ADCS-601-AF™ OPERATION AND MAINTENANCE MANUAL
© 2005 - 2007 DH Instruments, a Fluke Company
Page 62
4.2.3
CHANGING MEASUREMENT MODE (ABSOLUTE, GAUGE)
There is a well defined order of operation for transitioning the ADCS-601-AF system
between measurement modes. The order is controlled by the ADCS Tools software. Mode
transitions should only be performed under ADCS Tools control. Vacuum pumps must
always be left ON in absolute mode. Before turning OFF vacuum pumps or disconnecting
vacuum supplies, transition to gauge mode.
The current ADCS-601-AF measurement mode is indicated by:
- <a> (absolute) or <g> (gauge> following the pressure unit of measure in the ADCS
Control Panel <Pressure> field (see Section 4.3.5.1).
- The color of the pressure standard reference pressure circuit and PG7601 bell jar in the
ADCS System Display. light blue = gauge mode (atmospheric reference), black = absolute
mode (vacuum reference) (see Section 4.3.5.2).
- The value displayed in the ADCS Run Screen Control Panel <Reference Vacuum> field.
<N/A>= gauge mode; numerical value = absolute mode (see Section 4.3.5.1).
The complete ADCS-601-AF system is always in either absolute or gauge measurement
mode. Target pressure requests are interpreted and set in the active measurement mode. In
absolute mode the ADCS-601-AF pressure standard reference pressure circuit is pulled
down to vacuum by the reference vacuum system. In gauge mode, the reference pressure
circuit is open to atmospheric pressure.
To change the ADCS-601-AF measurement mode from gauge to absolute or absolute to gauge,
press the down arrow next to the
[MEASUREMENT MODE]
button on the
ADCS Main Run
Screen Toolbar
(see Section 4.3.5.3). The
ADCS Main Run Screen
<Pressure>
field displays
< ---Measurement Mode Transition--- >
while the ADCS-601-AF system makes the changes
necessary to change measurement modes. Do not attempt any other operations until the
measurement mode transition is complete, as indicated by the
<Pressure>
field no longer
indicating
< ---Measurement Mode Transition--- >
and the
Status Bar
(see Section 4.3.4) no
longer indicating transition activities. This process may require several minutes to complete.
After a measurement mode change, the ADCS pressure (pressure on
TEST(+)
port) is
always vented to atmosphere.
Pressing the
[MEASUREMENT MODE]
button itself, rather than the down arrow next to it, is
used to reset the current measurement mode.
4.2.4
SETTING PRESSURES
Before setting a pressure, be sure that the TEST(+) port is not open to atmosphere or
connected to a system with a very large leak. Execution of certain pressure requests could
damage the ADCS-601-AF system if the TEST(+) port is open. If nothing is connected to the
TEST(+) port, it must be plugged with the plug quick connect stem provided.
To set a pressure with ADCS-601-AF, first verify that ADCS-601-AF is in the desired
measurement mode (gauge or absolute) (see Section 4.2.3) and that the
TEST(+)
port is not
open to atmosphere. If nothing is connected to the
TEST(+)
port, it should be plugged with
the plug quick connector stem provided.
Enter the desired target pressure in the
ADCS Control Panel
<Target Pressure>
field and
press
[ENTER]
on the system controller (PC). Observe the
ADCS Status Bar
and
System
Display
for information on progress in setting the requested pressure (see Section4.3.1). When
