Manitowoc MLC650, Руководство по техническому обслуживанию

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Reference
Only
Manitowoc
Published 09-09-16, Control # 229-09
3-19
MLC650 SERVICE/MAINTENANCE MANUAL ELECTRICAL SYSTEM
3
Pressure and Vacuum Switches
The pressure and vacuum switches are normally closed. The
switches open when the vacuum or pressure level exceeds
the setting of the switch.
A controller digital output provides power to the switch.
In the non-tripped state, the normally closed contact allows
power to be sent through the center terminal of the switch,
then back to a controller digital input to be read as a logic
high.
When the switch is tripped, the normally closed contact
opens, breaking the path of power through the center
terminal, and the controller reads this as a logic low.
Relays
A controller digital output drives the relay coil. The coil
energizes, creating a magnetic field that closes the relay
contacts. Relays use a small control signal to control the flow
of a large current.
Warning Lights
A controller digital output powers the warning lights.There
are warning lights for the following crane systems:
• VPC
• Boom top
Camera Lights
A controller digital output powers the camera lights.There
are camera lights for the following:
• Drums 1 to 6
• VPC-MAX rear camera
Hand Throttle
A controller provides an 8.5 V
DC
supply to a potentiometer
that is connected to the hand throttle. Power is applied
across the potentiometer windings to ground. Moving the
hand throttle moves a wiper across the potentiometer
windings. The voltage provided at the wiper when referenced
to ground is proportional to the hand throttle position and is
sent to a controller analog input.
Foot Throttle
A controller provides a digital output to a potentiometer that
is connected to the foot throttle. Power is applied across the
potentiometer windings to ground. Moving the foot throttle
moves a wiper across the potentiometer windings. The
voltage provided at the wiper when referenced to ground is
proportional to the foot throttle position and is sent to a
controller analog input.
Travel and Free-Fall Brake Pedals
A controller digital output provides power to a potentiometer
that is connected to the pedal. Power is applied across the
potentiometer windings to ground. Moving the pedal moves
a wiper across the potentiometer windings. The voltage
provided at the wiper when referenced to ground is
proportional to the pedal position and is sent to a controller
analog input.
Pump Displacement Controls
Pump flow is both directional and variable, determined by
position and stroke of a proportional solenoid valve.
A controller sends two pulse-width modulated (PWM) output
signals to two coils that actuate the solenoid valve in
opposite directions. As a PWM duty cycle increases at one
coil, more fluid is ported to the swashplate servo pistons
through the solenoid valve, increasing the swashplate angle
in the direction commanded. As the swashplate angle
increases, so does the piston stroke within the pump,
increasing the pump output volume.
RCL Beacon
A controller provides a digital output to each indicator in the
RCL beacon (red, amber, and green).
Wind Speed Indicators
A controller digital output provides power to the wind speed
sensor. The sensor produces an analog signal that is
proportional to the wind speed. A controller analog input
reads this signal, and the controller software determines the
wind speed based upon the signal level.
Proximity Sensors
A controller digital output provides power to the proximity
sensor.
Proximity sensors sense metal objects by generating
magnetic fields. When no metal object is close to the sensor,
the solid state switch within the sensor is open and there is
no output signal. When a metal object is close to the sensor,
the switch within the sensor closes and outputs a signal
which is 1.8 V
DC
less than the sensor supply voltage.
A yellow LED on the sensor indicates the switch state.