INFICON Helium Leak Detector Modul1000 - Manual (Page 70)

6-29
Operation
jinb
80
e1
-h
Op
er
at
in
g M
a
nua
l
(1
01
2)
→
Contamination protection
If this mode is switched on, the Modul1000 closes all valves as soon as the measured
leak rate exceeds the value limited by the contamination protection. Thus no more
Helium gets into the mass spectrometer. Helium contamination of the leak detector
will be avoided.
→
Pressure limit for vacuum area
In this menu, the factory-set switching point from evacuation to measurement mode
ULTRA can be programmed. This can be necessary when the Modul1000 shall evac-
uate other gases than air. The pressure signal of the gas-type-depending Inlet pres-
sure indication (Pirani) can then provide other values to the process control for
switching over. This can be adjusted by changing the switching points.
Default setting: 0.4 mbar (Modul1000) or 3 mbar (Modul1000b)
→
Pressure limit for Sniff mode
This function is automatically activated in sniff mode. The pressure limits define an
upper and lower limit of the inlet pressure. If the pressure is not in this range, the
following error messages/warnings will be generated:
Fore-vacuum pressure > Maximum pressure: Error message E63 (Capillaries defec-
tive)
Fore-vacuum pressure > Minimum pressure: Warning W62 (Gas flow through capil-
laries too low).
→
Maximum Evacuation time
This menu item is used to define when the gross leak message is to occur. The gross
leak detection process operates in two steps and the limits can be adapted as
required.
This menu item is particularly useful in series testing under the same conditions at
all times.
After pressing the start button the test sample is evacuated.
If the required pressure conditions are not achieved within the time to be set here, or
they are not below the set values (p1< 100 mbar or p1 < pressure limit for vacuum
areas), the evacuation process will be interrupted and a warning message will
appear on the display. (W75 or W76)
On the one hand, the selected periods depend on the desired reaction time for the
gross leak message, and on the other hand, they depend on the volume of the test
sample and the effective pumping speed.
If the evacuation time was set to endless, the oil level of the rotary vane pump should
be checked more frequently.