MKS Stabil-Ion 370 Series, Инструкция по эксплуатации, Страница: 67 / 122

4 Preparing the Stabil-Ion System for Operation
4-9
Series 370 Stabil-Ion Instruction Manual - 370119
4.3.3.3 Gauge Scale Factor
SCALE FACTOR: The scale factor is normally set to 1.000. This will cause the display to read
correctly when the gas in the system matches the gas of the calibration memory. Scale factor
adjustment is provided so that the display can be made to read approximately correct for other
gases when using the N
2
memory. See Table 4-4, Scale Factors, for other gases.
If highly accurate measurement of pressure of gases is required, we recommend calibration for the
specific gas and system to be used. See Section 4.2 on page 4-1. The standard calibration is for N
2
.
If the calibration memory is changed to match the gas in the system, the correct scale factor setting
is 1.000.
Different gases have different ionization probabilities. If a Stabil-Ion Gauge and Controller are
calibrated for N
2
, and if argon is the predominant gas in the system, setting the scale factor at
7.75 x 10
-1
as shown in Table 4-4 causes the pressure indications for N
2
to be multiplied by
0.775, thus providing correct pressure indications for argon over most of the pressure range. At
pressures above 1 x 10
-5
Torr this method may not provide accurate pressure indications.
(Do not use these scale factors for CONVECTRON Gauges)
To prepare for measuring the pressure of gases other than air or N
2
with IG1 or IG2, proceed as
follows:
(The default factory setting for this function is 1.000.)
1. If a Memory Module is used for an alternate gas see Section 4.3.2 on page 4-5 for loading and
leave the Scale Factor at 1.00.
2. Open the front panel door and locate the electrometer module and LCD display.
3. Press the
▼
arrow key until you see the control menu in the display.
Table 4-4 Scale Factors for Use with Ionization Gauges
Gas Scale Factor Gas Scale Factor
He 5.56 H
2
0 8.93 x 10
-1
Ne 3.33 NO 8.62 x 10
-1
D
2
2.86 Ar 7.75 x 10
-1
H
2
2.17 CO
2
7.04 x 10
-1
N
2
1.00 Kr 5.15 x 10
-1
Air 1.00 SF 4.00 x 10
-1
O
2
9.90 x 10
-1
Xe 3.48 x 10
-1
CO 9.52 x 10
-1
Hg 2.75 x 10
-1
Control
Menu