Manitowoc MLC650 Service Maintenance Manual

Reference Only
SWING SYSTEM MLC650 SERVICE/MAINTENANCE MANUAL
6-2
Published 09-09-16, Control # 229-09
SWING OPERATION
Swing Pump Control
The swing pump is controlled by an electronic displacement
control (EDC). The EDC is a proportional solenoid valve that
determines the swing pump’s output volume and flow
direction.
When a swing command is communicated to the IOLC33
control module via the CAN Bus, the IOLC33 control module
sends a pulse-width modulation (PWM) output signal to the
EDC. The PWM signal is proportional to the speed
commanded by the J1 joystick position. Increasing the PWM
duty cycle increases the pump swashplate angle. As the
swashplate angle increases, so does the piston stroke within
the pump, increasing the pump output volume.
Swing Left
When the J1 joystick is moved to the left, the joystick sends a
swing left command to the IOLC33 control module via the
CAN Bus.
The IOLC33 control module then ramps up the PWM duty
cycle to the proportional solenoid A in the swing pump EDC
to move the pump swashplate to a position that meets the
direction and speed commanded by the joystick position.
The swing pump sends hydraulic fluid out port A on the pump
to port B on the motors via the triple swing manifold. The
triple swing manifold evenly splits the flow from the pump to
the swing motors.
Hydraulic fluid then flows from port A on the motors to port B
on the pump via the triple swing manifold to complete the
closed-loop circuit. The triple swing manifold combines the
return flow from the motors into one stream before flowing
back to the pump.
The swing motor speed sensor and pump 8 port A pressure
transducer (swing left psi) provide closed loop feedback to
the control modules CCM-10 and IOLC30.
Swing Right
When the J1 joystick is moved to the right, the joystick sends
a swing right command to the IOLC33 control module via the
CAN Bus.
The IOLC33 control module then ramps up the PWM duty
cycle to the proportional solenoid B in the swing pump EDC
to move the pump swashplate to a position that meets the
direction and speed commanded by the joystick position.
The swing pump sends hydraulic fluid out port B on the pump
to port A on the motors via the triple swing manifold. The
triple swing manifold evenly splits the flow from the pump to
the swing motors.
Hydraulic fluid then flows from port B on the motors to port A
on the pump via the triple swing manifold to complete the
closed-loop circuit. The triple swing manifold combines the
return flow from the motors into one stream before flowing
back to the pump.
The swing motor speed sensor and pump 8 port B pressure
transducer (swing right psi) provide closed loop feedback to
the control modules CCM-10 and IOLC30.
Coasting
When the J1 joystick is moved back to the neutral position,
the IOLC33 control module ramps down the PWM signal to
the energized A or B solenoid in the EDC. This allows the
springs to center the spool inside the proportional solenoid
valve, causing the pump swashplate to destroke (moves to
the center position), stopping hydraulic flow to the motors.
With the J1 joystick in the neutral position and the swing
brake not applied, the crane is allowed to coast because of
an orifice located in the triple swing manifold. The orifice is
connected in parallel with ports A and B of the swing motors,
allowing a restricted amount of hydraulic fluid to flow from
one side of the motors to the other side without having to go
through the pump.

Manitowoc MLC650 Specifications

General

Brand	Manitowoc
Model	MLC650
Category	Construction Equipment
Language	English