12
Gas sampling and gas conditioning technology
9-3.20-MD
12.1
ZERO POINT CALIBRATION
Zero point calibration of the transmitter takes place with an O
2
-free gas, such as nitrogen (N2) 5.0.
Set the zero gas flow rate with a needle valve or flow metre to a maximum of 60 l/h. The
flow rate of the calibration gas should always be adapted to the measurement-gas flow
rate;
Wait for approx. 30 seconds until the display has stabilised.
If necessary, adjust the zero point with the zero point potentiometer to 0% = 4mA. The zero
point potentiometer must then be located approximately in the central position. If the
position of the zero point potentiometer deviates grossly from the centre position, the
mechanical zero point must be corrected (see 12.1.1). Should this no longer be possible,
the measuring cell is expected to be replaced.
Illustration 4 Calibration
