Zero And Span Check - Thermo Scientific 43iQ Instruction Manual

Zero and Span
Check
43iQ Instruction Manual
12. From the Home Screen, choose Calibration>Calibrate Low Range
Span Coefficient.
The user sets the span concentration by pressing the Edit Low range
Span Concentration button. The Calculated Low Range Span
Coefficient button will show what the low span coefficient will be set to
if the Calibrate button is pressed. Pressing the Calibrate button will
save the new low range coefficient and calibrate the instrument.
13. Enter the SO calibration gas concentration using the pushbuttons, and
2
then press Calibrate to calibrate the instrument to the low range SO
calibration gas.
The zero and span check procedure is normally performed any time a quick
check of the accuracy of the instrument is required. Normally, zero and
span are checked daily. As experience is gained with the instrument, the
frequency of these checks can be adjusted accordingly.
The span gas concentration used in the span check should be between 70%
and 90% of the full-scale range. The zero and span drift should be
measured and recorded prior to making any adjustments.
All gas must be supplied to the instrument at atmospheric pressure. It will
be necessary to employ an atmospheric bypass plumbing arrangement to
accomplish this.
If a filter is used, all gas must enter the instrument through the filter.
Use the following procedure to check the zero/span.
1. If the instrument is equipped with the optional zero/span and sample
valves, connect the zero and span gas to the rear panel bulkheads
labeled ZERO IN and SPAN, otherwise connect a source of vented
zero air to the SAMPLE bulkhead.
Note Do not use nitrogen for zero air.
2. To ensure that the zero air is being measured at atmospheric pressure,
check that the zero air flow reported by the analyzer is approximately
0.5 LPM. Actual zero air flow should be 0.8 LPM or more, with the
excess flowing out the atmospheric bypass.
a. From the Home screen choose Settings>Health Check>Status
and Alarms>Flow and Pressure.
L
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