36 of 66 Calibrations - 3654 Portable H2/N2 Analyzer
Operator Manual
ORBISPHERE
The TC sensor can be calibrated in pure H2 or N2 gas at atmospheric or elevated
pressure. The following table gives information regarding the different methods.
Before calibrating check that the sensor membrane surface is tight, smooth and wrinkle
free. Select the gas measurement phase for calibration (for full details see “Gas
Measurement Phase” on page 29). Next, select the calibration medium using the
WIN3654 program (see “Calibration Medium” on page32).
Ensure that normal measurement mode is selected in the Measurement Mode menu of
the WIN3654 program (see “Measurement Mode” on page33).
Calibration must only be carried out once the TC sensor is giving a stable measurement.
Expose the membrane to the calibration sample until this stable reading is obtained. This
usually takes about 5 minutes.
For calibration it is important that the sensor's membrane is at the same temperature as
the calibration sample. Therefore, allow some sample to pass through the flow chamber
for 3 minutes before calibrating.
Table 4-1: Sensor Calibration Information
Calibration Method Time Benefits Drawbacks Reference
Gas at atmospheric
pressure 5 min Quick and easy Less accurate than
other methods
Gas with known
purity, certified
barometer
Gas at elevated
pressure (2-3 bar) 10 min
Higher accuracy than
atmospheric method.
Validation of the
sensor linearity
Requires a certified
pressure gauge
Certified pressure
gauge