Model 979 Series Helium Mass Spectrometer Leak Detector
1-14
DRAFT 9/15/03
Under
The UNDER range light indicates that the measured helium leak
rate is currently less than the minimum displayable value. The light
may flash briefly as the system recovers from a leak indication and
the displayable leak rate approaches zero. If the AUTO-ZERO < 0
is turned on, the UNDER light may also flash briefly as the system
resets the zero point to a lower value. Refer to Section 3.1.1.1
“AUTO-ZERO < 0” on page 3-3.
The 979 does not display a leak rate while the UNDER light is on.
If this light stays on for more than a few seconds, recalibrate the
system to set operating parameters to the correct zero value. This
situation can take place if the 979 was not fully warmed up before
calibration was initiated.
Over
The OVER range light indicates that the system is saturated with
helium and the measured leak rate is higher than the maximum
displayable value.
1.8 Rear Panel Controls
1.8.1 System Control and Communication Panel
The system control and communication panel (Figure 1-9) is located on the lower left
section of the rear panel.
Figure 1-9
System Control and Communication Panel
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12
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➁
➂
➃
➄
➅
Summary of Contents for 979 Series
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