Instruction Manual IGM402 Hornet
InstruTech
Page 42
6.1
Ion gauge analog output - IG ONLY
ANALOG MODE
in
SETUP IG
menu is set to
IG ONLY.
LOG-LINEAR 0-9 Vdc, 1 V/decade (N
2
/ air only)
A) The log-linear output signal and pressure are related by the
following formulas when units of measurement is in
Torr
and
mbar:
P= 10
(volts – 10)
V= log
10
(P) + 10
Where P is the pressure in Torr or mbar, and V is the output signal
in Volts.
B) The log-linear output signal and pressure are related by the
following formulas when units of measurement is in
pascals:
P= 10
(volts - 8)
V= log
10
(P) + 8
Where P is the pressure in pascals, and V is the output signal in
Volts.
Notes - The output voltage will switch to above +10 Vdc under
the following conditions:
1) The filament is turned off or any IG fault condition.
2) The pressure exceeds 1.00 x 10
-3
Torr at 4 mA emission current.
3) The pressure exceeds 5.0 x 10
-2
Torr at 0.1 mA (100
µ
A)
emission current.
Log-Linear Analog Output (N
2
/air only)
Pressure (Torr)
Voltage
1.0E-10
0.0
1.0E-09
1.0
1.0E-08
2.0
1.0E-07
3.0
1.0E-06
4.0
1.0E-05
5.0
1.0E-04
6.0
1.0E-03
7.0
1.0E-02
8.0
5.0E-02
8.698
See Notes
>10
The following chart shows the graphical results of table and formulas above for measurements in Torr.
Pressure is plotted on the X-axis with a log scale; the output signal is plotted on the Y-axis on a linear scale.
>10 VDC
See the
conditions
listed above
which will
cause the
output to
switch to
>10VDC.
These
conditions
are listed
immediately
above this
chart on this
page.
Log-Linear Analog Voltage to Pressure
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
1.0E-10
1.0E-09
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
Pressure (Torr)
O
u
tp
u
t S
ign
al
(V
o
lt
s dc)
