RPM4™ OPERATION AND MAINTENANCE MANUAL

[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 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 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.

3.3.6 [DISPLAY]

PURPOSE

To select, from a variety of choices, the information that is displayed on the second line of the RPM4 display.

PRINCIPLE

RPM4 supports a variety of advanced pressure measurement functions that are displayed on the second (bottom) line of the RPM4 display. In summary, the available display functions included are:

AVERAGE Calculates the average pressure measurement 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 3.3.6.1). 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 3.3.6.2). 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 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 3.2.1).

DEVIATION Continuously calculates and displays the difference between the pressure measured by RPM4 and a target pressure entered by the user (see Section 3.3.6.3). This function is useful in monitoring the evolution of pressure around and/or away from a desired set point.

© 2004-2007 DH Instruments, a Fluke Company

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Fluke RPM4 manual Display, ∆P 0.61 kPa a Hi Rate 0.06 kPa/sec