Mechanical Zero Point Adjustment - M&C PMA Series Instruction Manual

In case there are minimally different positions of the dumpbells inside the measuring cells when mounting a
new cell, it is absolutely necessary to adjust the zero point mechanically. The PMA30 housing can remain open
for this purpose;

Fix earthing cable (geen-yellow) of the transmitter unit;

Put on 18-pole flat ribbon cable to the transmitter;

Put on the 2-, 3- and 4-pole green plug connections on the main board;

Put black isolation cover over the transmitter unit.
20.2

MECHANICAL ZERO POINT ADJUSTMENT

The mechanical zero point adjustment has to be done as described in the following.
 Before switching on the analyzer, set range selector to 30 %. Control zero point of the analogue display and adjust
it if necessary to 0 % via the adjustment screw below the digital display (Attention! dependent of position: observe
position of use);
 Switch on the analyzer via external switch. Normally, the analogue display will indicate a value of 21 % oxygen
because the cell is filled with ambient air;
 The warming up is indicated by the permanently beaming LED in the front plate of the analyzer; after approx. 30
minutes, the flashing display signalizes that the required operating temperature has been reached;
 Set the potentiometer for zero point and span value in the mid position; you can do this by turning the
potentiometer with a screw driver fully to the left and then turn it five turns back to the right;
 Charge the analyzer with a zero gas volume flow of approx. 40 l/h;
 With a precise adjustment of the zero point, the analogue display should indicate 0.0 vol% oxygen;
If this does not happen, please execute the following steps:
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