Basic Component Testing
Basic
Component Testing
Computer Controlled Systems Cont
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Computer Controlled Systems Cont
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Component 'Testing
Component testing with a meter generally requires detailed schemat-
ics and specifications that are provided by the manufacturer. The
following section provides general information for the main groups of
sensors (input) devices and actuators (output) devices.
The primary input devices (sensors) are:
Temperature sensors
2-wire devices
3-wire devices
Oxygen sensor
Pressure sensors
Primary output devices (actuators) are a form of an electromagnet
that is either ON or OFF. The ONIOFF signal, in general, will be in one
of three configurations:
ON or OFF only (switch)
Pulse width in a specified length of time (fuel injector)
Duty cycle measured in percent of high or low time or dwell
degrees (mixture control solenoid)
Duty Cycle, What is
it?
Duty Cycle is the
percentage
(%I
of
time
a voltage is positive
campared to negative: ON com-
pared to OFF.
For example; duty
cycle measurements are used for
Mixture Control solenoids. The
amount of ON time is measured
as a percent of the total ONIOFF
cycle. The meter can read the
negative
(-)
or positive
(
+
slope
and display
it
as a percent
(%I
of
the total cycle.
Frequency
(Hz),
What is
it?
Posltlve
Duty Cycle
Frequency is the
number
of
times
a voltage pattern repeats positive
compared to negative:
ON
com-
pared to OFF, during one
(1)
sec-
ond of time.
For example; fre-
quency
(Hz)
measurements are
,
specified for digitally controlled
Manifold Absolute Pressure sen-
sors. The frequency of the
ON1
OFF signals per second are mea-
sured and displayed.
Frequency
(Hz)
is shown as Ana-
log: A continuous positive to nega-
tive cycle; or Digital: A positive to
negative10N to OFF cycle.
J
+
Volts
-
0
Volts
Analog
Slgnal
+
Volts
-
0
Volts
-
L.,1
Dlgltal Slgnal
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