Autorange]; Leak Ck]/Rate Of Change Measurement - Fluke RPM4-AD Operation And Maintenance Manual

3.3.4 [A R
UTO ANGE
This feature is not used in RPM4-AD models.
3.3.5

[LEAK CK]/RATE OF CHANGE MEASUREMENT

PURPOSE
To run an automated leak check routine that measures the leak rate of the system connected
to the RPM4-AD active TEST port(s). Also used to measure average rate of change over a
specified time period as required to evaluate the rate of change of altitude set by an air data
test set.
PRINCIPLE
The LEAK CHECK function is provided as a means of checking and quantifying the leaks that
may be present in the system connected to the RPM4's active Q-RPT TEST port(s). It is also
used to measure rate of change of altitude over a specified time period (rate of climb).
The principle of the LEAK CHECK function for measurement of a leak is the measurement of
the natural decrease or increase of pressure in a fixed volume over time. The LEAK CHECK
function allows a leak check time to be set. The total pressure change and the average rate
of change over the leak check time are calculated and displayed.
The LEAK CHECK function also measures average rate as required to evaluate the rate of
change of altitude set by an air data test set. To use the function in this way, set the desired
rate measurement time period, then set the rate with the air data test set. When ready, press
[ENT] on the RPM4-AD to start the measurement.
In differential pressure measurement mode (see Section 3.2.6), the leak check
measurement is based on the measurement of the differential pressure.
OPERATION
To run a leak check, first set the pressure to the desired pressure. To verify a rate of change
set by another device (such as an air data test set), first set the rate of change on the device.
Changing the pressure in a test system causes adiabatic temperature changes in the
pressurized medium that need to have dissipated before a valid leak measurement can be
made. In general, a 0.5 to 1 minute wait before running a leak check is adequate to allow
the adiabatic temperature change to dissipate and valid leak measurements to be made.
However, stabilization time may be longer as volume and pressure increases.
To access the LEAK CHECK function, press [LEAK CHECK] from the MAIN RUN screen.
Select <1run> to run a leak test or rate of change measurement. The display is:
1. Edit field for the time over which the rate will be determined,
in seconds.
Edit the rate measurement time if desired (minimum 1, maximum 999 seconds) and press
[ENT].
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3. OPERATION
Set sample time:
15 s
© 2005-2007 DH Instruments, a Fluke Company