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Teledyne API Model 200AU NO
X
Analyzer Instruction Manual, 02293, Rev. F
7-32
7.6.12.1 NO Working Standard Traced to NIST NO Standard
First, use the NIST-traceable NO standard and the GPT calibration procedure to calibrate the
NO, NO
x
, and NO
2
responses of the analyzer. Also determine the efficiency of the Molycon.
Refer to the calibration procedure described in Section 7.6.4.2.
Then, generate several NO concentrations by diluting the NO working standard. Use the nominal
NO cylinder concentration, [NO]
NOM
, to calculate the diluted concentrations. Plot the analyzer
NO response (in ppm) versus the nominal diluted NO concentration and determine the slope,
S
NOM
. Calculate the NO concentration of the working standard [NO]
STD
from:
[NO]
STD
= [NO]
NOM
x S
NOM
A procedure is presented in the TAD in Reference 2.
7.6.12.2 Other Methods of Establishing Traceability
They are:
1. NO working standard traced to NIST NO
2
standard
2. NO
2
working standard traced to NIST NO
2
standard
3. NO
2
working standard traced to NIST NO
2
standard
NOTE
For further information on calibration by GPT and NO
2
permeation
devices, refer to part 50 of Chapter 1, Title 40 CFR, Appendix F
(revised December 1, 1976) and Reference 13 of that Appendix.
7.7 Calibration of Independent Ranges or Autoranging
There are additional considerations when AutoRange or Independent Ranges are selected. The
M200AU uses one physical range of 0-2000 ppb to cover all EPA concentration ranges. The
dynamic range of the internal hardware and computer software is sufficient to cover this entire
range. Internally the range only scales parts of the 0-2000 ppb physical range to cover the
voltage range selected for the analog outputs.
7.7.1 Zero Calibration with AutoRange or Independent Range
Having one physical range to cover all EPA concentration ranges simplifies zero calibration. No
matter what AutoRange or Independent Range values are selected the values computed from a
zero calibration are the same. Therefore no special precautions need to be taken when doing a
zero calibration.