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SANY Crawler Hydraulic Excavator SY215CLC (CUMMINS QSB6.7 engine). Shop Manual - page 17

Structure and Function

SY215C

4-172

4.9

Electrical Control System

4.9.1

Control function

Engine/Pump composite control function

Pump control function

Valve control function

Duo travel speed control

Electronic control system

Auto-deceleration/acceleration control

Engine oil under-pressure alarm

Engine preheating/overheating alarm

Engine speed calibration function

Self-diagnosis function

★

For detailed information about self-diagnosis function, see "Troubleshooting"

Structure and Function

SY215C

4-173

4.9.2

Machine control system diagram

ZX215-1002184

14
15

Battery

Battery relay

Start switch

Preheating signal

Power ON signal

Starting signal

Monitor panel

Signal monitor info

Network signal

Working mode signal
Travel spd select signal
Auto-deceleration signal
Signal monitor info

Fuse

Swing priority signal

Fuel control dial

R. travel signal

L. travel signal

Boom UP signal

Boom DOWN signal

Arm IN signal

Arm OUT signal

Bucket CURL signal

Bucket DUMP signal

Swing signal

Travel spd select signal

Bucket confluence signal

Controller

Fuel level sensor

Hydraulic oil temp sensor

Hydraulic oil temperature signal

Relay

PPC lock signal

Starting signal

Preheating signal

Heater relay

Engine speed

Motor dirve signal

Throttle position feedvack signal

Engine oil pressure

Coolant temp sensor

Engine speed sensor

Oil pressure switch

Coolant temp sensor

Alternator

Starting motor

Elct. intake air heater

Motor

Potentiometer

Engine

R.Pump EX press. singal

F. Pump EX press. signal

F. Pump control signal
R. Pump control signal

Charging indicator

Power supply

Safety relay

Fuel level signal

Structure and Function

SY215C

4-174

Remark:

The diagram above illustrates the electrical control system. For hydraulic circuit diagram, see Hy-
draulic System section.

ZX225-1102049

15
14

PsP

XBp2

PnA2

R. travel pressure sensor

Boom UP pressure sensor

Arm IN pressure sensor

Arm OUT pressure sensor

Bucket CURL pressure sensor

Bucket DUMP pressure sensor

Swing pressure sensor

L. travel pressure sensor

Boom DOWN pressure sensor

PPC
Valve

PPC Basic pressure

PPC Lock
solenoid
valve

Bucket

merge

solenoid

valve

Swing

priority

solenoid

valve

Trave

speed

solenoid

valve

F. Pump oil-feed device

Work equipment actuator

Proportional valve

Servo

Main pump

Swing motor

Travel motor

Servo

Travel motor

Proportional valve

F. Pressure sensor

R. Pressure sensor

R. Pump oil-feed device

Work equipment actuator

Control valve
entrance

Main valve

Structure and Function

SY215C

4-175

4.9.3

Engine and pump composite control function

ZX215-1002186

MIN

MAX

LED

MEMORYON

DOWN

RPW

A/I

ESC

Enter

Arm IN/OUT

PPC valve

Travel

Boom UP/DOWN

Bucket DIG/DUMP

Operator cab

Fuel control dial

Monitor

Travel

Swing

MC Controller input

H/S/L/B

Auto-idle cancel

Travel speed swithing

Alarm output

Pressure
sensor

Backup pressure
sensor

Pilot oil pressure

KC controller

Pressure
sensor

Pump proportional
pressure reduce
solenoid valve

Main control valve

Throttle motor

Motor

Potentio-
meter

Engine
Oil-feed
adjustment

Engine chamber

Pump

R. Pump control angle

F. Pump control angle

Engine speed

Actual throttle position feedback

Control motor

Fuel, coolant temp and others

PWR resouce DC24V

(Battery)

CAN path

Calibrator

Structure and Function

SY215C

4-176

Function

●

This function allows the operator to select
a working mode according to the job to
be performed and change engine power
output. Four different working modes are
available: H, S, L and B. To select a work-
ing mode, use the working mode selector
switch on the machine monitor.

●

The main controller controls the pump so
that it can absorb all the torque at the out-
put points of the engine depending on the
pump absorption torque speci

ed for each

mode, rotation set by the fuel control dial,
and actual engine speed.

Specifi cations

H mode

Speed(Rpm)

~1600

1600~1800 1800~2000

Power (KW)

102

110

116

S mode

Speed(Rpm)

~1600

1600~2000

Power (KW)

102

104

L mode

Speed (Rpm)

~2000

Power (KW)

ZX215-1002187

Engine torque

Engine speed N

ZX215-1002188

Engine power

Engine speed N

ZX215-1002189

Pump output pressure

Pump delivery

Structure and Function

SY215C

4-177

Control method of each working mode

●

H mode

●

The matching point of H mode: rated
speed 116kW/2000rpm

●

If pump load increases and pump pressure
rises, engine speed drops. In this case,
engine speed will rise to near the match-
ing point, allowing the pump controller to
reduce pump discharge. On the contrary, if
pump load decreases and pump pressure
drops, pump controller will continue to in-
crease pump discharge until engine speed
reaches the matching point.

ZX215-1002190

Engine torque

Engine speed N

ZX215-1002191

Engine power

Engine speed N

ZX215-1002192

Pump output pressure

Pump delivery

Structure and Function

SY215C

4-178

●

S mode/B mode/L mode

●

At this time, the controller keeps the pump
oil-suction torque in line with the stabling
motor curve, and controls engine speed
through combined control of the engine
and pump.

Power output of each working mode

Mode

Power output rate

90%

80%

70%

ZX215-1002193

Engine torque

Engine speed N

ZX215-1002194

Engine power

Engine speed N

ZX215-1002195

Pump output pressure

Pump delivery

Structure and Function

SY215C

4-179

4.9.4

Pump control function

ZX215-1002196

ESC

Enter

Swing signal

Bucket DUMP signal

Bucket DIG signal

Arm OUT signal

Arm IN signal

R. Travel signal

L. Travel signal

Boom UP signal

Boom DOWN signal

Speed
sensor

Engine

Fuel injection
pump

Governor
motor

Main
pump

Servo

Press.sensor

(Throttle position feedback signal)

(Motor drive signal)

Fuel control dial

(Control signal)

(Engine speed signal)

Proportional

valve

Proportional

valve

Monitor

(CAN

bus)

Engine controller

Structure and Function

SY215C

4-180

4.9.4.1 Electrical positive fl ow control

ZX215-1002197

MAX

Arm OUT PPC pressure

Bucket CURL PPC pressure

Bucket DUMP PPC pressure

L. Travel PPC pressure

Swing PPC pressure

Arm IN PPC pressure

Boom RAISE PPC pressure

Pump 1
delivery
amount

Corresponding
delivery output

Structure and Function

SY215C

4-181

ZX215-1002198

Pump 2
delivery
amount

Boom RAISE PPC pressure

Arm IN PPC pressure

Arm OUT PPC pressure

Bucket CURL PPC pressure

Bucket DUMP PPC pressure

Boom LOWER PPC pressure

R. Travel PPC pressure

MAX

Corresponding
delivery output

Structure and Function

SY215C

4-182

Function

●

Use the work equipment and swing pilot
pressure signal directly as the hydraulic
pump discharge control signal. Pilot pres-
sure is applied on the valve stem and, on
the other hand, is collected by the control-
ler. The controller keeps the discharge
amount of the hydraulic pump at the speci-

ed value of the corresponding pilot pres-

sure according to the functional relation
between the set hydraulic pump discharge
amount and pilot pressure. During com-
bined operation, the set discharge amount
of each operation shall be added.

Operation

●

When the work equipment is operating, the
controller collects the signal of pilot pres-
sure sensor, and determines the control
discharge amount of pump 1 and pump 2
according to the pressure signal.

Structure and Function

SY215C

4-183

Function

●

Calculation of theoretical maximum dis-
charge amount of the pump. The system
applies constant power control. The two
adjustor act together hydraulically, and
keep two executing unit of the same speci-
fication and acting together in synchroni-
zation. The change of pump discharge is
determined by the sum of operating pres-
sure of the two hydraulic pumps

∑

. When

is met, the sum of the

power of the two hydraulic pumps remains
constant below the power of the engine.

Operation

●

When the work equipment is operating, the
controller collects the pressure sensor sig-
nal of pump 1 and pump 2, and realize the
pump constant power control according to
the main pressure signal.

4.9.4.2 Constant power control

ZX215-1002199

Max

Pressure

Flow

Pump P-Q curve

Structure and Function

SY215C

4-184

Function

●

Changing of the engine speed due to load
change controls the pump power, and en-
gine output can be used more efficiently.
(This function can also prevent the engine
from losing control when the machine is
operating under harsh conditions (eg. high
- altitude area).

Operation

The engine control panel controls the target
operating speed of the engine.

●

The engine controller collects the actual
speed signal from the speed sensor, and
preforms a closed loop control with the tar-
get operating speed. Then, the controller
involves the output of closed-loop control
with the calculation of the solenoid valve
control signal, and sends the final adjust-
ing current signal to the pump proportional
solenoid valve.

●

The solenoid valve feeds pilot pressure oil
to the pump adjustor according to the sig-
nal of the controller, and controls the pump
discharge amount.

4.9.4.3 ESS control

Structure and Function

SY215C

4-185

4.9.5 Valve control function

Valve control function

●

Bucket

ow control

●

Swing priority control

ZX215-1002200

ESC

Enter

Main valve

Bucket Confluence

Swing priortity

Engine

Fuel injection
pump

Governor
motor

Speed
sensor

Servo

Main
pump

Press.sensor

(Control signal)

(Engine speed signal)

(Throttle position feedback signal)

(Motor drive signal)

Fuel control dial

Proportional

valve

Proportional

valve

(CAN

bus)

Monitor

Controller

Swing signal

Bucket DUMP signal

Bucket DIG signal

Arm OUT signal

Arm IN signal

R. Travel signal

L. Travel signal

Boom UP signal

Boom DOWN signal

Structure and Function

SY215C

4-186

Function

●

Control the pump swash plate angle ac-
cording to the operation of bucket control
lever.

Operation

●

When the bucket control lever is operated,
the controller collects the signal from the
bucket DUMP pressure sensor and bucket
CURL pressure sensor, and controls the
bucket con

uence proportional valve.

4.9.5.1 Bucket fl ow control

ZX215-1002201

Max

Min

Swash plate angle

Bucket control lever
PPC pressure

ZX215-1002202

750mA

300mA

Bucket confluence
proportional
valve current

Bucket control lever
PPC pressure

Structure and Function

SY215C

4-187

4.9.5.2 Swing priority control

Function

●

Pressurized oil from pump 1 bypasses
bucket 1 valve spool, and flows first to
swing motor valve spool to activate swing

rst.

Operation

●

When signals from pump 1 pressure sen-
sor, arm pressure sensor and swing pres-
sure sensor meet the following conditions,
the controller activates the solenoid valve.
The solenoid valve conducts pilot pressure
oil to arm

ow controller and limits the al-

ternate circuit of arm 1 valve spool. Swing
valve spool first ensures swing motor
power, preventing the counter acting force
when the arm is retracting from affecting
the positioning of the upper swing struc-
ture.

Operating condition

●

Swing pressure sensor: signal output avail-
able

●

Arm pressure sensor: signal output avail-
able

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