© Agilent Technologies 1989–2002 Agilent 3070 / 79000 Site Preparation 7-9
Chapter 7: Site Preparation – Compressed Air and Vacuum Requirements: Vacuum Requirements
Vacuum Guidelines
Keep these additional guidelines in mind as you design
your system:
CAUTION
✸
Vacuum pumps installed for the tester should be
installed outside or vented outside in order to
prevent the vacuum pump from exhausting
oil-bearing air or carbon fragments in areas where
there are people.
â– Use the largest diameter of pipe practical from the
vacuum pump to the testhead area. This
diminishes vacuum loss due to friction in the
piping (especially at bends), and provides a
demand reservoir.
â– Agilent also recommends that a filter be installed
between the vacuum supply and the testhead to
prevent dirt or contaminants from being sucked
through the test fixture into the vacuum supply.
Vacuum Examples
This section shows some of the vacuum control schemes
possible for the 3070. The pressure meters, flow meter,
and filter in these examples are optional but
recommended.
If the vacuum manifold is used, a 2-inch vacuum hose
should be used. If vacuum ports are connected
individually, a 1-inch vacuum hose must be used.
Figure 7-5 on page 7-10 is a schematic representation
of a two-module 307X system with one vacuum control
output used to control both vacuum ports 2 and 3. The
vacuum control solenoid is shown to be one of the
air-piloted types, thus the compressed air line to the
device.
Figure 7-6 on page 7-11 shows a four-module 307X
system with separate control of each vacuum port. This
arrangement allows each vacuum port to be actuated
separately, but this flexibility requires the expense of
four solenoid valves and filters. The size and type of
boards you test may make it unnecessary for you to
individually control the four ports. If all the boards that
you test are large and require all four modules, there is
no reason to individually control the four ports.
Figure 7-7 on page 7-12 shows a four-module 307X
system with two solenoid valves and two manual
vacuum valves.
In this example, the two solenoid valves always control
one port, but each may control a second vacuum port if a
manual valve is opened.
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