Linxon LX218 - Setting Filter and ZERO

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If you use a different tracer gas for the leak detector than the one used in normal
mode later, you can use a leak rate factor to convert the measured leak rates (
4
He,
3
He or H
2
):
• into an equivalent leak rate of another gas
• into an equivalent leak rate (
4
He,
3
He or H
2
) under flow conditions other than
molecular flow
Under molecular flow conditions, the leak rate only depends on the mass of the gas.
Standby > Configuration > Test settings > Operation mode & mass
►
Adjust your settings in accordance with the table above.
As an alternative, you can change the operation mode using "Select operation mode"
in the "Standby" window.
6.4.2 Setting filter and ZERO
• The setting of the leak rate filter influences the display of the measurement results.
The recommended setting here, i.e., "Filter: dynamic", ensures that the signals are
averaged at optimized time intervals, based on the particular leak rate range. In
addition, the filter eliminates interference spikes that have nothing to do with the
leak rate signals and shows response times even at low leak rates.
• With "ZERO", you can suppress unwanted helium or hydrogen backgrounds.
When ZERO is activated, the currently measured leak rate value is interpreted as
a helium or hydrogen background and is subtracted from any subsequently
measured values.
If the background in the device is reduced, then the background value that is
suppressed by "ZERO" is automatically adjusted.
In order to activate the ZERO function, press the ZERO button on the device or on the
sniffer line briefly.
In order to deactivate the ZERO function, press and hold the ZERO button on the
device or on the sniffer line for more than 3 seconds.
The background subtraction of the mass spectrometer is set by default. Additional
information can be found in the following table:
Options Value range (min./max.) Comments
Filter Dynamic Leak rate filter with
dynamic time constant
setting
Static Leak rate filter with fixed
time constant
none No leak rate filter
ZERO Enabled Manual background
suppression activated