Thermo Scientific 43i Instruction Manual page 132

Calibration
Zero/Span Check
4-12 Model 43i Trace Level-Enhanced Instruction Manual
6. To ensure that the span gas is being measured at atmospheric pressure
check that the flow is approximately 0.5 LPM or more, with the excess
flowing out the atmospheric bypass.
7. Press to monitor the span gas reading and wait for the reading to
stabilize.
8. Record the difference between the measured SO
SO span concentration used. This is the span drift since the last
2
adjustment. If the calibration has changed by more than ±10%, a new
calibration should be performed.
value and the actual
2
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