Calibration For Oxygen; Figure 8 : Calibration For Oxygen - DALEMANS DAT 420 Calibration Manual

6.3

CALIBRATION FOR OXYGEN

1. During adjustment, avoid touching the transmitter circuit or its components with your fingers.
2. Allow the detector to be powered for at least 24 hours beforehand.
3. Position the calibration mask and connect the voltmeter as shown above.
4. Connect the cylinder of nitrogen and the flowmeter to the calibration mask, as shown above.
5. Adjust the flow rate to between 0.4 and 0.6 l/min and apply nitrogen until the voltmeter display has
stabilised (min. 2 to 3 minutes).
6. On the transmitter, adjust the "ZERO" potentiometer (figure below) to obtain 40 mV ± 0.1 mV on the
voltmeter.
VOLTMETER
mV ═
.
.
-
+
7. Stop applying nitrogen, remove the calibration mask and leave the sensor in free air for 5 to 10
minutes so that the 40..200 mV output signal stabilises completely.
8. Adjust the "GAIN" potentiometer (figure below) to obtain a reading on the voltmeter that corresponds
to the concentration of oxygen in the atmosphere (20.9 %).
The value of the reading depends upon the measuring range :
Range
0 - 25 %
9. On the control unit/PLC to which the detector is connected, check that the reading corresponds
accurately to the concentration of oxygen in the atmosphere (20.9 %).
10. Check that the sensor and transmitter are correctly positioned on their supports. Screw on the body of
the sensor housing and tighten the locking screw (Figure 5 - Page 6).
DAT420_MAN02_EN.docx • V1R1
ZERO
GAIN
+
-
"GAIN"
POTENTIOMETER
Concentration 20.9 %
I V
Measure Measure
mA mV
17.376 173.76
"ZERO"
POTENTIOMETER
I
Measure
With :
V
Measure
DAT 420
CYLINDER +
REGULATOR

Figure 8 : Calibration for oxygen

 
−
20 4
=  × 
CAL
 
Gas
Range

 
−
20 4
    
= × +
CAL

 Gas 
Range
www.dalemans.com
+
4


×
4 10

10