Varian 979 Series, Руководство по эксплуатации

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Model 979 Series Helium Mass Spectrometer Leak Detector
DRAFT 9/15/03
2-5
2.2.1 Sniffer Set-Up Procedure
1. Vent the 979 and insert a Vacuum Technologies Power Probe
(Part Number K9565306) into the test port. Refer to the product catalog for additional
Power Probe configurations.
2. Set Range Stop to 10 - 07 (See Figure 2-12 on page 2-20).
3. Monitor the test port pressure reading on the touch panel display and adjust the Power
Probe flow valve for a test port pressure of 1 to 2 Torr.
4. Press ZERO to suppress the helium background signal.
Table 2-1 shows sniffer mode sensitivity.
All values in this table are at test port pressures between 1 and 2 Torr.
2.2.2 Key Switch
The 979 Key Switch allows three different levels of access to the touch panel system
controls—RUN, SET-UP or SERVICE. Two different keys are provided with the leak detector:
❑
Key T008 operates the switch in either the RUN or SET-UP positions.
The T008 key is intended for use by a line supervisor or engineer and allows most
parameters to be changed, but does not allow any operation that could damage the
unit.
❑
Key T009 operates the switch in RUN, SET-UP or SERVICE positions.
The T009 key is intended for service personnel and those who are very familiar with
the operation of the unit. Operations such as manually changing the valves can only
be performed when the key switch is in the SERVICE position. A first-level operator
would not have a key and would be able to operate the 979 with the key switch in
the RUN position only (key removed). No changes to the operating parameters are
allowed when the key switch is in the RUN position.
Table 2-1 Sniffer Mode Sensitivity Range (Full Scale)
Standard Sensitivity High Sensitivity
10
−
4
to 10
−
7
10
−
5
to 10
−
8