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DAT420_MAN02_EN.docx • V1R1
10
DAT 420
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.
Figure 8 : Calibration for oxygen
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
Concentration 20.9 %
With :
4
4
20
+
−
×
=
Range
Gas
CAL
Measure
I
I
Measure
mA
V
Measure
mV
0 - 25 %
17.376
173.76
10
4
4
20
×
+
−
×
=
Range
Gas
CAL
Measure
V
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).
CY
REGULATOR
VOLTMETER
mV
═
+
-
+
-
.
.
ZERO
GAIN
"GAIN"
POTENTIOMETER
"ZERO"
POTENTIOMETER
