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Note: The pump noise and vibration may increase during background measurements.
Note: Selecting [STOP] during a background measurement cancels the measurement and
indicates a [BG] value of zero.
Consequently, the background level is not subtracted from the next dust
measurement.
That completes the procedure for measuring the background. With the pump still running,
adjust the sensitivity level as described below in 8-1-2 Adjusting the Sensitivity Level.
8-1-2 Adjusting the Sensitivity Level
The measurement sensitivity of dust indicators can vary due to contamination inside the
detector, deterioration of electrical parts, misaligned optical components caused by vibration,
or other factors. To correct for such variations, a standard scattering plate is measured before
dust measurements and then a correction factor is calculated based on prespecified values.
This correction factor is used to correct subsequent measurements to ensure sensitivity
remains the same as when shipped or last calibrated.
Note: Adjust sensitivity immediately after 8-1-1 Background (BG) Measurement.
Sensitivity Adjustment Procedure
(1) Align the mark on the scattering plate knob to
the [SENSI.ADJ.] position and push in the
knob.
→
The pump stops (the [MEASURE] lamp
switches OFF.
If the background measurement was not
completed normally, "CALIBRATION FAIL!" is
displayed.
In that case, select [START] again to remeasure
the background.
Indicator
mark
