Molbloc-S Operation - Fluke MOLBOX RFM Operation And Maintenance Manual

molbox™ RFM™ OPERATION AND MAINTENANCE MANUAL
molbox RFM has a SCREEN SAVER function that causes the display to dim if NO key is
pressed for 10 minutes. Pressing a key restores full power to the display. The screen
saver activation time can be changed or screen saving can be completely suppressed (see
Section 3.6.5.1).
3.2.2

molbloc-S OPERATION

As with molbloc-L there are limits on some of the conditions that may exist if the user expects
to make accurate flow measurements with molbloc-S. The key condition that can be monitored is
the back pressure ratio, or BPR, which determines whether critical flow through the molbloc
is achieved (see Section 3.1.2).
When the BPR is in a "safe" region for critical flow measurements, the appearance of the
MAIN run screen is identical to the MAIN run screen for molbloc-L operation (see Section
3.2.1). When the molbox RFM BPR limit is exceeded, there are two possible MAIN run
screen indicators.
exceeded. In this condition, the flow may not be critical and flow measurements should not
be relied on to meet specifications. When the BPR limit is exceeded by a large margin, the
flow is almost certainly not critical and the calculated value may be nonsensical,
so the flow value is not shown and is replaced by <BPR HI>.
When molbloc-S is in the BPR OFF mode (see Section 3.6.9), BPR is not monitored and
invalid flow values may be displayed in the molbloc-S MAIN run screen with no indication
that a the BPR value is high.
1. <*> Ready/Not Ready indication; <*> when Ready <↑>
(increasing) or <↓> (decreasing) indicating direction of flow
rate evolution when Not Ready; <P> when BPR is higher
than choking limit. (see Section 3.1.2).
2. <FLOWWW>:
measured by molbox RFM. Result of last flow averaging
cycle if in AVERAGE display (see Section 3.4.6.2). Flashes
if BPR is higher than the choking limit. If BPR exceeds the
choking limit by a large margin, <BPR HI> replaces the flow
value.
3. <UNIT>
4. <k>: Same as molbloc-L (see Section 3.4.1).
5. <GGGG>: Indicates the current molbox gas selection (see Section 3.4.2). This should be the gas that is
flowing through the molbloc. <AirW> indicates that air is selected and a humidity correction is being applied
(see Section 3.4.2.2).
6. <D>: Same as molbloc-L (see Section 3.4.6).
7.
<DISPLAY MODE DATA>: Information displayed depends on current display mode (see Section 3.4.6).
When a number is too large to show in the allocated display space, molbox RFM
displays <********>.
molbox RFM has a SCREEN SAVER function that causes the display to dim if NO key is
pressed for 10 minutes. Pressing a key restores full power to the display. The screen
saver activation time can be changed or screen saving can be completely suppressed (see
Section 3.6.5.1).
© 1998-2007 DH Instruments, a Fluke Company
A flashing flow value and unit indicate that the BPR limit has been
Numerical value and sign of the flow
Current flow unit of measure (see Section 3.4.3). Flashes if BPR is higher than the choking limit.
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*FLOWWW unitk GGGG
D DISPLAY MODE DATA