3/5
Detector operation
Alcatel - High Vacuum Technology - ASM 180 TD/TD+ - ASM 181 TD+ User’s Manual
Edition 04 - September 97
Connect the
probe to the quick
connector.
The filament emission goes off for a few seconds during the
probe roughing phase.
The test is operational
when the emission
presence indicator light
is lit.
The sniffer test mode indicator light
is lit on the unit.
The measured helium flow signal is
shown on the gross leak
measurement display.
When the LDS probe is placed in
the ambient air, the He signal
displayed is approximately
5.10
-6
to 1.10
-5
(equivalent to the
natural concentration of helium in
the air).
Check that the helium signal
decreases when the probe hole is
blocked with your finger.
Given the detector configuration, the measured flow
corresponds to the helium concentration.
e.g.: Display of 5.10
-6
corresponds to a measured leak of
5.10
-6
mbar.l/s of He. and to a measured He concentration
of 5.10
-6
or 5ppm.
The inlet pressure displayed on the remote control unit does
not affect operation (it is an independent circuit: see
A 20
).
The cycle key is not used.
Select the LDS
function.
Check the probe operation
Measured flow = concentration
LDS mode specificities
C 20
Working in Sniffer
mode (LDS)
ASM 180 Compact version
ASM 181 Console version