Model 979 Series Helium Mass Spectrometer Leak Detector
2-2
DRAFT 9/15/03
2.2 Operator Interface
The front panel of the Model 979 is shown in Figure 2-1. Operation controls include
buttons for AUDIO VOLUME, SNIFFER, ZERO, READ STANDARD LEAK, CALIBRATE,
TEST, HOLD and VENT functions. In addition to the basic control buttons, the 979 utilizes a
touch panel display for the initial set-up of the leak detector. An access key switch is also
provided to prevent unauthorized changes to the system set-up variables.
Figure 2-1
979 Front Panel
Press the TEST/HOLD button when in VENT mode to automatically advance the
979 through roughing and then into the test state. The optimum sampling mode
is automatically selected, depending on the system configuration and set-up,
and the achievable test port pressure and leak rate. The TEST indicator LED,
located above TEST, illuminates when the 979 is in a test state.
If the TEST/HOLD button is pressed while the 979 is in the test state, the unit
advances to the HOLD state and the HOLD indicator LED, located below
HOLD, illuminates. When in HOLD mode, the test port valve V6 is closed,
isolating the test port and any test objects or fixturing from the leak detector
vacuum system. The test port pressure gauge is located on the test port side of
V6 and subsequently a rise in test pressure may be observed while in this mode.
While in TEST or HOLD, pressing the TEST/HOLD button causes the machine to
alternate between the two states.
Press the VENT button to isolate the test port from the leak detector vacuum
system and vent the test port to the atmosphere. The VENT indicator LED,
located above VENT, remains lit while the 979 is in the vented state.
Summary of Contents for 979 Series
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