Single Gas Sensor Module (SGSM)
Operations Manual
Super Systems Inc.
Page 26 of 38
Page 26 of 51
Figure 12- Output Calibration Page
Sensor Calibration
Calibration procedures for the in-situ H
2
analyzer (A20829) and flow-through analyzer (A20830)
have differences and similarities due to the design of each unit. Because the H
2
sensors use
thermal conductivity to quantify the %H
2
in the gas sample, how the gas is presented to the
sensor affects its calibration and resulting accuracy. The in-situ H
2
analyzer does not allow
sample gases to flow past the H
2
sensor. Therefore, the calibration must be performed in a
similar way. The flow-through H
2
analyzer requires that flows past the H
2
sensor be similar to
flows during normal operation to maximize accuracy of the sensor. The setup and calibration
methods are detailed below.
Additionally, the gas sensor must be calibrated at both the low end and high end of the
measured gas composition range to ensure accurate readings. Never perform a span
calibration without first performing a zero calibration. Performing only a zero or span
calibration will cause the sensor to give an erroneous reading. SSi suggests that this device
should be calibrated on a routine basis, such as once a year or as prescribed by the user’s
quality system requirements.
A20829
Connect the gas as illustrated below. It is recommended to let everything (gas and SGA) sit for
approximately thirty minutes to allow the temperature to achieve equilibrium.
To perform a sensor calibration, first make sure that the system is set up to flow both zero gas
(with 0% H
2
in this case) and span gas when needed. The span gas should contain a minimum
%H
2
that the sensor could be exposed to during normal operations. For example, if the sensor