Teledyne API Model 200AH NOX Analyzer Instruction Manual, 06492, Rev. G2
5-20
5.3.4. Range Menu
For NOX measurements, the instrument operates on any full scale range from 5 to 5,000 ppm.
The range is the concentration value that equals the maximum voltage or current output on the
rear panel of the instrument.
If the range you select is between 5 and 500 ppm the front panel will read the concentration
anywhere from 0 to 500 ppm regardless of the range selected. If the range selected is from 501 to
5,000 ppm the front panel will read from 0 to 5,000 ppm. The apparently wider range of front
panel readouts is because the M200AH has 2 internal hardware ranges, namely 0-500 ppm and
0-5,000 ppm. The analog output is scaled for the range selected, however the front panel reading
can display correct concentrations over the entire physical range.
For O2 measurements (option), the instrument operates on any full scale range from 5 to 100
percent. The range is the concentration value that equals the maximum voltage or current output
on the rear panel of the instrument.
NOTE
Only one of the following range choices can be active at any one time.
There are 3 range choices for NOX measurements (O2 Measurements are always made on a
single range):
1. Single Range
2. Auto Range
A. Remote Range
3. Independent Ranges
5.3.4.1. Single Range (NOx Measurements)
This range option selects a single range for all output channels (NO, NOX, NO2) of the M200AH.
To select Single Range press SETUP-RNGE-MODE-SING, then press ENTR. To set the value
for the range press SETUP-RNGE-SET, and enter the full scale range desired from 5 ppm to
5,000 ppm.
5.3.4.2. Auto Range and Remote Range (NOX Measurements)
Auto Range allows each of the 3 output signals (NO, NOX, NO2) to automatically range between
a low value and a higher value. The Hi range mode is signaled by a bit on the STATUS
connector see Table 5-8. When the instrument output increases to 98% of the low range value it
will Auto Range into Hi range. In Hi range, when the output decreases to 75% of low range it
will change to the lower range. If you select a Hi range that is less than Low range, the M200AH
will remain locked in Low range and behave as a Single Range instrument.