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PMA45K1 | 1.00.01
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The standard
PMA 45K1
is equipped with a collective alarm output. This is a potential-free changeo-
ver contact in “safety-first position”. The capacity is 110 mA at 24 V. The following status indications
are signalized:
Light source defective,
Measuring cell uncoupled,
Flow alarm <10 / >70 Nl/h ,
Error control of power supply unit,
Power supply failure,
Temperature Transmitter <+45 °C / >+60 °C,
Fault measuring range selection.
Power supply, mV- or mA-output, remote measuring range selector as well as alarm output are effect-
ed via the cable inlets
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on the lower side of the analyzer housing.
Sample gas inlet
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and outlet
9
with ¼“ NPT i thread are also placed on the bottom side of the hous-
ing.
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MEASURING PRINCIPLE
Oxygen is a gas with a significant paramagnetic susceptibility. The molecules of oxygen are attracted
much more strongly by a magnetic field than the molecules of other gases.
The measuring principle shown in the following is benefitting from these characteristics of the oxygen.
The great advantage of the paramagnetic measuring principle is the highly reduced cross sensitivity of
the measurement to other components in the sample gas.
Figure 3 shows the diagram of the measuring cell as well as the optical system for the detection of the
dumbbell’s movement.
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4
3
1
GAS INLET
GAS OUTLET
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8
5
6
9
Figure 3
Diagram of the measuring cell and optical signal processing
