Analog Output - Instrutech Hornet User Manual

Instruction Manual
7

Analog Output

A) The log-linear output signal and pressure are related by the
following formulas when units of measurement is in Torr and
mbar:
(volts – 10)
P= 10 V= log
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:
(volts - 8)
P= 10 V= log
Where P is the pressure in Pascals, and V is the output signal in
volts.
The output voltage is zero when pressure is at 1.0E-10 Torr.
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) The pressure exceeds 5.0 x 10
The following chart shows the graphical results of table and formulas above. Pressure is plotted on the X-axis with a log
scale; the output signal is plotted on the Y-axis on a linear scale.
10.0
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
1.0E-10 1.0E-09 1.0E-08
InstruTech, Inc.
(P) + 10
10
(P) + 8
10
-3
Torr at 4 ma emission current.
-2
Torr at 100 µA emission current.
Log-Linear Analog Voltage to Pressure
1.0E-07 1.0E-06 1.0E-05
Pressure (Torr)
Log-Linear Analog Output
Pressure (Torr)
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
5.0E-02
See Notes
1.0E-04 1.0E-03 1.0E-02
IGM401 Hornet
Voltage
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
8.698
>10
>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.
1.0E-01 1.0E+00
Page 30