6 Operation
Once the supply voltage has been established, the measuring signal is available at the electrical con-
nection between pins 2 and 3.
Recommendations
► Respect the minimum stabilization period of 10 minutes.
► Respect the relation between measuring signal and pressure.
► Leave the gauge switched on at all times, regardless of the prevalent pressure.
6.1 Operating modes
The identification output shows the respective operating status of the gauge. As long as the cold cath-
ode measurement system has not ignited, the signal output issues the Pirani measured value only. (If p
< 5 × 10
-4
hPa: display "Pirani-Underrange").
Pressure
LED
Operations mode
Identification
p > 1 × 10
-2
hPa Off
Pirani operation
11.1 kΩ (Pirani)
p < 1 × 10
-2
hPa lights up Pirani operation (cold cathode measuring sys-
tem not ignited)
11.1 kΩ (Pirani)
Combined operation
9.1 kΩ (combination)
Tbl. 5:
Operating modes
6.2 Converting measuring signal and pressure
1E+04
1E+02
1E+00
0.0 0.5
1.5
2.5
3.5
4.5
5.5
6.5
7.5
8.5
9.5
10.5
1E–02
1E–04
1E–06
1E–08
o
ve
rra
n
g
e
Pa
hPa
torr
se
n
so
r
e
rro
r
p
U [V]
se
n
so
r
e
rro
r
u
n
d
e
rra
n
g
e
o
ve
rra
n
g
e
Fig. 7:
Relation between measuring signal and pressure
p Pressure
U
Measuring signal [V] (output voltage)
Operation
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