M&C TechGroup PMA 100-L Operator's manual - Manual (Page 6)

M&C Products Analysentechnik GmbH 9-3.12.1-ME
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the corresponding output of the amplifier, which is a current
and also proportional to the oxygen content, produces a
magnetic field in the feedback coil opposing the forces and
thereby causing the dumb bell to rotate.
Since the feedback current from the amplifier is proportio-
nal to the oxygen content of the gas sample, the output
signals produced by the amplifier will be accurate and
linear. The paramagnetic susceptibility of oxygen varies
inversely as the square of the absolute temperature. There-
fore, a temperature sensitive element in contact with the
measuring cell assembly is included in the feedback
current circuit in order to provide compensation for
changes in analyser temperature.
7.2 Flow diagram
The flow can be adjusted in a range of 25 - 60Nl/h air at the
flowmeter with needle valve 2 built on the front panel of
the analyser.
The flow sensor at the outlet of the measuring cell 3 de–
tects the sample flow if it decreases under 25l/hr.
We recommend a conditioning system upstream the
analyser PMA100-L, f.e. consisting of a cooler and fine
filter.
We like to inform you about suitable M&C equipment.
1: Measuring cell
2: „LED“ light beam
3: Photo cell
4: Feed back amplifier
5: Output amplifier
6: Meter indication
Fig. 3: Principle of operation
PMA100-L
1: external filter
2: flowmeter with needle valve
3: patented M&C measuring cell PMA100-L
4: flow control
Fig. 4: Flow diagram of the analyser
1 2 3 4
➞ ➞
1
2 3 5 4
6
PMA100-LF
1: external filter
2: flowmeter with needle valve
3: patented M&C measuring cell PMA100-L
4: flow control
1 3 4 2