System control: Vacuum system
2-10
User Manual
C O N F I D E N T I A L –
limited rights
Feb 2018
Revision A
Vacuum status
The vacuum status controls are in the
Vacuum
module. The
Pump
button starts pumping the chamber for the operating pressure
and the
Vent
button starts venting the chamber for a sample
exchange.
At the bottom right side of the status bar the actual vacuum
status is represented by the colored icon, which may have three
possible colors with the following meanings:
•
Green: PUMPED
to a desired vacuum mode
•
Orange: TRANSITION
between vacuum modes
(pumping / venting / purging)
•
Gray: VENTED
to atmospheric pressure
Pump button
When the
Pump
button is clicked and the status is
Vented
or when changing the vacuum mode, the system starts to
pump. The target pressure depends on the selected vacuum mode. The Pump button is highlighted and is not
accessible.
For
High Vacuum
, the system achieves the lowest pressure possible. For
Low Vacuum
, it achieves the pressure
specified in the
Vacuum
module /
Chamber Pressure
adjuster. The purge function can be defined in the
Preferences…
dialogue /
Low Vacuum
tab (see Chapter 3).
When the
Pump
button is clicked and the status is
Transition
(venting), the venting procedure stops and the system
immediately starts to pump to the actually selected vacuum mode.
Vent button
When the
Vent
button is clicked and the status is
Pumped
, the
confirmation dialog appears. After confirmation, the system
switches off the detector voltages, high voltage supplies, vacuum
pumps and uses the appropriate valves to vent the system with
the use of the dry nitrogen brought to the
Nitrogen Inlet
. Nitrogen
is recommended to obtain a better vacuum for high resolution
imaging in HiVac mode.
The
Sample Exchange
window and progress bar are shown; the
Vent button is highlighted but not accessible. After a specified venting time, the venting valve closes and the
vacuum status
should indicate
Vented
(see
Preferences…
dialogue /
General
tab /
Venting valve opening time
item).
The chamber door can be opened and the button is again enabled.
When the
Vent
button is clicked and the status is
Transition
(pumping), this dialog appears. After confirmation, the
pumping procedure stops and the venting procedure starts.
When the
Vent
button is clicked and the status is
Vented
, this dialog appears. After confirmation, the venting valves
re-open for the specified venting time and then the valves close.
Note
If you vent the system in order to change a detector, wait until the icon with a gray specimen chamber appears in the Status
module. Otherwise there is a risk of a detector assessment malfunction, and as a result, the PLA will not be known by the
system.
