LEYBOLD 230070V02, Руководство по эксплуатации

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22 300544652_002_C1 - 11/2016 - © Leybold
5.4
Sensor gas dependence
The PTR 90 N PENNINGVAC transmitter is based on measurement of thermal conductivity (for the MEMS Pirani-
sensor) and consequently its reading depends on gas type and gas concentration. The PTR 90 N PENNINGVAC
has calibration curves for a number of common gases. For gas setup refer to please refer to the Communication
Protocol 300544663 (RS232) and 300544664 (EtherCAT). The sensor is per factory default calibrated for Nitrogen
gas and shown below is the PTR 90 N PENNINGVAC Nitrogen MEMS Pirani reading in different gas types. Be
aware that when measuring in environments where other gases than nitrogen (calibration gas) are present, the
readings can deviate from the true pressure.
In the range below 1 mbar, the pressure indication is linear. For gases other than air, the pressure can be
determined by means of a simple conversion formula:
𝑝
𝑒𝑓𝑓
= 𝐶 . 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 𝑟𝑒𝑎𝑑𝑖𝑛𝑔
For which:
Gas type Calibration factor C Valid range (mbar]
He
1.4 3∙10
-3
to 0.3 mbar
Ar 1.57 10
-3
to 1 mbar
H
2
0.84 3∙10
-3
to 0.2 mbar
Air, O
2
, CO, N
2
1 3∙10
-3
to 0.3 mbar
These conversion factors are average values.
1E-4
1E-3
1E-2
1E-1
1E0
1E1
1E2
1E3
1E-4 1E-3 1E-2 1E-1 1E0 1E1 1E2 1E3
A
ct
u
al
g
as
p
re
ssu
re
, m
b
ar
Transmitter reading, mbar
Air (MEMS Pirani)
Argon (MEMS Pirani)
Helium (MEMS Pirani)
Hydrogen (MEMS Pirani)
Cold Cathode reading