Super Systems PH2 - Manual (Page 14)

13
SSi Portable Hydrogen Analyzer
Rev A
Sensor Calibration
A proper calibration of the sensor requires two gases. The first gas should be pure Nitrogen or
Argon. This contains no Hydrogen, and is therefore referred to as the Zero Gas. The second
gas is the Span Gas. The Span Gas should ideally contain a quantity of Hydrogen similar to the
amount of Hydrogen in the process to be measured. The Span Gas should also include any
other gases that are present in the process gas in their respective percentages. The more
similar to the process gas the calibration gas is, the more accurate the calibration will be.
Performing a Zero Calibration
On the Sensor Calibration page, select Zero Hydrogen. Begin the flow of gas through the
analyzer using the flexible sample tubing assembly. The flow rate should be 1.5 to 2.0 SCFH as
measured on the flow meter in the lid of the case. The gas should not be under any pressure
other than the amount required to maintain the appropriate flow amount. The target Value is
shown on the screen. For a Zero Calibration, this will be 0.00 (the amount of Hydrogen in the
Zero Gas). The Measured H
2
Value can be seen at the bottom of the screen. When this value
comes to equilibrium, it will not be showing any upward or downward trends, only the slight
oscillation of the readings. This usually occurs in approximately 30 seconds. When the sensor
is at equilibrium, press the green Calibrate button to perform the zero calibration. After the
Zero Calibration is complete, turn off the flow of gas and disconnect it from the enclosure.
Performing a Span Calibration
To perform a span calibration, select Span Hydrogen, and flow the span gas in the same
manner as the zero gas. The Target Value should be set to the exact amount of Hydrogen that is
in the Span Gas cylinder. Then the same procedure should be followed as the Zero calibration,
with the Calibrate button being pressed after the readings reach equilibrium. After the Span
Gas calibration is complete, turn off the flow of gas, disconnect the cylinder from the enclosure.