Ametek CEM/Humox, Руководство пользователя

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Controller/User Interface
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4-13
Based upon the age of your cell and its characteristics, the control temperatures
should be slightly different. However if you incorrectly perform a primary calibra -
tion or if the cell really starts to deteriorate, the actual cell response to calibration
gas will drop off. The primary calibration is a why to extend the life of the cell since
the furnace control temperature can be increased as the cell ages to reduce the atro-
phy and extend the cell life if the output starts to drop off at its original factory cal
furnace set point temperature. You can tell this with the distribution that you have
in your spreadsheet since the calculated cell temperatures for some of the analyzers
are well below 695°C or above by a fair amount. If the cell response goes out of
the following limits, you will receive a zero or span gas range error. At this point,
you should perform a primary calibration and then attempt a standard calibration
again. If you get an excess cal error during primary calibration, then the furnace
temperature set point cannot be increased any further to prevent damage to the cell
housing and/or furnace assembly.
Failure limits for standard calibration -
+/- 10 mVs of the anticipated mVs for the gas concentration applied (air 0
mV expected).
+/- 5 mVs of the anticipated mVs for the gas concentration applied (2% O2
applied, 48 mV expected at 695°C cell temp) as referenced to the actual
span gas mV reading.
T/C ratio adjustment limits for Primary Calibration -
Cell Temp °C Max T/C Ratio Min T/C Ratio
615 1.3 0.7
650 1.24 0.74
695 1.22 0.777
824 1.139 0.861
790 same as 824°C
For a cell operating temperature of 695°C, the T/C ratio low limit is .777 and the
high limit is 1.222, which corresponds to a thermocouple indicated temperature
range of 540°C to 848°C.