LAUNCH KES-200 Ignition Waveform
D-3
The resistance-measuring value is displayed on the
center of the screen. User can press [ESC] key to
return to the upper-level menu, or press [HELP] key to
view help information.
Frequency Measuring Mode
Select [4.FREQUENCY] on the main menu, the unit
will enter the frequency-measuring mode. After
grounding the ground cable and connecting the probe
to the object to be tested, the user may measure the
signal frequency of CH1 and CH2 in the range of 1.0
– 100.0KHZ. The display of the frequency-measuring
mode is as shown in Fig.3-06.
Fig.3-06
The display and operation is the same as that for duty
cycle measuring. For further information, refer to the
section “Duty Cycle Measuring Mode”.
Duty Cycle Measuring Mode
Select [5.DUTY CYCLE] on the main menu, the unit
will enter the duty cycle measuring mode. After
grounding the ground cable and connecting the probe
to the object to be tested, the user can measure the
duty cycle of signals in CH1 and CH2 in the
measuring range of 0.0% - 100%.
Duty Cycle:
Duty cycle (or duty ratio) is the percentage of low
voltage time to whole cycle time when the rectangular
wave signals are measured, that is:
Duty cycle = Low voltage time/ (high voltage time +
low voltage time)
×
100%
Duty cycle is especially applicable to check the pulse
control signal, such as action of the idle control motor,
not applicable to frequency and voltage control. The
engine is idling when the action of idle control motor is
being tested. When the air conditioner, power steering
system or other power consumption devices are
running, the load of engine will increase. In this case,
the idle control motor increases the time of action to
increase the engine speed and compensate the
consumption.
Fig.3-07 Waveform of idle control motor
The waveform of idle control motor is displayed in
rectangular, as shown in Fig.3-07.
Low voltage shows that the idle control motor is acting.
Duty cycle is the percentage of low voltage in one
cycle.
Display Format:
Duty cycle interface is displayed as shown in Fig.3-08.
Fig.3-08
The number in the center of the screen is the
measured value of duty cycle for the selected channel.
Other values are displayed in the lower part of the
screen, such as:
One cycle
Low V/T
High V/T
Low V
High
