Jinhan ADO102 Manual page 20

①The same as the crankshaft, camshaft position sensor Step 1.
②Select "Sensor" after entering the main menu, then enter the sub-menu press the arrow
keys to select "air flow meter sensor" into the second sub-menu press the arrow keys to
select "high frequency" or "low frequency", press "OK" button to confirm to enter the
oscilloscope user interface.
③
Connect the CH1 probe to the oscilloscope and set probe to 1X file transfer, then
connect the grounding clip to the signal ground or grounding.
④Since the oscilloscope "air flow meter sensor" function has already default settings
(High Frequency: Probe file 1X, time base range 100us, low frequency: probe profiles 1X,
time base range 10ms),Just probe to the corresponding signal, To intuitive display
waveforms, as shown in Figure 8. (note: As in the "SCAN" scan mode requires patience
waveform scanned)
⑤
Press "CH1", you can view the value and configuration (by default)
⑥
waveform can be self-fulfilling their needs by adjusting the time base, vertical volts /
division and trigger mode (time base, vertical volts / division and other specific operations,
please refer to the Universal oscilloscope operation).
Note:
air flow meter is generally divided into analog air flow meter and digital air flow meter:
●Analog air flow meter
The function of the air flow meter is to measure the air flow into the throttle valve. The air
flow into the throttle valve is different with the speed of the engine. Analog air flow meter
will detect the flow of air into the change of 0-5V between the voltage signal transmitted to
the oscilloscope. Start the engine, step on the accelerator pedal, then the air flow signal,
should be with the throttle valve opening bigger and the higher the value.
In the idle speed should be kept stable, when the throttle valve is fully open, the signal will
be increased to the maximum value.
Watch the waveform signal in the abnormal phenomenon, such as: if the waveform
smoothly, no surge occurred suddenly, waveform distortion, usually said oscilloscope
between sensor and circuit, has the situation bad, bad line or the sensor itself.
Sensor voltage output signal, usually at idle speed when the minimum and with the
increase of the engine load, the average idle speed is about 800mv, when the throttle
valve is fully open, about 4.5V.
● Digital air flow meter
The function of digital air flow meter is to measure the air flow into the throttle body. Air
flow into the throttle body varies with the speed of the engine. Digital air flow meter
converts the detected air flow into the frequency signal. When the higher frequency signal,
the greater the amount of air. Start the engine, at this time will be displayed on the screen
square wave graphics, without any waveform display. You may have entered the analog
air flow meter.
The observed signal waveform anomalies, for example, whether a square wave at right
angles to change, or whether the surge occurs and the like. Sensor signal waveform
sudden change in frequency usually indicates that there is a bad contact between the
oscilloscope and the sensor, or the sensor itself is poor.
Digital waveform generated by air flow meter square wave signal neat, when the ignition
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