Shut Down Procedure; Setting Test Parameters - Veeco MS40 Operation And Maintenance Manual

2.6
The MS-40 may be shut down at any time by pressing the on/off (I/O) switch
to the off (O) position. The unit automatically ensures that the vacuum system
and system electronics are properly powered down. Turn off all peripheral
equipment (i.e., external rough pump, printer, etc.).
2.7
This section describes the testing parameters that may be modified by the
user before and during actual leak testing, the function of the parameters
and exactly how they may be adjusted. For most of the following test
parameters, the factory default settings will be more than sufficient.
However, specific tests may eventually require changes in these settings in
order to optimally match any unique requirements of the test object.
The adjustable test parameters consist of various methods for the selection
and timing of the opening and closing of the MS-40 s vacuum system valves
(as controlled by the system computer). The purpose of these timing
adjustments and their settings are explained below. Please also refer to
Chapter 3, Theory of Operation for further information.
Setting Crossover 1
The MS-40 has two specific and important set points while leak testing.
During testing, as the unit ranges downward, different testing modes are
required. Crossover 1 is defined as the set point (the point during pump
down) where the unit switches from its "Gross Mode Testing" to "Reverse
Mode Testing". All Gross Mode testing is performed in conjunction with
the optional external pump. When using an external pump, the unit
determines that the leak is smaller than a "gross" leak, the external
roughing valve is closed and the unit's testing mode "crosses over" into
reverse flow testing. When the unit is used without an external pump,
"cross over" is the point when roughing of the test object ends and reverse
mode testing begins.
To reset the Crossover 1 parameter:
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Shut Down Procedure

Setting Test Parameters

1 Press the SELECT arrow keys until the green indicator next
to Crossover 1 is lit.
2 The Service Panel alphanumeric display will display a number
up to 9,600 indicating the crossover set point in millitorr.
2-25