4. OPERATION
Page 63 © 2005 DH Instruments, Inc.
the requested pressure has been set and stabilized, a Ready indication is given (see Section
4.1.1) and the actual value of the set pressure is displayed in
the <Pressure> field. In most
cases, the final set pressure is not exactly equal to the target pressure (see Section 4.1.4).
4.2.4.1 SETTING ZERO PRESSURE
Setting zero in absolute measurement mode
In absolute measurement mode, entering a target pressure of zero transitions the
active pressure standard to the FPG8601 if it is not already active, controls down
using the FPG’s PPC3 pressure controller to the pressure defined in [Setup],
[Configuration], [Limits] and then opens the FPG bypass valve (see
Figure 29).
This causes the pressure on the FPG8601 and at the ADCS-601 TEST(+)
port, to
be pulled down as low as possible directly by the reference vacuum pump system.
The pressure achieved is indicated in the ADCS Control Panel <Pressure> field.
Ready is indicated when the FPG8601 stability criterion is reached.
Setting zero in gauge measurement mode
The result of entering zero as the target pressure in gauge measurement mode
depends upon a [Maintenance], [FPG Cal Options] selection (see Section
4.3.2).
If the <Vent using
the FPG in gauge measurement mode> option IS NOT
selected, the active pressure standard is transitioned to PG7601 if it is not already
active and the PG7601’s PPC3 controller vents to atmosphere setting zero gauge
pressure. The ADCS Control Panel <Pressure> field is fixed to <0.000>. This is the
default setting.
If the <Vent using the FPG in gauge measurement mode> option IS selected, the
active pressure standard is transitioned to FPG8601 if it is not already active and the
FPG8601’s PPC3 controller vents to atmosphere setting zero gauge pressure.
The ADCS Control Panel <Pressure> field indicates the reading of the FPG8601.
4.2.4.2 SETTING IDLE STATUS
This section describes the ADCS-601 idle condition. The system can be left
in this condition indefinitely but the system must remain powered ON and
supplied with pressure and vacuum. See Section 3.7 for information on
ADCS-601 system short and long term shut down procedures.
In the normal idle (resting) condition of the ADCS-601 system, the pressure
applied to the TEST(+) port is vented. This can be accomplished by pressing the
ADCS Run Screen Toolbar [VENT] button (see Section
4.3.5.3) or setting a
target pressure of zero in gauge measurement mode (see Section 4.2.4.1).
When vented in absolute mode, the ADCS Control Panel <Pressure> field
indicat
es < --- VENT --- > and the pressure is Ready. When vented in gauge
mode, the <Pressure> field indicates <0.000> and the pressure is Ready.
4.2.5 PRESSURE EXERCISING THE DEVICE UNDER TEST
Many devices require pressure exercising prior to validation or calibration. Generally, their
exercising can be performed quickly and without precise knowledge of the endpoint pressures.
ADCS-601 supports a function to allow simple, rapid exercising of the DUT. The exercise
function uses the PG7601’s pressure controller alone rather than the pressure standards.
To run an exercise routine, press the [Exercise Pressure] button on the ADCS Run Screen
Toolbar (see Section
4.3.5.3). Then fill in the form to define the desired exercise routine
(see Figure 30).
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