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Operation
Functional Description
The H1, H2, K1, and K2 controls consist of a ported housing mounted on the multiblock. It contains a
solenoid valve and internal porting to direct the external variable signal pressure through the solenoid
valve to the end of the 4-way valve. A threshold spring and ramp spring(s) act on the opposite end of the
4-way valve.
Solenoid Valve
The solenoid valve (M1) is a 2-position 3-way valve that passes the external signal pressure to the end of
the 4-way valve, or blocks the external signal and drains the end of the 4-way valve to the motor case.
The H1 and K1 solenoid valves have a 12-volt coil with DIN connector. The H2 and K2 solenoid valves
have a 24-volt coil with DIN connector. The 4-way valve and the solenoid valve are the same for H1, H2,
K1, and K2 controls. The control housings are different between the H1, H2, and the K1, K2 controls. The
logic for the control is:
•
If H1 or H2 are energized operation is proportional; if de-energized output is maximum displacement.
•
If K1 or K2 are energized, output is maximum displacement; if de-energized, operation is
proportional.
Refer to
Multiblock
on page 8
Pressure Compensator OverRide (PCOR) Function
on page 8 and
Brake
Pressure Defeat (BPD) Option
on page 9 for multiblock, PCOR and brake pressure defeat information.
H1, H2 Schematic
P107 825
T2
T1
B
A
T7
max.
disp.
L2
M4
M3
M2
M3 (M5)
T8
T3
L1
M1
X1
M7
T6
T4
U6
U7
T5
XA
XB
Multiblock
PCOR Valve
BPD Spool
Shuttle
Loop Flush
4-Way Valve
Repair
The solenoid valve (M1) is available as a complete assembly only. Do not remove unless it is being
replaced.
Service Manual
Series 51 Hydraulic Proportional Controls Service Manual
H1, H2, K1, K2 Controls
11009446 • Rev BA • July 2014
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