MH860 series hydraulic servo drive
Multi-pump combined flow control
83
Oil outlet 3
Oil outlet 2
Pressure sensor
Pressure sensor
Pressure
sensor
M1
P
Slave
node
E/C
M3
P
Master
node
E/C
M5
P
Slave
node
E/C
CAN
CAN
Oil outlet 1
F
lo
w
re
fe
re
n
c
e
P
re
s
s
u
re
re
fe
re
n
c
e
F
lo
w
re
fe
re
n
c
e
F
lo
w
re
fe
re
n
c
e
P
re
s
s
u
re
re
fe
re
n
c
e
P
re
s
s
u
re
re
fe
re
n
c
e
7.4 Multiple modes
The system consists of three nodes, of which each node consists of one or more single-pump
systems. A single-pump system is called a control unit. A node consisting of one control unit is
an independent unit node, while a multi-unit node consisting of multiple control units can be
regarded as a node consisting of a dual or multiple pumps. A multi-unit node consists of a
control unit and one or more following units. Each node has a pressure sensor connected to
the control unit, while the control unit is connected to the upper control system through the
AIN1 and AIN2 analog interfaces to receive pressure and flow reference signals. The two DA
outputs of control unit connect to the analog inputs AIN1 and AIN2 of following unit to function
as the motor speed reference signal and drive enabling signal. The RDY outputs of following
unit are in serial connection, with the positive end connected to the 24V power supply, while
the negative end connected to digital input port I7 of control unit, through which the control
unit obtains the run status of following unit drive.
Each node uses the digital input signal I1(C/D) to switch the control mode. When I1(C/D) is
high, the node works in flow combining state. When I1(C/D) is low, the node works in flow
splitting state. When the system works in the flow combining state, the number of nodes with
flow combined can be changed. The master node completes pressure control and total
system flow control. The master and slave nodes run at the same speed in flow combing state.
The flow distribution algorithm described earlier is not applicable to the multi-mode method.
The control unit of each node controls the pressure and flow in flow splitting mode, and the
following unit keeps the same speed as the control unit.
Multi-mode systematic diagram: