DH Instruments E-DWT-10000-AF, Руководство по эксплуатации и обслуживанию

Страница: 43 / 134

3. OPERATION
Page 33 © 2008 DH Instruments, a Fluke Company
[ESC] can be used to abort the running leak test. [ENT] while the leak test is running restarts
the leak check timer. When the leak check timer countdown has completed,
RPM4-E-DWT beeps three times and the leak check results screen is displayed:
1. Total pressure change from start to finish of leak check time.
2. Indicator of Q-RPT used to run the leak check.
3. Average rate of change of pressure over the leak check
time period (
∆
P/time in seconds).
∆
P 0.61 kPa a Hi
Rate 0.06 kPa/sec
From the leak check results screen, press [ENT] to repeat the leak test.
Press [ESC] to return to leak check main menu and exit to the MAIN RUN screen.
To view the results of the most recently completed leak check, press <2view> . If NO leak
check data is stored (i.e., if the RPM4-E-DWT has never run a leak test or a reset has
cleared previous leak test results), the results screen displays
<Data NOT available> briefly
and returns to MAIN RUN screen. Press [ENT] or [ESC] to return to the MAIN RUN screen.
Leak check is range specific in the sense that a leak check is run using the active range.
However, only one set of leak check results is maintained in memory and each leak test completed
overwrites the memory. View leak check always shows the results of the last leak check run
regardless of the range that is now active. The results screen includes the range indicator to
indicate the range in which the leak check was run.
3.7.7 [DISPLAY]

PURPOSE
To select, from a variety of choices, the information that is displayed on the second line of the
RPM4-E-DWT display.

PRINCIPLE
RPM4-E-DWT supports a variety of advanced pressure measurement functions that are
displayed on the second (bottom) line of the RPM4-E-DWT display. In summary, the
available display functions included are:
AVERAGE Calculates the average measured pressure over a user specified period of time
and displays the average, the standard deviation about the mean and a
countdown in seconds to the next average (see Section 3.7.7.1). This function is
often used to filter out pressure noise in an unstable system. The magnitude of the
noise is quantified by the standard deviation about the mean. A second Avg
screen allows the instantaneous pressure values to be viewed during an
averaging cycle.
RATE Calculates and displays the current rate of change of pressure in current
pressure units/second (see Section 3.7.7.2). This function is a useful indication
of the stability of the pressure being measured. It is often used as an indication
of positive or negative leak rate and as a go/no go criterion of when to take
data when comparing RPM4-E-DWT and a device under test, for example in a
calibration. Rate is used by the Ready/Not Ready function to determine when
a Ready condition exists (see Section 3.1.2).
DEVIATION Continuously calculates and displays the difference between the pressure
measured by RPM4-E-DWT and a target pressure entered by the user (see Section
3.7.7.3). This function is useful in monitoring the evolution of pressure around
and/or away from a desired set point.