TSI Incorporated 8587A, Руководство по эксплуатации и обслуживанию

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Instrument Operation 4-5
5. Press the DOWNSTEAM keypad to switch to the downstream sample
mode. Wait for the voltage to stabilize (20 seconds). Over a minute
interval, record 10 data points. Fit factor is often based on the worst-
case, e.g., highest aerosol level, include the highest voltage seen. This
value is used to determine worst-case Fit Factor.
voltage Zero - voltage Downstream Highest
voltage Zero - voltage Upstream
case) (worst Factor Fit

Average fit factor can be determined by averaging the voltages and
subtracting the Zero Voltage.
voltage Zero - voltage Downstream Average
voltage Zero - voltage Upstream
factor fit Average

Fit Test Under Computer Control
The following is an example sequence for performing fit tests using a
computer program for control and data acquisition. Delay and sample times
are presented as examples. Actual delays and sample times should be
determined based on lengths of tubing and other characteristics or
limitations of the test system.
The mask sample presented here is averaged. Often it is necessary to
know instantaneous leak rates to evaluate worst-case fit. When this is
necessary, mask data should be taken and recorded at short intervals
(e.g., each second) and the highest number used to characterize fit. When
exercises are performed mask data can vary significantly over the mask
test sequence.