Thyracont VSH87D, Operating Instructions Manual, Page: 55 / 64

55
Filament Control (FC)
The Bayard Alpert hot cathode sensor of the VSH is equipped with two heating
filaments. This parameter defines in which manner these filaments will be used:
»0«: filament 1 active, in case of a defect the sensor will switch to filament 2
(default)
»1«: only filament 1 will be used
»2«: only filament 2 will be used
»3«: filaments 1 and 2 will be used alternately. I.e. when the hot cathode
sensor is switched off the other filament will be activated at restart of
the sensor.
Filament Number (FN)
With this parameter you can check whether filament 1 or 2 of the hot cathode sen-
sor is currently activated.
Filament Status (FS)
This parameter is used to check the failure status of the hot cathode sensor:
»0«: no error, filaments 1 and 2 ok
»1«: filament 1 defective
»2«: filament 2 defective
»3«: filaments 1 and 2 defective
Gas Correction Factor (C1 / C3)
The measurement signal of the VSH depends on type and composition of the gas
being measured. The unit is adjusted for N
2
and dry air. For other gases the pres-
sure display can be corrected below 0.1 mbar by setting correction factors for both
sensor types.
The measurement results of each sensor are then individually multiplied with the
corresponding correction factors by the unit’s microcontroller, thereby providing a
corrected pressure reading as analog and digital output.
Value range: 0.20 ... 8.0
Correction factor C1 Pirani:
Ar
CO CO
2
H
2
He N
2
Ne Kr
1.6 1.0 0.89 0.57 1.0 1.0 1.4 2.4
Correction factor C3 hot cathode:
Ar
CO
2
H
2
He N
2
Ne Kr Xe
0.8 0.74 2.4 5.9 1.0 3.5 0.6 0.41
VSH-RS485-200116