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Book No. 22103592 (7/05) NHP1500 Electrical Manual
Controller Outputs
TheINTELLISYScontrollerhasthreetypesofoutputs:
frequency,pulsewidthmodulated(PWM)and24VDC
digital (ON /OFF). The frequency output is used as a
throttle signal for the engine. The INTELLISYS
controllervariesthefrequencyfrom150 Hzto375Hz,
corresponding to 1200 to 1800 RPM. The frequency
signal is a 50% duty cycle, 24 VDC, square wave.
The PWM signal is used to control the speed of the
aftercooler fan. It is a 125 Hz frequency signal, 24
VDC with a duty cycle of 5 % to 90%.
The INTELLISYS controller provides 24 VDC digital
outputsto controlsolenoids,alarm horn,strobe lights,
DC heaters and the fuel pump. These are 24 VDC
“ON” and 0 VDC “OFF”. They are current limited and
short circuit protected.
Theymayhaveavoltagelevelof.5VDCto1.4VDCin
the OFF state due to transistor leakage of the
darlington drivers in the circuit.
Pressure Control Loop
The INTELLISYS controller controls discharge
pressurebymodulatingenginespeed. Thedischarge
pressure setpoint is entered at the INTELLISYS
controller front panel. The control loop will modulate
the engine speed between 1200 RPM and 1800 RPM
to maintain the selected discharge pressure. The
INTELLISYS controller is actually providing a throttle
signaltotheenginecontrollerwhichinturncontrolsthe
engine speed.
Electronic Engine
The NHP1500 machine contains an emissions
certifieddieselengine. Inorderto meettheemissions
requirements, the engine has an electronic control
system.
The control system handles all monitor, alarm and
control functions for the engine. The INTELLISYS
controller communicates with the engine controller
over the J1939 CAN network.
The INTELLISYS controller receives diagnostic and
run time data from the engine over the J1939 CAN
network. Afrequencythrottleinterfacewiththeengine
is used. Figure 2--2 shows the connections between
the INTELLISYS controller and the engine controller.
J1939 Data Link
The CAN network is a single pair shielded cable
located with or attached to the W1 main harness.
Figure 2--3 shows a layout of the CAN harness or
“backbone” as it is referred to. The termination
resistors (Terminator) are important to prevent
reflections on the transmission line and must be in
place for the network to function properly. The shield
from the cable is connected to the machine metal at
theINTELLISYScontrollerend. Thisconnectionmust
be properly made with good metal--to--metal contact
between the wire terminal and the machine metal.
Theenginediagnosticsconnectorislocatedinsidethe
control panel. This is used to connect the engine
manufacturer’sservicetoolstotheCANnetwork. This
connector also provides 24 VDC to power these
service tools. If computer based service tools are not
available, the lamp and switch panel, or engine status
menuor IRElectronicServiceManual,canbe usedto
extractenginecodes. Referto engineservicemanual
for details of their use.
Electrical System
Theelectricalsystemconsistsofthewiringharnesses
and associated electrical devices such as relays,
switches, lights, solenoids and alarm horn. There are
fourwiringharnessesintheNHP1500machine. They
are as follows:
22079180 W1 Chassis Main Harness
54597497 W2 Control Panel Harness
54633003 W3 Fuse Box Harness
The schematic diagrams show the connections for
these harnesses. Figure 2--1 is a system schematic
showing harness connection with devices and
controllers. Section 8 includes information on
connectors used in the harnesses.
