ACCESSORIES MLC300 SERVICE/MAINTENANCE MANUAL
10-16
Published 11-22-17, Control # 257-02
CAB TILT CYLINDER
General
This part of Section 10 provides operational information and
electrical and hydraulic schematics for the cab tilt system.
Additional component information for this system can be
found in the following sections of the Service Manual:
• Section 2: Hydraulics
• Section 3: Electrical
The cab tilt cylinder is controlled by the setup remote or by
the S23 cab tilt switch in the cab.
See Figure 10-12
and Figure 10-13 for the following
descriptions.
Setup Remote Control
The setup remote control communicates with the CCM-10
control module via the controller area network bus (CAN
Bus). The crane control modules use the CAN Bus to
communicate with each other.
To operate the setup remote, it must be turned on as
instructed in the MLC300 Operator Manual.
S23 Cab Tilt Switch Control
The IOSA22 control module provides 24 V
DC
to the S23
switch. When the S23 switch is in the cab UP or cab DOWN
position, the switch sends a 24 V
DC
signal back to the
IOSA22 control module. The IOSA22 control module then
communicates the corresponding command to the CCM-10
control module via CAN Bus A.
Neutral
When there is no command from the setup remote or S23
cab tilt switch:
• Pump 4 hydraulic flow through system A (left valve
assembly) decreases.
• The isolation valve A shifts to neutral to block pump flow
to the cab tilt valve.
• The cab tilt valve shifts to neutral to block pump flow to
the cab tilt cylinder.
• The load holding valve closes to lock the cylinder in
position.
Tilt Up
When a tilt up command is initiated by the setup remote or by
the S23 cab tilt switch, the command is sent to the CCM-10
control module. The CCM-10 control module then
communicates the tilt up command to the IOLC32 and
IOLC33 control modules via CAN Bus C.
The following then occurs:
• The CCM-10 control module increases the PWM current
to pump 4 to increase system A (left valve assembly)
hydraulic flow.
• The IOLC33 control module sends 24 V
DC
to the side A
solenoid on isolation valve A, energizing the solenoid.
The CCM-10 control module provides the ground for the
solenoid. The valve spool shifts to a position that routes
hydraulic fluid to the cab tilt valve via an adjustable
pressure compensated flow control valve.
• The IOLC32 control module then sends 24 V
DC
to the
corresponding solenoid on the cab tilt valve, energizing
the solenoid. The valve spool shifts to a position that
routes hydraulic fluid to the load holding valve at the
barrel end of the cab tilt cylinder.
• Hydraulic fluid bypasses the load holding valve by
flowing through a check valve, then to the barrel end of
the cylinder. As hydraulic fluid fills the barrel end of the
cylinder, the rod extends to tilt the cab up. This action
forces hydraulic fluid out the rod end of the cylinder and
back to tank via the cab tilt valve.
Load Holding
If system pressure is lost, the check valve closes and the
load holding valve locks the cab tilt cylinder in position.
Tilt Down
When a tilt down command is initiated by the setup remote or
by the S23 cab tilt switch, the command is sent to the CCM-
10 control module. The CCM-10 control module then
communicates the tilt down command to the IOLC32 and
IOLC33 control modules via CAN Bus C. The following then
occurs:
• The CCM-10 control module increases the PWM current
to pump 4 to increase system A (left valve assembly)
hydraulic flow.
• The IOLC33 control module sends 24 V
DC
to the side A
solenoid on isolation valve A, energizing the solenoid.
The valve spool shifts to a position that routes hydraulic
fluid to the cab tilt valve.
• The IOLC32 control module then sends 24 V
DC
to the
corresponding solenoid on the cab tilt valve, energizing
the solenoid. The valve spool shifts to a position that
routes hydraulic fluid to the rod end of the cab tilt
cylinder.
• Rod-end pilot pressure opens the load holding valve. As
hydraulic fluid fills the rod end of the cab tilt cylinder, the
rod retracts to tilt the cab down. This action forces
hydraulic fluid out the barrel end of the cylinder, through
the open load holding valve, and back to tank via the cab
tilt valve.
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