Oerlikon THERMOVAC TM101 Operating Instructions Manual - page 18
18
300306186_002_A2 - 12/2010 - © Oerlikon Leybold Vacuum
5.5 Gas Correction Factor
The output signal of the Pirani sensor inside your TM 101 and therefore the
pressure reading of the gauge below 15 mbar depend on type and composition
of the gas being measured. The device is adjusted for N
2
and dry air, for He and
CO the deviation can be neglected below 0.5 mbar. For other gases a correction
factor can be set which affects pressure reading below 15 mbar and produces
correct readings below 0.5 mbar. The measurements of the Pirani sensor are
hereby multiplied with the correction factor.
Correction factor Pirani:
Ar
1,6
CO
2
0,89
He
1,0
Ne
1,4
CO
1,0
H
2
0,57
N
2
1,0
Kr
2,4
To adjust the gas correction factor, switch the unit into Configuration Mode. For
this the instrument must be switched-off. Hold the Mode-Key pressed then, until
the display shows "rAtE".
Then press Mode-Key several times, until the display shows "corr":
After 5 more seconds the current factor setting is displayed:
The setting range is 0.20 to 8.00.
The value can now be incremented by means
of the Mode-Key. If you hold the key pressed
the value counts up automatically to 8.00 and
then restarts at 0.20.
Without further keystroke, the unit switches to Auto-Off Mode after approx. 5
seconds. The last setting of the gas correction factor is saved.
If a correction factor different from 1,00 is
set, symbol "S1" is shown at the lower
boundary of the display!
5s
MODE
MODE
mbar
S1