Measurement Gas Press. (Oximeter), Measurement Gas Temperature (Hygrometer); Cell Voltage; Thermocouple Voltage; Cold Junction Resistance (Cj Resistance) - YOKOGAWA ZR22G User Manual

10.1.6 Measurement gas press. (oximeter), Measurement gas
temperature (hygrometer)
Displays the preset value or the value entered by the transmitter. Turn Display the measured gas
pressure for the oximeter and the measured gas temperature for the hygrometer.
10.1.7

Cell voltage

The cell (sensor) voltage will be an index to determine the amount of degradation of the
sensor. The cell voltage corresponds to the oxygen concentration currently being measured.
If the indicated voltage approximates the ideal value (corresponding to the measured oxygen
concentration), the sensor will be assumed to be normal.
The ideal value of the cell voltage (E), when the oxygen concentration measurement temperature
is controlled at 750°C, may be expressed mathematically by:
E = -50.74 log (Px/Pa) [mV]
where, Px: Oxygen concentration in the sample gas
Pa: Oxygen concentration in the reference gas, (21 vol%O
Table 10.1 shows oxygen concentration versus cell voltage.
Table 10.1
%O 0.1
2
mv 117.83
%O 1
2
mv 67.09
%O 10
2
mv 16.35
%O 100
2
mv -34.4
10.1.8

Thermocouple voltage

The cell temperature is measured with a Type K (chromel-alumel) thermocouple. The
thermocouple cold junction is located in the detector terminal box. The cell temperature and the
thermocouple voltage (including the voltage corresponding to the cold junction temperature) are
displayed.
10.1.9

Cold Junction Resistance (CJ resistance)

The ZR22 Detector measures the cold junction temperature using an RTD (Pt 1000).
If detector is "ZR22" is selected in the "Setting", the RTD resistance values will be displayed.
10.1.10

Cell resistance

A new cell (sensor) indicates its internal resistance of 200 Ω maximum. As the cell degrades, so
will the cell's internal resistance increase.Those changes in the cell's internal resistance are just
a guide to the extent the cell is degrading. The updated values obtained during the calibration are
displayed.
10.1.11

IF software revision

The revision (number) of the interface software installed is displayed.
Oxygen Concentration Vs. Cell Voltage, (cell temperature: 750 ºC)
0.2 0.3 0.4
102.56 93.62 87.28
2 3 4
51.82 42.88 36.54
21.0 30 40
0 -7.86 -14.2
<10. Other Functions>
2
0.5 0.6 0.7
82.36 78.35 74.95
5 6 7
31.62 27.61 24.21
50 60 70
-19.2 -23.1 -26.5
IM 11M12G01-02EN
)
0.8 0.9
72.01 69.41
8 9
21.27 18.67
80 90
-29.5 -32.1
T10.1E.ai
1sh Edition : Mar. 25, 2021-00
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