Doosan 25/300, Electronic Service Manual

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Book No. 22772784 (9--8--06)
HP1300/1600WCU Electrical Manual
Software versions under 2.0 use the frequency throttle
to communicate with the engine. A square wave
frequency signal from 150 Hz to 375 Hz is sent from
the WEDGE controller to the engine controller.
The signal is a linear signal from 150 Hz at engine idle
(1200 RPM) to 375 Hz at maximum run speed (1800
RPM).
Figure 2--2 shows the signals between the engine
controller and the WEDGE controller.
Sensors and Transducers
The electronics system contains sensors and
transducers that are used to collect data from the
compressor. The temperature is measured by a
thermistor. This device exhibits a change in resistance
as the temperature changes. The resistance causes
an input voltage change to the WEDGE controller
input and is interpreted as a temperature change.
The electronics system also uses pressure
transducers to measure compressor pressure
changes. These devices have an output signal of .45
VDC to 4.5 VDC, corresponding to 0 psi and the
maximum measured psi for a particular device. The
maximum pressure transducer ranges are 100 or 225
psi. The 100 and 225 psi devices are gauge pressure
devices. These transducers are provided with 5 VDC
excitation to power the device. These are three wire
devices: excitation, signal and ground.
Digital Inputs and Outputs
The WEDGE controller scans digital inputs such as
switch contacts. These are either “ON” (24VDC) or
“OFF” (0 VDC). These digital inputs are connected to
switches within the package such as the key start
switch, air filter switches and IQ filter switches.
The WEDGE controller provides 24 VDC digital
outputs to control solenoids, start compressor and DC
heaters. These are 24 VDC “ON” and 0 VDC “OFF”.
They are current limited and short circuit protected.
Controller Outputs
The WEDGE controller has three types of outputs:
frequency, pulse width modulated (PWM) and 24 VDC
digital (ON /OFF). The frequency output is used as a
throttle signal for the engine (software revisions less
than 2.0).
The WEDGE controller varies the frequency from 150
Hz to 375 Hz, corresponding to 1200 to 1800 RPM.
The frequency signal is a 50% duty cycle, 24 VDC,
square wave. This throttle signal is used with the
Cummins engine.
The PWM signal is used as a throttle signal for the
Caterpillar engine. It has a base frequency of 500 Hz
and the duty cycle varies from 10% to 90%.
Pressure Control
The discharge pressure is controlled by manipulating
the engine speed and compressor inlet valve position.
The inlet valve position is controlled pneumatically and
the engine speed is determined by the WEDGE
controller. The WEDGE measures the pneumatic
system regulation pressure and computes an engine
throttle setting. This throttle setting is sent to the
engine via the frequency throttle, PWM or J1939
throttle, depending on which technique is used. The
engine controller will control engine speed to this
throttle setting.
Electronic Engine
The HP1600/1300 machine contains an emissions
certified diesel engine. In order to meet the emissions
requirements, the engine has an electronic control
system.
The control system handles all monitor, alarm and
control functions for the engine. The WEDGE control-
ler communicates with the engine controller over the
J1939 CAN network.
The WEDGE controller sends throttle settings to the
engine (software revisions 2.0 and greater) and
receives diagnostic and run time data from the engine
over the J1939 CAN network. A frequency throttle
interface with the engine is used for software revisions
earlier than 2.0. Figure 2--2 shows the connections
between the WEDGE controller and the engine
controller.