User Manual

30 SENR9977
Systems Operation Section
Open Circuit – An open circuit is a broken electrical
wire connectio
n. The signal or the supply voltage
cannot reach the intended destination.
Original Equi
pment Manufacturer (OEM) – An
OEM is the manufacturer of a vehicle that utilizes a
Perkins engine.
Parameter – A parameter is a programmable value
which affects the characteristics or the behavior of
theenginean
d/or vehicle.
Parameter Identifier (PID) – A PID is a numerical
code that con
tains two digits or three digits. A
numerical code is assigned to each component. The
numerical code identifies data via the data link to the
ECM.
Password – A password is a group of numeric
characters
or alphanumeric characters. A password
is designed to restrict the changing of information
in the ECM. The electrical engine systems require
correct cu
stomer passwords in order to change
customer specified parameters. The electrical engine
systems require correct factory passwords in order
to clear ce
rtain logged events. Factory passwords
are also required in order to change certain engine
specifications.
Personality Module – The personality module is the
module in the ECM which contains all the instructions
(softwar
e) for the ECM and performance maps for
a specific horsepower family. Updates and rerates
are accomplished by electronically flashing in new
data. The
updates and rerates are flashed in using
the electronic service tool.
Power Ta
ke-Off (PTO) – The PTO is operated with
the cruise control switches or dedicated inputs from
the PTO. This mode of operation permits setting
constan
t engine rpm when the vehicle is not moving
or when the vehicle is moving at slow speeds.
Pulse Wi
dth M odulation (PWM) – APWMisa
digital type of electronic signal that corresponds to a
measured variable. The length of the pulse (signal) is
contro
lled by the measured variable. The variable is
quantified by a certain ratio. This ratio is the percent
of “on-time” that is divided by the percent of “off-time”.
APWMsi
gnal is generated by the Throttle Position
Sensor.
g00284479
Illustration 38
Example Of Pulse Width Modulation
Rated Fuel Position (“Rated Fuel Pos”) – The
rated fuel position indicates the maximum allowable
fuel position (longest injection pulse). The rated fuel
position will produce rated power for this engine
configuration.
Reference Voltage – The reference voltage is a
regulated voltage that is used by the sensor in order
to generate a signal voltage.
Sensor – A sensor is used to detect a change in
the pressure, in the temperature, or in mechanical
movement. When any of these changes are detected,
a sensor converts the change into an electrical signal.
Service Program Module (SPM) – The SPM is
a software program on a computer chip that was
programmed at the factory.
Short Circuit – A short circuit is an electrical circuit
that is mistakenly connected to an undesirable point.
For example, an electrical contact is made with the
frame whenever an exposed wire rubs against a
vehicle’s frame.
Signal – A signal is a voltage or a wave that is used
to transmit information that is typically from a sensor
to the ECM.
Speed Surge – A speed surge is a sudden brief
change in engine rpm.
Speed-timing Sensor – The speed-timing sensor
is a sensor that provides a Pulse Width Modulated
signal to the ECM. The ECM interprets this signal as
the crankshaft position and the engine speed.
Subsystem – A subsystem is a part of the engine
system that relates to a particular function.