Zero Calibration - M&C PMA Series Instruction Manual

18.1

ZERO CALIBRATION

To do a zero-point calibration of the analyzer, use an O2-free gas, e.g. nitrogen (N
below:
 Connect the flexible PVC or Viton tube with the bottle's pressure reducer of the N
Warning

First of all, open the bottle valve, then open the outlet valve of the pressure regulator;
 The pressure regulator and the tubing have to be purged for about 5 seconds;
 Check adjusted control pressure and reduce to ≤ 1.1 bar abs. if necessary, then shut-off the outlet valve of
the pressure regulator again;
 Connect the free tube end of the zero gas bottle connection to the external flow meter or, if available, to
the external calibration valve;
 Open the outlet valve of the pressure regulator slowly, in order to avoid pressure peaks;
 Adjust the zero gas volume flow with the needle valve of the flow meter to max. 60 l/h. The volume flow
of the calibration gas should always be adapted to the sample gas volume flow;
Always calibrate at the same gas flow as used for the measurement.
Note
 Wait approx. 30 seconds until display is stable;
 Set the range switch
 If necessary, adjust the zero point to 0 % via the zero point potentiometer
 Check the analogue output signals at 0% O
Ouput signal
0-10 V DC
0-20 mA
4-20 mA
If a gas mixture is analyzed, the individual components shall be checked for possible
cross-sensitivity and taken into account accordingly during zero calibration (see chapter
20).
Note

Shut the output valve of the pressure regulator and bottle valve and disconnect the tube connection to the
analyzer.
24
The pressure reducer should have a maximum outlet measuring range of 0 to
1.5 bar abs. and should always be adjusted to a low outlet pressure of max.
1.1 bar abs. This protects the measuring cell against destruction due to high
pressure!
8 (see Figure 1) to 0-1 % O
;
2
Signal to be measured
0 V
0 mA
4 mA
PMA 50 EX | 1.01.04
(with a screw driver);
2
) 5.0. Follow the steps
2
-zero gas bottle;
2
7 (Figure 1) (with a screw driver);
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