Vaisala AQT400, User Manual

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6. To change the calibration values, use the command line interface.
Use the following parameters to adjust internal gas measurements:
• co_span
• no2_span
• o3_span
• so2_span
• co_zero
• no2_zero
• o3_zero
• so2_zero
The span adjustment is proportional and is represented as a percentage value, which
can vary between
1 ... 255 (default = 100 ). The zero adjustment is an absolute value in
ppb and it is added after span adjustment. The zero values can vary between
-10000 ... 10000 . Use the show command to read the concurrent values before using
the set command to replace them. If AQT400 has an offset adjustment (zero value
other than 0 ), take the old value in count before setting a new one. This also applies to
span values.
7. Use the write --really command to save the new adjustments.
8. Use the show health command to check the health status of AQT400. The output is a
percentage value (0 ... 100 %). If the health value is below 20 , contact Vaisala technical
support.
Appendix A – Performance Check
41