Teledyne API Model 200A NOX Analyzer Instruction Manual, 02246, Rev. G, DCN 5247
7.1 Manual Zero/Span Check or Cal With Zero/Span Gas in the Sample Port
The calibration of the instrument can be checked or adjusted using gas from the sample port.
This method is often used when the calibration gas is supplied from an external calibrator and
valve system or when the Analyzer does not include the IZS or Z/S valves option.
Since the zero gas concentration is defined as 0 ppb, it is not necessary to enter the expected zero
value. Table 7-7-3 details the zero calibrate procedure with zero gas coming in through the
sample port.
Table 7-7-3: Manual Zero Calibration Procedure - Zero Gas Thru Sample Port
Step Number Action Comment
1. Press CAL The M200A enters the calibrate mode from sample mode. The
zero gas must come in through the sample port.
2. Wait 10 min Wait for reading to stabilize at zero value.
3. Press ZERO If you change your mind after pressing ZERO, you can still
press EXIT here without zeroing the instrument.
4. Press ENTR Pressing ENTR actually changes the calculation equations.
5. Press EXIT M200A returns to sampling. Immediately after calibration,
data is not added to the DAS averages.
Next, enter the expected NOx and NO span gas concentrations:
7-4
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