Series 360, Granville-Phillips, Stabil-Ion, Ionization, Vacuum ...

4 Preparing the Stabil-Ion System for Operation
RS-232
ELECTROMETER
CONVECTRON
PROCESS CONTROL
IG-1 AUTO
Off SP On
Data Port
IG1 IG2 Scale
Factor
Adjust
Pressure
Range
L
H L
H
Cathode
1
2 1 2
IG1 IG2
OFF
SET
ATM
VAC
IG-2 AUTO
OFF
SET
ATM
VAC
1
2
3
4
5
6
3
▲
Set
▲
C
H
A
N
N
E
L
IG1
O
Degas
O
IG2
O
On
O
Remote
Figure 4-1
Control Unit (with Door Open) Showing Electrometer Module Controls.
a. SCALE FACTOR: Assuming the gas in the system is air or N 2 , adjust IG1 and IG2 scale
factors to 1.00 with the scale factor switch set in the respective positions. Then set the
scale factor switch at OFF. See Section 4.1.2 on page 4-3 for other gases.
b. CATHODE: Set at 1 for primary cathode (set at 2 for alternate cathode if required).
Separate switches are provided for IG1 and IG2.
c. PRESSURE RANGE: Select H or L. Separate switches are provided for IG1 and IG2.
The H range is preferred for applications involving pressure measurement above 1x10 -4 Torr.
The emission current and cathode power are reduced and the upper pressure limit and
overpressure IG shut down setpoint are extended. The H range provides increased cathode life
when the IG is operated at higher pressures.
The L range is preferred for applications involving pressure measurement below approximately
1x10 -7 Torr. It provides the fastest response to pressures below 1x10 -7 Torr and allows
measurement to the x-ray limit of the Stabil-Ion Gauge.
Whether H or L is preferred between 10 -4 and 10 -7 Torr depends on whether the expected
pressures will be above 10 -4 Torr or below 10 -7 Torr.
The Stabil-Ion Gauge will provide the best stability and lifetime when the pressure range
selector switch is set as shown in Table 4-1.
4-2
Series 360 Stabil-Ion December, 2001