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vd84-201113
5.5 Gas Correction Factor
The pressure reading of your VD84 depends on type and composition of the gas
being measured. The device is adjusted for N
2
and dry air, for He and CO the de-
viation can be neglected below 0.5 mbar. For other gases a correction factor can
be set which 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 sec-
onds. 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!
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