Teledyne API Model 200A NOX Analyzer Instruction Manual, 02246, Rev. G, DCN 5247
5.3.4.5 Concentration Units
The M200A can display concentrations in ppb, ppm, ug/m3, mg/m3 units. Concentrations
displayed in mg/m3 and ug/m3 use 0 C, 760 mmHg for STP. Consult your local regulations for
the STP used by your agency. The following equations give approximate conversions:
NO ppb x 1.34 = NO ug/m3
NO ppm x 1.34 = NO mg/m3
NO2 ppb x 2.05 = NO2 ug/m3
NO2 ppm x 2.05 = NO2 mg/m3
NH3 ppb x 0.76 = NH3 ug/m3 - for use with the M201A NH3 analyzer
NH3 ppm x 0.76 = NH3 mg/m3
To change the current units press SETUP-RNGE-UNIT from the SAMPLE mode and select the
desired units.
NOTE
The expected span concentration values in the new units must be
re-entered into the analyzer and the unit re-calibrated using one
of the methods in Section 7.
Changing units affects all of the RS-232 values, all of the
display values, and all of the calibration values.
Example:
If the current units are in ppb and the NO span value is
400 ppb, and the units are changed to ug/m3. A new value
must be entered for the expected span concentration.
5.3.4.6 Recorder Offset
If necessary, the analog outputs can be biased to allow operation with recorders that cannot show
slightly negative readings. The output voltage of each channel can be offset ±10% of the current
setting. It can also be used to bias the input to a datalogger to offset small external ground loop
voltages that are sometimes present in monitoring systems.
The offset is set in the V/F calibration menu. Press SETUP-MORE-DIAG, scroll to A/D
CALIBRATION, then press ENTR. Select CFG-SET-OFFSET, then enter the desired offset and
press ENTR. Press EXIT to return to the SAMPLE mode.
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