GE CGA 351, Руководство пользователя

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December 2004
3-8 Operation
Converting mV to
Oxygen Concentration
Although the digital display can show the oxygen concentration in
ppm or pcnt and the oxygen sensor output in mV , only one parameter
can be displayed at any given time. Therefore, it may sometimes be
helpful to manually convert a reading from one form to another. Table
3-1 below provides such information for the full range of the CGA
351, at the typical operating temperature of 700°C.
The data in Table 3-1 above was calculated with the Nernst equation.
See Appendix A,
The Nernst Equation , for details on performing such
calculations.
Powering Down
When it becomes necessary to power down the CGA 351 for service,
proceed as follows:
1.
Press the
[POWER]
button just below the digital display.
2.
Place the external disconnect device into the “OFF” position.
Caution!
Never open the door on the sensor enclosure until the
sensor has cooled to ambient temperature (in about two
hours). Rapid cooling of a hot sensor will cause cracks in
the ceramic sensor.
Any required service procedures may now be performed.
Table 3-1: Oxygen Reading Conversions
Sensor (mV) Oxygen (pcnt) Oxygen (ppm)
–32.8 100 1,000,000
15.4 10 100,000
63.7 1 10,000
111.9 0.1 1,000
160.2 0.01 100
208.4 0.001 10
256.7 0.0001 1
304.9 0.00001 0.1
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