes no

Generator Valve 192-3177 no no yes no 0 yes yes

Return Oil Flow Direction Control Solenoid

Port B 1 Inch SAE 6000 PSI

Port "PST" Pilot to Direction Control Valve

Test Port MB

Prio Check-Valve

Load Check Valve

Port A 1 Inch SAE 6000 PSI

Test Port Ma 01.1

Test Port MB

Stroke Limiter Pilot b 01.2 Test Port M b 01.3 Make-Up Valve B

Line Relief Valve B Pressure Control Solenoid

MP Signal Port Flow Control Valve Line Relief Valve A

Priority Valve

Pilot b 01.1

Make-Up Valve A Pilot a 01

Port L (Drain)

Multi Combined Valve Components

Flow Control Valve (spool missing)

Priority Valve

- The Flow Control Valve is simply made of a spool, a spring and a plug. It is not adjustable (unless shims would be added in the cover). The flow adjustment takes place through E.T. - The Priority Valve is made of a spool, an internal stroke limiter for the spool, a spring and a plug. It is not adjustable either (unless shims would be added in the cover).

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TO/FROM SINGLE ACTING TOOL OR DOUBLE ACTING TOOL

M300C SERIES AUXILIARY TOOL CONTROL COMBINED FUNCTION VALVE NEUTRAL

SHUT OFF BALL VALVES ONE WAY SELECTOR VALVE

FROM JOYSTICK

PRESSURE CONTROL SOLENOID

FROM PILOT MANIFOLD

COMBINED FUNCTION

SIGNAL LIMITER

BUCKET

MAIN RELIEF

SELECTOR SOLENOID VALVE

SIGNAL DRAIN VALVE

BOOM DOZER STICK TRAVEL CONTROL VALVES

LINE RELIEF AND MAKEUP VALVE

CONTROL SPOOL

PRESSURE COMPENSATOR PRIORITY VALVE

FLOW CONTROL SPOOL

LS DAMPER LINE

FLOW CONTROL SOLENOID

MAIN PUMP GROUP

181 • NEUTRAL

The combined function valve is a pressure compensated control valve featuring a flow control spool. The flow control spool maintains a controlled pressure drop across the combined function valve spool when the valve is shifted. The priority valve is used to provide flow priority to the combined function valve if multiple circuits are activated and the pump cannot satisfy all flow needs. When the combined function valve is in NEUTRAL, the priority valve is shifted up and signal oil is blocked by a check valve.

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TO/FROM SINGLE ACTING TOOL OR DOUBLE ACTING TOOL SHUTOFF BALL VALVES

COMBINED FUNCTION VALVE ONE WAY FLOW

TO/FROM SINGLE ACTING TOOL OR DOUBLE ACTING TOOL

TWO WAY FLOW

SELECTOR SOLENOID VALVE

ONE WAY SELECTOR VALVE FROM PILOT MANIFOLD

PRESSURE CONTROL SOLENOID

FROM PILOT MANIFOLD

PRESSURE CONTROL SOLENOID

COMBINED FUNCTION

LINE RELIEF AND MAKEUP VALVE

CONTROL SPOOL

PRIORITY VALVE

PRIORITY VALVE

FLOW CONTROL SPOOL

FLOW CONTROL SPOOL TO PUMP FROM PUMP

TO PUMP FROM PUMP

FROM PUMP

FROM PUMP

FLOW CONTROL SOLENOID PRESSURE SWITCH

RESOLVER

FLOW CONTROL SOLENOID FROM JOYSTICK

FROM JOYSTICK

182 • One-way flow and twoway flow

When the combined function valve is activated, pilot oil to the control spool is limited by the flow control solenoid. The maximum line pressure is controlled by the pressure control solenoid. The pressure control solenoid valve works with the two line relief valves. Some of the supply oil is directed through the line relief valve to the pressure control solenoid. This oil works with the proportional solenoid against the spring in the pressure control solenoid valve. When the spring force is exceeded, the pressure control solenoid valve shifts to drain this oil to tank. The line relief now opens to limit maximum line circuit pressure. The flow control solenoid, the pressure control solenoid, selector control solenoid are controlled by the Machine ECM. The selector control solenoid is an on and off solenoid, while the other two solenoids are proportional.

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For one-way flow, the selector solenoid is energized. The solenoid directs pilot oil to the one way selector valve. The selector valve shifts, to direct return oil from the work tool to tank and block the supply passage from the control spool. When the selector valve is de-energized, the valve blocks pilot oil to the one-way selector valve. Supply oil can be directed to either port to the work tool.

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SINGLE ACTING TOOL OR DOUBLE ACTING TOOL

M300C SERIES AUXILIARY TOOL CONTROL TWO WAY FLOW / FLOW NEEDS MET COMBINED FUNCTION WITH HIGHEST SIGNAL

ONE WAY SELECTOR VALVE

FROM JOYSTICK

SHUT OFF BALL VALVES SELECTOR SOLENOID VALVE

PRESSURE CONTROL SOLENOID

FROM PILOT MANIFOLD

COMBINED FUNCTION

SIGNAL LIMITER

LINE RELIEF AND MAKEUP VALVE

BUCKET

SIGNAL DRAIN VALVE

BOOM DOZER STICK TRAVEL CONTROL VALVES

CONTROL SPOOL PRESSURE COMPENSATOR PRIORITY VALVE

FLOW CONTROL SPOOL

LS DAMPER LINE

FLOW CONTROL SOLENOID

MAIN PUMP GROUP

FROM JOYSTICK

183 • Combined with highest signal: - Flow needs met

When the combined function valve has a higher load pressure than the other circuits and pump flow capacity had not been exceeded, the priority valve is shifted up by supply pressure. Some of the supply oil past the control spool unseats the check valve and becomes signal oil. The signal is directed to the main pump group and to all of the pressure compensators in the other implements. Some oil also flows to the flow control spool to work with the flow control valve spring to maintain the desired flow rate to the work tool.

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SINGLE ACTING TOOL OR DOUBLE ACTING TOOL SHUT OFF BALL VALVES SELECTOR SOLENOID VALVE

M300C SERIES AUXILIARY TOOL CONTROL TWO WAY FLOW / BUCKET WITH HIGHEST SIGNAL

ONE WAY SELECTOR VALVE

FROM JOYSTICK

PRESSURE CONTROL SOLENOID

FROM PILOT MANIFOLD

COMBINED FUNCTION

SIGNAL LIMITER

LINE RELIEF AND MAKEUP VALVE

BUCKET

SIGNAL DRAIN VALVE

MAIN RELIEF

BOOM DOZER STICK TRAVEL CONTROL VALVES

CONTROL SPOOL PRESSURE COMPENSATOR PRIORITY VALVE

FLOW CONTROL SPOOL

LS DAMPER LINE

FLOW CONTROL SOLENOID

MAIN PUMP GROUP

FROM JOYSTICK

184 • Bucket with highest signal: - Flow needs met - Flow needs not met

When the combined function valve has a lower load pressure than the other circuits and pump flow capacity had not been exceeded, the priority valve is shifted up by supply pressure. The signal from the bucket circuit is flows to the main pump group. The signal to the combined function valve is blocked by the check valve. The flow control spool will regulate flow to the control spool to maintain the desired flow rate based on how far the control spool is shifted. If the pump flow capacity has been exceeded and the combined function valve has a lower load pressure the other circuits, since oil takes the path of least resistance in a parallel flow system, the flow needs of the combined function valve will be satisfied, while flow to the other circuits is reduced portionally as was discussed earlier.

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SINGLE ACTING TOOL OR DOUBLE ACTING TOOL SHUT OFF BALL VALVES

M300C SERIES AUXILIARY TOOL CONTROL TWO WAY FLOW / PRIORITY FLOW COMBINED FUNCTION WITH HIGHEST SIGNAL

ONE WAY SELECTOR VALVE

FROM JOYSTICK

SELECTOR SOLENOID VALVE

PRESSURE CONTROL SOLENOID

FROM PILOT MANIFOLD

COMBINED FUNCTION

SIGNAL LIMITER

LINE RELIEF AND MAKEUP VALVE

BUCKET CONTROL SPOOL SIGNAL DRAIN VALVE

BOOM DOZER STICK TRAVEL CONTROL VALVES

PRESSURE COMPENSATOR PRIORITY VALVE

FLOW CONTROL SPOOL

FLOW CONTROL SOLENOID

LS DAMPER LINE MAIN PUMP GROUP

FROM JOYSTICK

185 • Combined with highest signal: - Flow needs not met

When the combined function valve has a higher load pressure than the other circuits and pump flow capacity had been exceeded, the priority valve moves down since the load pressure and the priority valve spring are greater than the supply pressure working below the priority valve. Some of the supply oil flows through the priority valve and becomes signal oil to control the pump. This signal oil, also is sensed at all of the pressure compensators and closes them off so no flow is available to the other implements. These valves close off due to the signal oil created by the pump supply and the pressure compensator spring are greater than the supply pressure working below each pressure compensator. By always providing priority oil flow to the combined function valve, possible damage due to cavitation to the work tool is reduced. The operator will need to reduce the desired flow demand to the other circuits in order to control more than just the combined function valve.