Inficon 550-300A, Operating Manual

Page: 39 / 128

Working Modes
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Helium filling station
The helium filling station consists of a vacuum pump, the valves V30- V34, a pres-
sure gauge and the helium supply unit.
Valves V30, V31, V32, V33, V34
The test run of the Commander software includes the control of all valves necessary
for the helium filling procedure of the test sample. The valves are controlled via the
„VALVES“ connection.
Notice:
We recommend using pressure activated valves.
Pressure gauge
The test sample is filled with helium and the gross leak test are pressure controlled
and therefore, they need a pressure gauge which has a measuring range of <
50 mbar reaching to the maximum filling pressure of the test sample. The character-
istics and the measuring range of the used measuring point can be set on the
Modul1000. The pressure gauge is connected to the „PRESSURE GAUGE“ terminal
on the right side of the device.
Vacuum pump
The vacuum pump evacuates the test sample before it is filled with helium to remove
the air from the part as well as possible. We recommend using a pump with a final
pressure of < 50 mbar.
5.4.2 Test sequence of events
1
The test sample is in the vacuum chamber which is connected to the inlet of
Modul1000. The unit under test is in the vacuum chamber which is connected to the
inlet of Modul1000.
2
After the START signal, the Modul1000 starts evacuating the vacuum chamber. If a
partial flow pump is connected with Modul1000, the partial flow valve V20 ( Fig. 5-1 )
will be actuated and the test run is accordingly supported by the partial flow pump.
3 Before the actual helium test is executed, a gross leak test is carries out, to detect
gross leaks in the test sample or in the leak detector. When a chamber pressure of
100 mbar is reached, it will be checked, whether the pressure of the test sample has
dropped and is lower than the set pressure p_A_ for the gross leak test. If this is the
case, the measuring cycle will be interrupted indicating the error message 91.
4 If the system passes the gross leak test, valve V30 will be opened and the test
sample will be evacuated. If the systems passes the gross leak test, the valve V30
will open and the test sample will be evacuated. Otherwise, the measuring cycle will
be interrupted indicating the error message 92.
5 If the chamber pressure drops within the set time t_F_Readiness_for_measurement
down to the change-over pressure, the device will switch over to Measuring mode.
This change-over pressure can be set in the following menu:
Main menu --> Settings --> Monitoring --> Pressure limits for vacuum areas"
between 0.2 mbar and 0.4 mbar.
Depending on the settings in "Background suppression", an automatic background
subtraction will be carried out, if necessary: