312C, 315C, 318C, 319C, 320C, 321C, 322C, 325C, 330C and M325C Excavators and 325C MHPU and 330C MHPU Mobile Hydraulic Power Units Engine and Pump Control – V2 – Engine and Hydraulic Pump Controller




Illustration 1	g00683978
Block Diagram Of Inputs And Outputs Of The 312C, 315C, 318C, 319C, 320C, and 322C Controller (1) Engine and pump controller (2) Fuse Box (3) Engine (4) Governor lever (5) Hydraulic Pump (6) Battery (7) Start switch (8) Speed sensor (9) Backup switch (10) Governor actuator (11) Feedback sensor (12) Monitor (13) Action alarm (14) Engine speed dial (15) Switch panel (16) Engine coolant temperature sensor (17) Hydraulic oil temperature sensor (18) Fuel level sensor (19) Alternator (20) Engine oil pressure switch (21) One touch low idle switch (22) Engine oil level switch (23) Hydraulic oil level switch (24) Water separator level switch (25) Swing pressure switch for the implement (26) Travel pressure switch (left) (27) Travel pressure switch (right) (28) Pressure switch for the straight travel pedal (29) Pump pressure sensor (drive) (30) Pump pressure sensor (idle) (31) Proportional Reducing Valve (32) Solenoid for straight travel (33) Solenoid for travel speed (34) Solenoid valve for the swing parking brake (35) Travel alarm (36) Air heater indicator (37) Switch (Clogged air filter) (38) Switch (Clogged hydraulic oil filter) (39) Engine coolant level switch (40) Pressure switch for the attachment pump (41) Pressure switch for the attachment pedal (42) Pressure switch for the attachment pedal (2) (43) Proportional reducing valve for the auxiliary hydraulics (Attachment)




Illustration 2	g00986604
Diagram Of Inputs And Outputs Of The 321C Controller (1) Engine pump controller (2) Starter switch (3) Fuse box (4) Battery (5) Engine (6) Governor lever (7) Pump (8) Speed sensor (9) Feedback sensor (10) Governor actuator (11) Backup switch (12) Action alarm (13) Engine speed dial (15) Engine coolant temperature sensor (16) Hydraulic oil temperature sensor (17) Fuel level sensor (18) Alternator (19) Engine oil pressure switch (20) One touch low idle switch (21) Engine oil level switch (22) Hydraulic oil level switch (23) Implement/swing pressure switch (24) Travel pressure switch (Right) (25) Travel pressure switch (Left) (26) Pump delivery pressure sensor (Drive) (27) Pump delivery pressure sensor (Idle) (28) Monitor (29) Proportional reducing valve for power shift pressure (30) Straight travel solenoid valve (31) Travel speed solenoid valve (32) Swing parking brake solenoid valve (33) Travel alarm (34) Air heater controller (35) Clogged air filter switch (36) Clogged hydraulic oil filter switch (37) Engine coolant level switch (38) Attachment pump pressure switch (39) Attachment pedal pressure switch (1) (40) Proportional reducing valve for flow control pressure (41) Water separator level switch (43) Attachment pedal pressure switch (2) (44) Travel alarm cancel switch (45) Travel mode switch (46) AEC switch (47) 1 pump/2 pumps change solenoid valve




Illustration 3	g00823975
Diagram Of Inputs And Outputs Of The 325C and 330C Controller (1) Engine and Pump Controller (2) Starter Switch (3) Fuse Box (4) Battery (5) Engine (7) Pump (8) Speed sensor (10) Electronic Control Module (11) Backup Switch (12) Action Alarm (13) Engine Speed Dial (14) Switch Panel (16) Hydraulic Oil Temperature Sensor (17) Fuel Level Sensor (18) Alternator (20) One- touch Low Idle (21) Engine Oil Level Switch (22) Hydraulic Oil Level Switch (23) Implement Swing Pressure Switch (24) Travel Pressure Switch (right) (25) Travel Pressure Switch (left) (26) Pump Pressure Sensor (drive) (27) Pump Pressure Sensor (idle) (28) Monitor (29) Proportional Reducing Valve (30) Straight Travel Solenoid Valve (31) Travel Speed Solenoid Valve (32) Swing Parking Brake Solenoid Valve (33) Travel Alarm (35) Clogged Air Filter Switch (36) Clogged Hydraulic Oil Filter Switch (37) Engine Coolant Level Switch (38) Work tool pressure switch (39) Attachment Pedal Pressure Switch (40) Flow Control Valve (41) Water Separator Level Switch (42) Pressure switch for attachment (43) Attachment Pedal Pressure Switch




Illustration 4	g01090443
Diagram Of Inputs And Outputs Of The M325C MH Controller (1) Engine and Pump Controller (2) Starter Switch (3) Fuse Box (4) Battery (5) Engine (7) Pump (8) Speed sensor (10) Electronic Control Module (11) Backup Switch (12) Action Alarm (13) Engine Speed Dial (14) Switch Panel (16) Hydraulic Oil Temperature Sensor (17) Fuel Level Sensor (18) Alternator (20) One-touch Low Idle (21) Engine Oil Level Switch (22) Hydraulic Oil Level Switch (23) Implement Swing Pressure Switch (26) Pump Pressure Sensor (drive) (27) Pump Pressure Sensor (idle) (28) Monitor (29) Proportional Reducing Valve (32) Swing Parking Brake Solenoid Valve (35) Clogged Air Filter Switch (36) Clogged Hydraulic Oil Filter Switch (37) Engine Coolant Level Switch (38) Work tool pressure switch (39) Attachment Pedal Pressure Switch (40) Flow Control Valve (41) Water Separator Level Switch (42) Pressure switch for attachment (43) Attachment Pedal Pressure Switch

Note: The 312C has one travel pressure switch. The 315C has one travel pressure switch. The 318C and 321C have two travel pressure switches.

Note: The Engine Control Module is on the 325C and on the 330C.

The controller is connected to the machine through two 54-pin connectors. The controller monitors the system through the inputs. Then, the controller adjustments the system through the outputs. The controller will control the hydraulic output of the pump by adjusting the power shift pressure according to the load on the machine.




Illustration 5	g00778730
Engine and Pump Controller (ECM) (44) Controller (45) Connector 1 (46) Connector 2

Table 1
Engine And Hydraulic Pump Control (Connector 1) ⁽¹⁾
No. 1	Function	Type
1	+Unswitched Battery	Power
2	Ground	Ground
4	Air Heater Relay	Solenoid Output
7	Pressure Switch for 319C, 320C, and 320C LRR	Switch Input
8	Hammer Switch for 319C, 320C, and 320C LRR	Switch Input
9	Engine Speed Dial 1	Operational Switch Input
10	Engine Speed Dial 2	Operational Switch Input
11	One-touch Low Idle Switch	Switch Input
12	Mode Switch for the AEC	Switch Input
13	+Battery	Power
14	Ground	Ground
16	Overload protection	Switch Input
17	Implement Pressure Switch for 312C and 315C	Switch Input
18	Implement Control Line 2	Output
19	Engine Speed Dial 3	Operational Switch Input
20	Engine Speed Dial 4	Operational Switch Input
21	Travel Mode Switch ⁽²⁾	Switch Input
22	Travel Alarm Switch ⁽²⁾	Switch Input
23	Key Start Switch	Switch Input
28	Implement Status 1	Output
29	Control Lever Pressure Switch 319C, 320C, 321C, and 322C	Switch Input
30	Left Travel Pressure Switch 312C and 315C ⁽²⁾	Switch Input
31	Coolant Level Switch	Switch Input
32	Hydraulic Oil Level Switch	Switch Input
33	Data Link +	Input/Output
39	Right Travel Pressure Switch ⁽²⁾	Switch Input
40	Engine Oil Level Switch	Switch Input
41	Engine Oil Pressure Switch	Switch Input
42	Clogged Air Filter Indicator	Switch Input
43	Data Link Negative	Input/Output
45	Implement Status 3	Output
46	Implement Status 4	Output
47	Water Separator Level Switch (Not in 321C)	Switch Input
48	Clogged Filter	Switch Input
53	Straight Travel Solenoid for 319C, 320C ⁽²⁾	Switch Input

^( 1 )	The connector contacts that are not listed are not used. The connector has 54 contacts.
^( 2 )	Not on M325C MH

Table 2
Engine And Hydraulic Pump Control (Connector 2) ⁽¹⁾
No.1	Function	Type
1	Straight Travel Solenoid 319C, 320C, 320C LRR, 321C, and 322C ⁽²⁾	Solenoid Output
2	Travel Speed Solenoid ⁽²⁾	Solenoid Output
2	Travel Speed Solenoid ⁽²⁾	Solenoid Output
4	Swing Brake Solenoid	Solenoid Output
4	Swing Brake Solenoid	Solenoid Output
6	Fine Swing Switch	Switch Input
7	Power Shift Solenoid	Solenoid Output
8	Pump Flow Limitation Valve Solenoid	Solenoid Output
9	Priority Control Valve	Solenoid Output
13	Travel Alarm ⁽²⁾	Output
14	Mode Indicator for the AEC ⁽²⁾	Output
15	Travel Mode Indicator ⁽²⁾	Output
16	Negative Speed Sensor	Sensor Return
17	Neutral Start Relay for 322C	Solenoid Output
19	Solenoid Return	Ground
20	Solenoid Return	Ground
21	Solenoid Return	Ground
22	Solenoid Return	Ground
23	Action Alarm	Output
24	Travel Alarm Indicator ⁽²⁾	Output
25	Engine Speed	Sensor Input
29	Coolant Temperature Sensor	Sensor Input
30	Fuel Level Sensor	Sensor Input (PWM)
35	Alternator Terminal “R”	Sensor Input (Voltage)
36	Feedback from the Governor	Sensor Input (PWM)
37	Main Pump Pressure Sensor	Sensor Input (PWM)
39	Hydraulic Oil Temperature Sensor	Sensor Input (PWM)
44	Governor Sensing	Sensor Input (Voltage)
45	Pump Delivery Pressure	Sensor Input (PWM)
46	Boom Hold	Sensor Input (PWM)
47	Backup Switch	Switch Input
52	+Battery for 319C, 320C, 320C LRR, and 322C	Power

^( 1 )	The connector contacts that are not listed are not used. The connector has 54 contacts.
^( 2 )	Not on M325C MH

The controller actuates the governor actuator and the proportional reducing valve if the speed of the engine must change. Each input and output of the controller is connected to the machine harness through two 54-pin connectors.

Input/Output

The data link is a bidirectional component. The data link allows the controller to receive information and the controller can send information. The data link is designed to allow communication between the controller and the monitor. The data link is not a visible component. The data link consists of internal control circuits and the connecting harness wiring. The controller sends information through the data link to the monitor panel. The following list contains some examples: fuel level and engine coolant temperature. The controller also receives requested information from the monitor panel.

Input

Each input will describe the status of the machine system. Two types of inputs exist: switch type and sensor type. Switches provide an open or ground to the controller. Sensors provide a signal that changes to the controller.

Switch Input (Keyswitch)

The input of the key start switch connects to the controller through connector 1 and contact 23. The key start switch will provide input information to the controller about the status of the key start switch. The input for the key start switch is +battery when the key start switch is placed in the ON position.

Switch Input (Operational Type)

Each switch input will provide information about operator requests and machine systems. The condition of the system is sent to the controller through each input. The status of each input will be grounded, open or +battery. Each input of the controller will receive information from the switches that are located in the machine systems (pressure and temperature).

Sensor Input (Frequency)

An AC signal is present for the input of the frequency sensor. The AC signal is used to represent the speed of a machine system. For example, the engine speed sensor provides an AC signal to the controller. The controller measures the frequency (Hz) of the AC signals.

Sensor Input (Alternator)

The sensor input for the alternator connects to connector contact 2-35. A square wave signal is present at this input. The signal is used to represent the speed of the alternator. The controller measures the frequency (Hz) of the square wave signal. The controller uses this information to make determinations and the controller uses this information to monitor the output of the alternator. When an abnormal condition exists, the controller will alert the operator.

Sensor Input (PWM)

The controller receives a signal that is Pulse Width Modulated. This signal will represent the condition of a machine system. For example, the controller can monitor pressure. PWM sensors provide this information. The controller measures the duty cycle of the PWM signal. This signal will represent the information that is measured. When an abnormal condition exists, the controller will alert the operator.

Sensor Input (Voltage)

Connector “2” has an input for voltage sensing. A voltage is present. This voltage will represent the condition of a machine system. For example, the level of voltage is a condition that is monitored by the controller. Analog sensors or senders provide this information. The controller measures the voltage, which represents the measured information. The controller also uses this information to monitor machine systems. The controller alerts the operator if an abnormal condition exists.

Output

The controller responds to decisions by sending electrical signals through the various outputs. The outputs will create an action or the outputs will provide information. Three status indicators inside the controller that are connected to the monitor panel are outputs of the controller. These outputs are additional to the outputs that are listed in the table for the descriptions of the connector contacts. The monitor panel shows the operating status of the engine and pump control system and diagnostic information. This action could be energizing a solenoid, sounding an alarm or activating a motor. The controller will send an output to the following components:

Governor actuator
Proportional reducing valve for the power shift pressure
Travel speed solenoid (Not on M325C MH)
Action alarm (Not on M325C MH)
Travel alarm (Not on M325C MH)
Swing parking brake solenoid
Proportional reducing valve for the tool mode
Straight travel solenoid (Not on M325C MH)