tinb29e1-c (2019-10) VGC083A_B.om 39
damage due to incorrect pressure readings and improper system control functions
as a result of incorrect pressure measurement readings may result.
[Factory default = 10.00 for BAG051 / 052 / 053]
When using the resistive or I
2
R degas nude IG (Series BAG051, or equivalent) or
glass enclosed IG (BAG052 / 053, or equivalent) set sensitivity to 10 per Torr. If
you are using an IG with a known sensitivity other than 10 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 calculation 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 resistive or I
2
R degas ionization gauges 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 VGC083B is programmed for the actual sensitivity of the head it
is used with may result in pressure readings that are not true pressure. Equipment
damage due to incorrect pressure readings and improper system control functions
as a result of incorrect pressure measurement readings may result.
[Factory default = 1.00E-03 for BAG050 / 051 / 052 / 053]
[Factory default = 5.00E-02 for BAG 055 Mini IG]
This function allows the user to set the pressure at which the gauge will turn off
when the emission current is running at 100 μA.
The overpressure shut down values are adjustable when emission current selected
is 100 μA. However with BAG050 / 051 / 052 / 053 when setting the overpressure
value at a higher pressure than 1.00E-03 Torr (1.00E-02 Torr maximum), review
your ion gauge head specifications to determine the maximum pressure your ion
gauge head is capable of measuring (BAG05x nuder /glass series heads are
capable of measuring a maximum pressure of 1.00E-03 Torr). When using the
BAG055 Mini IG this value cannot be set to a pressure higher than 5.00E-02.
With BAG050 / 051 / 052 / 053 the overpressure shut down value is factory set to
5.00E-04 Torr and 1.00E-04 Torr when emission current selected is 4 mA or 10 mA
respectively and cannot be changed by the user.
With BAG055 Mini IG the overpressure shut down value is factory set to
1.00E-03 Torr when emission current selected is 4 mA and cannot be changed by
the user.
[Factory default = 1.00E-03]
This setting allows the user to select a pressure value at which CG1 or CG2 or
alternate gauge can turn the IG filament on. This is applicable only when the gauge
is operating at 100 μA or 4 mA emission current setting (not applicable with 10 mA
emission current) or in the automatic emission current switching mode (EMISSION
SELECT = AUTO IE) and the IG CONTROL mode below is set to CG1, CG2 or
ALT GAUGE.
The IG TRIP PRES default value when using an emission current of 100 μA is
1.00E-03 Torr but it can be set to value as high as 1.00E-02 Torr with BAG050 /
051 / 052 / 053 and 5.00E-02 Torr for BAG055 Mini IG. However, when setting the
IG TRIP PRES value at a higher pressure than 1.00E-03 Torr, review your ion
gauge head specifications to determine the maximum pressure your ion gauge
head is capable of measuring (BAG05x nude/glass series heads are capable of
measuring a maximum pressure of 1.00E-03 Torr).
When using the BAG050 / 051 / 052 / 053 the user does not have the choice to
select a turn on point for the IG when the 4 mA or 10 emission current has been
selected. The IG turn on is always fixed at 5.00E-04 Torr and 1.00E-04 when the
emission current is set for 4 mA or 10 mA respectively. When using the BAG055
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