38 tinb29e1-c (2019-10) VGC083A_B.om
[Factory default = 1.00E-07]
The default setting is DISABLED if EMISS SELECT menu above is set to 4 mA or
100 μA. If the EMISS SELECT menu is set to AUTO IE 100-10, then the AUTO IE2
TRIP value programmed here (Factory default = 1.00E-07) allows the user to se-
lect the pressure at which emission current automatically switches from 4 mA to
10 mA. For example, if the AUTO IE2 TRIP value is set to 1.00E-07 Torr, then the
ion gauge will operate at the emission current of 4 mA from the trip pressure value
programmed for the AUTO IE1 TRIP menu above to 1.00E-07 Torr. The emission
current will then automatically switch to 10 mA at pressure of 1.00E-07 Torr or
lower. The user has the choice of programming the AUTO IE2 TRIP point any-
where between 1.00E-06 to 1.00E-08 Torr. Note that if the EMISS SELECT menu
is set to AUTO IE 100-10, then the AUTO IE1 TRIP value above must still be pro-
grammed to select the desired pressure at which emission current automatically
switches from 100 μA to 4 mA.
[Factory default = 1.00E-05]
The default setting is DISABLED if EMISS SELECT menu above is set to 4 mA or
100 μA. If the EMISS SELECT menu is set to AUTO IE 100-4, then the AUTO IE
TRIP value programmed here (Factory default = 1.00E-05) allows the user to se-
lect the pressure at which emission current automatically switches from 100 μA to
4 mA. See example in AUTO IE1 TRIP above.
[Factory default = FILAMENT 1]
Allows the user to select which filament to operate: either Filament 1 or Filament 2.
It is highly recommended to periodically alternate operating filaments 1 and 2 if the
filaments are the coated iridium type. An inactive, coated filament not operated for
an extended period of time can cause failure of that filament to establish and main-
tain emission current. This will become more problematic in applications where the
filament coating may become poisoned by process gas byproducts or materials
that have outgassed from the process materials.
[Factory default = 10 MINUTES for BAG050 / 051 / 052 / 053]
[Factory default = 2 MINUTES for BAG055 Mini IG]
The length of time, in minutes, degassing will run after it is initiated. The degas
cycle can be selected from 2 to 30 minutes in duration.
[Factory default = 25.00 for BAG050]
[Factory default = 10.00 for BAG055 - Program actual S value marked on BAG055]
When using the BAG050 nude UHV EB-degas IG or equivalent nude IG, set sensi-
tivity to 25 per Torr. When using the BAG055 Mini IG set sensitivity to the S value
marked on the BAG055 sensor. If you are using a nude IG with a known sensitivity
other than 25 per Torr, you may set the actual sensitivity for the IG head you are
using. The Sensitivity constant used by the operating system for the pressure cal-
culation is based on the following mathematical formula for the B-A ion gauge
pressure measurement:
I
c
= P × S × I
e
where P is Pressure, S is Sensitivity
1)
; I
c
is the collector current and I
e
is the
emission current.
1)
Sensitivity for the B-A type ionization gauge is a constant. A number defined as the quantity of ions
created and collected (collector current) per unit measure of pressure per the controlled quantity of
emission current from which the ion current is generated. This setting can be useful for compensating
the readout of pressure when measured by the ion gauge for gases other than nitrogen/air. Consult
reachus@inficon.com for further discussion on the use of this setting for compensated readings.
Typical sensitivity for the nude UHV EB-degas ionization gauge used is 25 per Torr (25 Torr
-1
).
Typical sensitivity for the BAG055 Mini IG used is 10 per Torr (10 Torr
-1
).
CAUTION! The user assumes all risks if the SENSITIVITY is programmed to
a value not matching the actual head (sensor) sensitivity described above. Failure
to ensure that the VGC083A is programmed for the actual sensitivity of the head it
is used with may result in pressure readings that are not true pressure. Equipment
AUTO IE2 TRIP
For BAG050 / 051 / 052 / 053
AUTO IE TRIP
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