Teledyne API Model 200A NOX Analyzer Instruction Manual, 02246, Rev. G, DCN 5247
The calibration and zero/span checking of the M200A analyzer is treated in detail in Section 7,
Table 7-7-1 summarizes types of calibration. The basic function of each of these keys is
described here.
5.2.2.1 CAL, CALS, CALZ
The above keys control the calibration functions of the analyzer. In the CAL mode the analyzer
can be calibrated with zero/span gas coming in through the sample input port on the rear panel. If
the analyzer is equipped with the IZS option, or Zero/Span valves, there will be CALZ and
CALS buttons also. These buttons operate the Zero/Span valves or IZS system. The setup of
these options is covered in Section 6.3, and their operation is explained in Section 7.
5.2.2.2 Zero
Pressing the ZERO key along with ENTR will cause the instrument to adjust the OFFSET value
of the internal formula so that the instrument reads zero. The M200A allows zero adjustment
over a limited range of signal levels, therefore the signal does not have to be exactly zero for the
instrument to be zeroed. The instrument will not, however, allow a zero cal on any signal level,
therefore it is not possible to zero the instrument with span gas in the reaction cell. If the ZERO
key does not come on as expected, check Section 9.2.9.
5.2.2.3 Span
Pressing the SPAN key along with ENTR will cause the instrument to adjust the SLOPE value of
the internal formula so the instrument displays the span value. The expected NOx and NO span
concentrations must be entered before doing a SPAN calibration. See Table 7-7-4.
Like the Zero calibration, the Span cal cannot be done with any concentration of span gas. If the
signal level is outside certain limits the, SPAN key will not be illuminated. If you encounter this
condition see Section 9.2.9. It is also possible at low levels of span concentration that BOTH the
ZERO and SPAN keys might be on, thus allowing you to either zero or span the instrument. In
this case, care must be taken to perform the correct operation or the analyzer can become mis-
calibrated.
5.2.2.4 NO, NOx Cal Concentration
Before the M200A can be spanned, it is necessary to enter the expected span concentrations for
NO and NOx. This is done by using CAL-CONC-NOX or CAL-CONC-NO keys for NOx and
NO span concentrations, respectively. Concentration values from 30 to 19000 ppb are accepted.
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