Fluke A20M-AF Manual Do Utilizador

Página de 148
 
3. OPERATION 
 
Page 31 
© 2007 DH Instruments, a Fluke Company 
  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 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 3.3.6.1).  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. 
RPT 
Allows pressure measurement from the RPM4’s two Q-RPTs to be displayed 
simultaneously (see Section 3.3.6.4). 
HI/LO 
Records and displays maximum and minimum pressures measured (see 
Section 3.3.6.5).  This function is used to keep track of the minimum and 
maximum pressure observed in a system over a period of time or to monitor 
if a pressure min/max limit has been exceeded.. 
FREEZE 
Captures and displays the pressure measured by the active range of RPM4 
when the [ENT] key is pressed (see Section 3.3.6.6).  This function is useful 
to record the pressure present at the time of an operator observed trigger 
event, for example when the needle of an analog gauge is on the nominal 
point or when a switch activates. 
CLEAN 
Blanks out the second line of the display (see Section 3.3.6.7).  This function 
is used when a simple display of pressure measured by the RPM4 active 
range with minimal additional information is desired.