Option Process Pressure Compensation Type Pd (Without Sil Certification); Option Zero Suppression With Process Pressure Compensation Type Sd/Pd (Without Sil-Certification); The Measuring Principle - M&C PMA Series Instruction Manual

9.2

OPTION PROCESS PRESSURE COMPENSATION TYPE PD (WITHOUT SIL CERTIFICATION)

In case of barometric or process originated pressure variations, the PMA 30 can be equipped with a special
pressure compensation. The compensation can be effected within a pressure range of 0.6 – 1.6 bar abs..
Thereby errors in measurement caused by pressure variations can be eliminated.
The pressure compensation can alternatively be switched on or off separately for indications and signal outlet
:

Digital indication via jumper JP1 on the front board (see figure 13 and 14)

0-10 V signal outlet via jumper JP1 on the main board (see figure 12 and page 39)

Analog indication and 20mA current signal via jumper JP2 on the main board (see figure 12 and page
39)
9.3 OPTION ZERO SUPPRESSION WITH PROCESS PRESSURE COMPENSATION TYPE SD/PD
(WITHOUT SIL-CERTIFICATION)
A zero-suppression acting on the measuring range dependent elements analog indication and 20mA current
signal is possible in 1% steps for devices with pressure compensation within a range of 1 % to 97 % O
factory provided adjusted suppression can be assigned to one or more measuring ranges via jumper JP1 on
the extension board (see figure 15 + 16).
A suppression of 97 % via jumper JP1 pos. 3 combined with the 3 % measuring range results in the new
measuring range: 97 %-100 %.
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THE 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 meas-
urement 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 dumb-
bell's movement.
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PMA30 | 1.01.03
GAS INLET
GAS OUTLET
. The
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