Yokogawa Single Channel Oxygen Analyzer System ZR22/ZR402 - Manual (Page 150)

IM 11M12A01-03E 10-2
10.1.1.2 Response Time
The cell’s response time is obtained in the procedure shown in Figure 10.3. If only
either a zero-point or span calibration has been carried out, the response time will not be
measured just as it will not be measured in manual calibration.
mA
90%
100%
The response time is obtained after the corrected calibration curve has been found. The response time
is calculated, starting at the point corresponding to 10% of the analog output up to the point at 90% of
the analog output span. That is, this response time is a 10 to 90% response.
10% of analog
output span
Five minutes maximum
Response time
Start calibration
Time
Calibration
complete
F10.3E.EPS
Figure 10.3 Functional Drawing of Response Time
10.1.1.3 Robustness of a Cell
The robustness of a cell is an index for predicting the remaining life of a sensor and is
expressed as one of four time periods during which the cell may still be used:
(1) more than a year
(2) more than six months
(3) more than three months
(4) less than one month
The above four time periods are tentative and only used for preventive maintenance, not
for warranty of the performance.
This cell’s robustness can be found by a total evaluation of data involving the response
time, the cell’s internal resistance, and calibration factor. However, if a zero or span
calibration was not made, the response time cannot be measured. In such a case, the
cell’s robustness is found except for the response time.
10.1.1.4 Cell Temperature
This indicates the cell (sensor) temperature, usually indicating 750
ЊC., obtainable from
the thermoelectromotive force and cold junction temperature described below.
10.1.1.5 Cold Junction Temperature
This indicates the detector terminal box temperature, which compensates for the cold
junction temperature for a thermocouple measuring the cell temperature. When the ZR22
Detector is used, the maximum Cold Junction temperature will be 150
ЊC. If the terminal
box temperature exceeds this, take measures, for example, so that the terminal box is not
exposed to radiation to reduce that temperature.
The maximum Cold Junction temperature varies depending on the type of detector.