Teledyne API Model 200AH NOX Analyzer Instruction Manual, 06492, Rev. G2
7-6

7.2. Manual O2 Zero/Span Check or Cal With Zero/Span

Gas in the Sample Port
The calibration of the O2 Sensor can be checked or adjusted using gas coming in the sample port.
This method is often used when the calibration gas is supplied from the stack sample probe or
external tank and valve system.
Table 7-5 details the zero calibration procedure with zero gas coming in through the sample port.
Table 7-5: Manual O2 Zero Calibration Procedure - Zero Gas Thru Sample Port
Step Number Action Comment
1. Check “Before
Calibration” Check “Before Calibration” Section 7 above before
proceeding.
2. Press
CAL-O2-ENTR The M200AH enters the calibrate mode for O2. The zero gas
must come in through the sample port.
4. Wait 10 min Wait for reading to stabilize at zero value.
5. Press ZERO If you change your mind after pressing ZERO, you can still
press EXIT here without zeroing the instrument.
6. Press ENTR Pressing ENTR actually changes the calculation equations.
7. Press EXIT M200AH returns to sampling. Immediately after calibration,
data is not added to the DAS averages.
Table 7-6 details the span calibration procedure with span gas coming in through the sample
port.