Model 979 Series Helium Mass Spectrometer Leak Detector
DRAFT 9/15/03
2-19
2.6.4 Rough Pump Set-Up
Touch the ROUGH PUMP SET-UP box to display the Rough Pump Set-Up screen
(Figure 2-11), which provides the end user with the ability to select the function of the dedi-
cated rough pump on a dual pump system. The dual pump version of the 979 can be con-
figured so that the dedicated rough pump is connected to the test port only during the
roughing cycle, or so that it is connected to the test port during the rough and test cycles.
Figure 2-11
Rough Pump Set-Up Screen
2.6.4.1 Selecting Rough Only or Split Flow Mode
The first toggle box in the Rough Pump Set-Up screen is used to select the function of the
dedicated rough pump: ROUGH ONLY, SPLIT FLOW, and NOT INSTALLED.
ROUGH ONLY
In ROUGH ONLY mode, the dedicated roughing pump pumps on
the test port only during the roughing phase of the test cycle. Once
the test object reaches the tolerable test transfer pressure, the
roughing valve closes and the dedicated rough pump is isolated
from the test object.
SPLIT FLOW
In SPLIT FLOW mode, the dedicated rough pump continues to
pump on the test object after the tolerable test transfer pressure has
been achieved. Split flow testing provides additional pumping
capacity on the test object during the test cycle. Use this mode for
systems with potentially high gas load or net volumes greater than a
few liters. In SPLIT FLOW MODE a test port cap must be in place
(isolating the test port) while performing an autocalibration routine
to the optional internal calibrated leak.
NOT INSTALLED
Always select this mode for single mechanical pump systems.
To change the rough pump operation, the system must be in VENT mode and the front panel
key switch in the SET-UP or SERVICE position.
DONE
ROUGH PUMP SET-UP
ROUGH ONLY
ROUGH PUMP SIZE 400 LPM
FORE PUMP SIZE 300 LPM
BACK
LEAK RATE
OUTPUT
CAL
TRANSFER
LEAK
SET-UP
REJECT &
AUDIO SET
POINTS
AUTO
SEQUENCER
SET-UP
RANGING
SET-UP
CONTROL
SET-UP
NEXT
POINTS
SET-UP
ROUGH
PUMP
SET-UP
Summary of Contents for 979 Series
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